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Clouds play a pivotal role in determining Earth's climate, impacting several atmospheric processes influencing the weather. The study explores the temporal variations in cloud base height (CBH) over Pune, a tropical station, from 2017 to 2023 using a Laser-Based Ceilometer with a range of 0–7500 m. Our analysis shows seasonal trends in CBH, with the monsoon season exhibiting unique characteristics showing the lowest average CBH and minimal diurnal changes during the study period. Conversely, the pre-monsoon, post-monsoon, and winter season show a gradual rise of CBH in the morning, maintaining higher levels until late afternoon, followed by a decline in the evening. Analysis of the diurnal frequency of cloud occurrence at 500 m intervals reveals the monsoon season's dominance in the 500 m to 1000 m layer. Throughout the year, low cloud bases (CBH <2000 m) are most frequent, outpacing the frequency of mid and high cloud bases. High cloud base (7500 < CBH > 6000 m) is the least common, showing a semi-diurnal pattern in winter with peaks around noon and midnight. These findings not only enhance our understanding of Pune's atmospheric behaviour but also offer valuable information for weather prediction, climate modelling, and environmental monitoring. [ABSTRACT FROM AUTHOR]

The present study aimed to elucidate the effects of real-time versus slow-motion videos, as a function of time of day, on the acquisition of basketball plays. Fifty first-year sports science students (Mage = 18.82 y, SD = 0.49) were quasi-randomly allocated to either into 0.5 or 1.0 times normal video speed, attending morning (08:00–09:00 h) and late-afternoon (16:00–17:00 h) sessions. After measuring oral temperature (OT) and mood states (MS), participants observed a basketball system's evolution twice and completed two recall tests [game comprehension (GC) and game performance (GP) tests]. Afternoon sessions exacerbated higher OT, higher negative MS (e.g. anxiety and fatigue), and lower positive MS (i.e. vigor) compared to mornings (regardless of video speed). GC and GP were higher in the morning than in the afternoon, with real-time (p < 0.001, both) and slow-motion videos (p < 0.01 and p < 0.001, respectively). GC and GP were higher with slow-motion videos compared to real-time videos in morning and afternoon sessions (p < 0.01, both). The findings highlight the morning's superiority in the acquisition of motor knowledge from videos, due to mood disturbances and lower arousal levels. Additionally, the findings encourage teachers/coaches to communicate basketball plays through slow-motion videos, particularly in the morning. [ABSTRACT FROM AUTHOR]

The purpose of this study was to examine the effects of time of day on technical and physical performance parameters in young female tennis players. A sample of 12 recreational tennis players (age 24.2 ± 3.8 years) were randomly distributed into two groups. After having their demographics (age, experience, chronotypes), they were measured for body mass, body temperature, serve accuracy, serve speed, countermovement jump, grip strength, agility, and linear speed by counterbalancing method on two different days and at two different times of the day (09:00 and 16:30). The main results revealed that the players had significantly (p < 0.01) higher body temperature and greater values in the grip strength test during the afternoon session in comparison to the morning session. On the other hand, no significant differences (p > 0.05) were observed for other physical and technical performance parameters. The findings may highlight that time of day has no significant effects on several tennis-related performance determinants in female recreational players. [ABSTRACT FROM AUTHOR]

Circadian rhythms play a pivotal role in governing various physiological processes, including physical performance. However, in individuals deprived of light perception, such as the blind, these circadian rhythms face disruption. This study aimed to explore the influence of disturbed circadian rhythms on short-term maximal physical performance in children and adolescents with visual impairment. Forty-five volunteers participated in this study, comprising 17 blind, 13 visually impaired, and 15 sighted participants. The participants underwent a series of tests assessing maximal isometric strength performance across two days. To mitigate the influence of morning session fatigue on the evening results, each participant group performed in two separate testing sessions (i.e. in the morning (7:00 h) and in the evening (17:00 h)) on non-consecutive days in a randomized and counterbalanced setting, with approximately 36 h of recovery time between sessions. To mitigate the impact of inter-individual differences on mean values and to account for the influence of age and sex on the studied variables, data were normalized. The outcomes revealed a significant diurnal variation in maximal isometric strength performance among sighted individuals, with peak performance observed in the evening. This pattern aligns with their well-entrained circadian rhythm. In contrast, blind and visually impaired individuals did not display significant diurnal variation, signaling disrupted circadian rhythms due to the absence of light perception. These findings emphasize the crucial consideration of circadian rhythms in assessments of physical performance, especially among participants with visual impairments. [ABSTRACT FROM AUTHOR]

The present cross-sectional study aims to examine the effect of time of day on the judo-specific performance in judokas, considering their chronotypes. Twenty-four male judokas participated in the study where the Morningness-Eveningness Questionnaire was administered, and on it, they were divided into morning-type (MT:12-judokas) and evening-type groups (ET:12-judokas). Afterwards, the Special Judo Fitness Test (SJFT) was applied to both groups at three different times (morning: 09:00 h, afternoon: 13:00 h and evening: 17:00 h) with body temperature measured before and after every SJFT performance. As a result, the Group*Test Time interaction significantly affected overall throwing performance during SJFT [F(2,44) = 29.437, p = 0.001, η2p:.572]. Furthermore, a significant time effect was found for the SJFT index [F(2,44) = 5.118, p = 0.010, η2p:.189] and for the Group*Test Time interaction with the mean value of the index [F(2,44) = 24.424, p < 0.001, η2p:.526]. Furthermore, body temperature had a significant time effect [F(2,44) = 301.454, p < 0.001, η2p:.932] and the Group*Test Time interaction [F(2,44) = 5.802, p = 0.006, η2p:.209]. In conclusion, coaches and exercise experts should consider judo athletes' chronotype when planning special training programs to improve judo-specific anaerobic capacity. Furthermore, to minimize the impact of time of day and chronotype on athletes' performance in competitions, it is recommended that MT athletes develop their judo-specific anaerobic capacity in the evening hours, when their performance is lower, while ET athletes should do so in the morning hours when their performance is lower via randori training. [ABSTRACT FROM AUTHOR]

Sprint and jump performances represent performance-determining parameters in individual and team sports. Fluctuations in performance depending on the daytime raise the question of the best time to train and compete. Given the scarce research on females, this study aimed to analyze the influence of daytime on sprint and jump performances and to investigate whether the performance difference is related to the chronotype. Thus, 23 female sports students completed a questionnaire to assess their chronotype followed by performing two 30 m sprints, 5 Repeated Jump Tests (5RJT), and countermovement jumps (CMJ) in the morning (7:00–9:00 h) and evening (17:00–19:00 h). Time after 5 m, 10 m, and 30 m during the sprints, reactive strength index (RSI) during the 5RJTs, and jump height during the CMJs were examined. The performance during the 30 m sprint (t(22) = 5.28, p < 0.01 moderate effect size: 0.50) and the two jump tests (5RJT: t(22) = 8.27, p < 0.01 large effect size: 0.95; CMJ: t(22) = 5.46, p < 0.01 moderate effect size: 0.79) were significantly better in the evening than in the morning. There was no significant correlation between chronotype and the time-of-day effect. The results should be considered when planning training and competition. [ABSTRACT FROM AUTHOR]

We have investigated the effects that partial-sleep-restriction (PSR0, 4-h sleep retiring at 02:30 and waking at 06:30 h for two consecutive nights) have on 07:30 and 17:00 h cognitive and submaximal weightlifting; and whether this performance improves at 17:00 h following a 13:00 h powernap (0, 30 or 60-min). Fifteen resistance-trained males participated in this study. Prior to the experimental protocol, one repetition max (1RM) bench press and back squat, normative habitual sleep and food intake were recorded. Participants were familiarised with the testing protocol, then completed three experimental conditions: (i) PSR with no nap (PSR0); (ii) PSR with a 30-min nap (PSR30) and (iii) PSR with a 60-min nap (PSR60). Conditions were separated by 7 days with trial order counterbalanced. Intra-aural temperature, Profile of Mood Scores, word-colour interference, alertness and tiredness values were measured at 07:30, 11:00, 14:00, 17:00 h on the day of exercise protocol. Following final temperature measurements at 07:30 h and 17:00 h, participants completed a 5-min active warm-up before performing three repetitions of left and right-hand grip strength, followed by three repetitions at each incremental load (40, 60 and 80% of 1RM) for bench press and back squat, with a 5-min recovery between each repetition. A linear encoder was attached perpendicular to the bar used for the exercises. Average power (AP), average velocity (AV), peak velocity (PV), displacement (D) and time-to-peak velocity (tPV) were measured (MuscleLab software) during the concentric phase of the movements. Data were analysed using general linear models with repeated measures. The main findings were that implementing a nap at 13:00 h had no effect on measures of strength (grip, bench press or back squat). There was a main effect for time of day with greatest performance at 17:00 h for measures of strength. In addition to a significant effect for "load" on the bar for bench press and back squat where AP, AV, PV, D values were greatest at 40% (P < 0.05) and decreased with increased load, whereas tPV and RPE values increased with load; despite this no interaction of "load and condition" were present. A post lunch nap of 30- and 60-minute durations improved mood state, with feelings of alertness, vigour and happiness highest at 17:00 h, in contrast to confusion, tiredness and fatigue (P < 0.05), which were greater in the morning (07:30 h). The word-colour interference test, used as an indicator of cognitive function, reported significant main effect for condition, with the highest total test score in PSR60 condition (P = 0.015). In summary, unlike strength measures the implementation of a 30 or 60-minute nap improved cognitive function when in a partially sleep restricted state, compared to no nap. [ABSTRACT FROM AUTHOR]

The measurement of tear film osmolarity has been suggested as a gold standard in the diagnosis of dry eye. Many tear film physiological variables oscillate during the day. This review summarises current clinical knowledge regarding diurnal osmolarity variation in the tear film. A critical analysis is presented in respect of of sample size and characteristics, differences in the diurnal osmolarity variation on healthy versus altered tear film conditions or environment, and time of day and number of measurements undertaken. A comparison of 21 studies was made for studies in which one of the main objectives was to analyse the variance of tear film osmolarity at different time-points in a day on human cohorts. Tear film osmolarity appeard to be somewhat influenced by the time of day in healthy subjects and patients with ocular surface disease, or altered by environmental conditions. Both healthy and non-physiological tear film cohorts showed variations in results depending on the study: no variations during the day or statistically different values at some point in the day. These differences could be in the middle of the day or between the beginning and the end of the day, with higher values in the morning than in the afternoon, or even the opposite situation. The possibility of diurnal variations in tear film osmolarity should be considered by the clinician since the time of day when the tear film measurements are made can be critical in making the right diagnosis. Future studies in the diurnal variation field may have to use a well-established range of measurement time-points and a larger group of healthy subjects and and subjects who have a tear film altered by pathological or environmental conditions. [ABSTRACT FROM AUTHOR]

There is limited information on diurnal variation in pulmonary artery pressures (PAP) in ambulatory heart failure (HF) patients. We aimed to study the variation in morning and night-time PAP in HF patients with an implanted CardioMEMS® sensor. In this prospective, single centre study we enrolled patients who had a cardioMEMS sensor and consented to participate (End stage renal disease and recent hospitalisation for acute HF were exclusions). Subjects were asked to transmit PAP and non-invasive blood pressure information in morning and at night-time for 7 consecutive days. Categorical and continuous variables were reported as percentages and mean ± SD respectively. Repeated measure ANOVA was used to compare the diurnal changes in PAP among different subgroups. Pierson correlation coefficient was performed to assess correlation between diurnal variation of PAP and left ventricular ejection fraction Thirty subjects were included in analysis. There was a significant nocturnal rise in PASP and mPAP compared to morning readings (+2.59 mmHg, p = 0.003 and +1.24 mmHg with p = 0.02 respectively) while night-time PADP did not change significantly (+0.48 mmHg, p = 0.18) without significant change in systemic blood pressure or pulse rate. The described diurnal changes in PAP should be considered when managing ambulatory HF patients based on these readings. PADP can be used reliably without concern for the time of day the readings were recorded. There is a diurnal variation in PAP in ambulatory heart failure patients Pulmonary artery systolic and mean pulmonary artery pressures are higher at night-time than in morning. Pulmonary artery diastolic pressures do not vary significantly with time of day. These findings should inform clinical decisions in management of these patients about the time of the day readings are taken [ABSTRACT FROM AUTHOR]

Fractional exhaled nitric oxide (FeNO) is considered to be an adjunct for asthma management, although its usefulness remains controversial. Therefore, it may be necessary for new approaches to use FeNO for asthma management. We evaluated whether diurnal variations of FeNO can predict response to asthma treatment. This pilot study consisted of 22 uncontrolled asthmatics and 16 healthy subjects. FeNO and peak expiratory flow (PEF) were measured by themselves twice daily at home for three weeks (asthmatics) or two weeks (healthy subjects), and daily mean and diurnal variations of FeNO and PEF levels were calculated. In uncontrolled asthmatics, treatment was intensified a week after study entry, and then control status was reevaluated after three to four weeks. Asthmatics were then divided into two groups; good or poor responders. Diurnal variations of FeNO levels, as well as daily mean FeNO and PEF levels, in uncontrolled asthmatics before intensive treatment were significantly higher than those in healthy subjects, regardless of treatment response (p < 0.01). Furthermore, in the good responders, diurnal variations of FeNO levels were significantly decreased in the 1st week (p < 0.05) of intensive treatment, whereas the daily mean FeNO levels significantly dropped in the 2nd week (p < 0.05). In the poor responders, no such changes were observed in FeNO levels. In terms of PEF, only the daily mean levels were significantly elevated after the initiation of intensive treatment, regardless of treatment response. Diurnal variations of FeNO may contribute to predicting early therapeutic response to asthma treatment. [ABSTRACT FROM AUTHOR]

The aim of this study is to examine the daytime effects on flip turn performance [i.e., 3 m round trip time (3mRTT) as measure of turning performance] as well as global performance during a 50 m freestyle at maximal speed. Twelve college swimmers performed 3 × 50 m freestyle at maximum speed with a flip turn and glide in a 25 m pool in two experimental trials, one in the morning (08:00 h) and one in the evening (18:00 h). Kinematic and dynamic parameters of flip turn performance are analyzed using one underwater camera and a force platform recording wall force peak and time contact. Results showed that oral temperature is significantly higher (p < 0.001) in the evening than in the morning. Also, this study reported that daily variations have been observed for both, changes in swim performance and changes in (3mRTT). Thus, kinematic and dynamic flip turn variables associated with an improvement of freestyle swim performance. It is concluded that maximal swimming trials are performed better in the evening than in the morning, and that this might be linked to variations in oral temperature; also, might be explained by better flip turn performance at this time. [ABSTRACT FROM AUTHOR]

Few functional measures related to time-trial display diurnal variation. The diversity of tests/protocols used to assess time-trial performance on diurnal effects and the lack of a standardised approach hinder agreement in the literature. Therefore, the aims of the present study were to investigate and systematically review the evidence relating to time-of-day differences in time-trial measures and to examine the main aspects related to research design important for studies of a chronobiological nature. The entire content of Manipal Academy of Higher Education electronic library and Qatar National Library, and electronic databases: PubMed (MEDLINE), Scopus and Web of Science were searched. Research studies published in peer-reviewed journals and non-peer reviewed studies, conducted in male adult participants aged ≥18 y before November 2021 were screened/included. Studies assessing tests related to time-trials in any modality between a minimum of 2 time-points during the day (morning [06:30–10:30 h] vs evening [14:30–20:00 h]) were deemed eligible. The Grading of Recommendations Assessment, Development, and Evaluation (GRADE) process was used to assess the evidence to inform recommendations. The primary search revealed that a total of 10 from 40 articles were considered eligible and subsequently included. Six were conducted using cycling, two using running and two using swimming as the mode of exercise. Distances ranged from 1 to 16.1-km in distance or 15 to 20-min time in the cycling and running time-trials, and 50 to 200-m in the swimming time-trials. Only four studies found one or several of their performance variables to display daily variations, with significantly better values in the evening; while six studies found no time-of-day significance in any variables assessed. The magnitude of difference ranged from 2.9% to 7.1% for performance time to complete a cycling time-trial, while running and swimming did not find any differences for performance time. Power output during a 16.1-km time trial in cycling also found evening performance to be significantly better by 10%. The only other observed differences were stroke rate and stroke length during a swimming time-trial and stroke rate (cycles.min−1) during a cycling time-trial. The magnitude of difference is dependent on exercise modality, individual chronotype, the training status of the individual and sample size differences. The lack of diurnal variation present in the majority of studies can in-part be explained with some of the methodological limitations and issues present related to quality and control. It is paramount that research assessing diurnal variation in performance uses appropriate session timings around the core body temperature minimum (~05:00 h; morning) and maximum (~17:00 h; evening). Although, differences in motivation/arousal, habitual training times, chronotypes and genotypes could provide an explanation as to why some studies/variables did not display time-of-day variation, more work is needed to provide an accurate conclusion. There is a clear demand for a rigorous, standardised approach to be adopted by future investigations which control factors that specifically relate to investigations of time-of-day, such as appropriate familiarisation, counterbalancing the order of administration of tests, providing sufficient recovery time between sessions and testing within a controlled environment. [ABSTRACT FROM AUTHOR]

The present study examined the effect of time-of-day in psychological responses and short-term maximal performances in elite male handball players. Eighteen male handball players performed, in a counterbalanced order and at three time-of-day (i.e., in the morning at 10:00 h, in the afternoon at 14:00 h and in the evening at 18:00 h) the Repeated Sprint Ability (RSA) and the Ball-Throwing Velocity (BTV) test. Profile of mood states (POMS), simple (SRT) and choice (CRT) reaction times, and Stroop test to evaluate selective attention (SA) and Hooper questionnaires were assessed before the physical tests. Oral temperature (OT) was measured in the beginning of each testing session. The results revealed, for the POMS questionnaire, that the negative mood-states (anxiety, anger, confusion, depression, and fatigue) were higher in the morning while positive mood-state (vigor) was higher in the evening. Also, SRT, CRT and SA were better in the evening. For physical tests, BTV and performance during the RSA test were also better in the evening. OT was higher in the evening than in the morning and the afternoon. The findings suggest that, in elite handball players, cognitive and short-term maximal physical performances were better increased during the day from the morning to the evening. [ABSTRACT FROM AUTHOR]

Numerous functional measures related to anaerobic performance display daily variation. The diversity of tests and protocols used to assess anaerobic performance related to diurnal effects and the lack of a standardized approach have hindered agreement in the literature. Therefore, the aim of the present study was to investigate and systematically review the evidence relating to time-of-day differences in anaerobic performance measures. The entire content of PubMed (MEDLINE), Scopus, SPORTDiscus® (via EBSCOhost) and Web of Science and multiple electronic libraries were searched. Only experimental research studies conducted in male adult participants aged ≥ 18 yrs before May 2021 were included. Studies assessing tests related to anaerobic capacity or anaerobic power between a minimum of two time-points during the day (morning vs evening) were deemed eligible. The primary search revealed that a total of 55 out of 145 articles were considered eligible and subsequently included. Thirty-nine studies assessed anaerobic power and twenty-five anaerobic capacity using different modes of exercise and test protocols. Forty-eight studies found several of their performance variables to display time-of-day effects, with higher values in the evening than the morning, while seven studies did not find any time-of-day significance in any variables which were assessed. The magnitude of difference is dependent on the modality and the exercise protocol used. Performance measures for anaerobic power found jump tests displayed 2.7 to 12.3% differences, force velocity tests ~8% differences, sprint tests 2.7 to 11.3% differences and 5-m multiple shuttle run tests 3.7 to 13.1% differences in favour of the evening. Performance measures for anaerobic capacity found Wingate test to display 1.8 to 11.7% differences and repeated sprint tests to display 3.4 to 10.2% differences. The only test not to display time-of-day differences was the running based anaerobic sprint test (RAST). Time-of-day variations in anaerobic performance has previously been partially explained by higher core-body and/or muscle temperature and better muscle contractile properties in the afternoon, although recent findings suggest that differences in methodology, motivation/arousal, habitual training times and chronotypes could provide additional explanations. There is a clear demand for a rigorous, standardised approach to be adopted by future investigations which control factors that specifically relate to investigations of time-of-day. [ABSTRACT FROM AUTHOR]

The combined effect of Ramadan fasting and the time of theday on the physical performance of team-handball players has not yet been fully investigated. This study investigated the effects of Ramadan fasting on the morning–evening difference in team-handball-related short-term maximal physical performance. With acounterbalanced study design, 15 elite female team-handball players underwent the hand grip (HG), ball throwing velocity (BTV), modified agility T-test (MAT), and repeated shuttle-sprint and jump ability (RSSJA) tests at 07:00 h and 17:00 h, one week before Ramadan (BR), and during thesecond (SWR) and fourth week of Ramadan (4WR). The oral temperature (OT) was monitored prior to exercise and the ratings of perceived exertion (RPE) scale were obtained after RSSJA. The results showed that the time of theday had an effect on OT under all conditions. The HG, BTV, and MAT test performances were higher in the evening than in the morning BR (P<.001, P<.05, and P<.001, respectively). However, the diurnal variation noted in the HG and MAT tests was reversed during the SWR and 4WR, while the BTV variation was blunted during the SWR and reversed during the 4WR. The best RSSJA performance was observed in the evening BR. However, for the best and mean sprint times, areversal of this diurnal variation was observed, which was blunted for the mean jump height and sprint time decrement during Ramadan. Moreover, RPE were influenced by the time of theday and the month of Ramadan. These findings suggest that the diurnal variation of team-handball-related short-term maximal physical performance may be reversed and/or blunted during Ramadan fasting. [ABSTRACT FROM AUTHOR]

The present study aimed to investigate the effects of caffeine ingestion and one night of total sleep deprivation on the diurnal variation of cognitive and short-term maximal performances. In a randomized order, thirteen active male completed eight test sessions at 08:00 h and 18:00 h after a placebo or caffeine ingestion (5 mg•kg-1) after a reference night (RN) or a night of total sleep deprivation (TDN). During each session participants performed the simple and the choice reaction time (SRT and CRT), the profile of mood states (POMS), the squat jump (SJ) and the 30-s Wingate tests (peak (PP) and mean (MP) powers and the fatigue index (FI)). After RN, PP, MP and SJ improved significantly from the morning to the afternoon (P<0.001). In the placebo condition compared to RN, they decreased significantly after TSD only in the afternoon (p<0.001). However, POMS, SRT and CRT increased significantly after TSD (p<0.001). The caffeine ingestion improved PP, SRT, CRT and POMS after TSD compared to RN (p<0.001) and SJ after the two sleep conditions (p<0.001). Therefore, POMS, SRT, CRT and physical performances are time-of-day dependent and caffeine is an effective strategy to counteract the effect of sleep loss on these performances. [ABSTRACT FROM AUTHOR]

Reduced flow-mediated dilation (FMD) and elevated plasma endothelin-1 (ET-1) levels may contribute to the higher incidence of adverse cardiovascular events observed in the morning hours. A single bout of intermittent exercise abolishes the diurnal variation in FMD. Studies examining the effects of exercise on vascular and plasma ET-1 responses at different times of day are lacking. We determined the effects of time of day and intermittent aerobic exercise on brachial artery FMD and plasma ET-1 levels in healthy adults. We hypothesized that lower brachial artery FMD in the morning (compared to the afternoon) will be accompanied by higher plasma ET-1 levels. Additionally, we hypothesized that the diurnal variation in brachial artery FMD and plasma ET-1 will be abolished by performing a single bout of intermittent aerobic exercise. Utilizing a randomized, cross-over design, healthy adults [n = 12; 22 ± 4 y; 25.2 ± 2.7 kg/m2] completed two separate trials: morning (08:00 h) and afternoon (16:00 h). Brachial artery FMD and plasma ET-1 were measured prior to and immediately following a bout of intermittent cycling performed at 70% peak Watts. Brachial artery FMD was lower (P <.05) at 08:00 h (4.4 ± 3.4%) compared to 16:00 h (6.3 ± 3.7%), but was unaffected by exercise (4.8 ± 3.9% and 5.7 ± 2.2% for 08:00 h and 16:00 h, respectively). Plasma ET-1 was unaffected by time of day. Compared to pre-exercise, plasma ET-1 decreased (P <.01) at both times of day. Our data indicate that circulating ET-1 levels do not explain the lower morning FMD in healthy adults. Further, a bout of intermittent exercise did not affect brachial artery FMD but decreased plasma ET-1 levels. [ABSTRACT FROM AUTHOR]

This study assessed the effect of time of day (TOD) and listening to music during warm-up on cognitive and physical performances after partial sleep deprivation (PSD) and normal sleep nights (NSN). In a randomized order, twelve male physical education students [mean (SD) age 20.3 ± 2.0 y; BMI 22.90 ± 3.57 kg/m2)] completed a 30-s Wingate test (i.e., mean (MP) and peak powers (PP)), simple (SRT) and choice reaction times (CRT), a mental rotation test (MRT) and a selective attention test. Measurements were performed at 07:00 h and 17:00 h after a NSN and PSD with and without music, with an in-between recovery period of ≥72. Salivary cortisol was measured before and immediately after the Wingate test. Compared to NSN, the results showed that PSD decreased PP (p <.05, d = 0.86) and MP (p <.01, d = 0.86) in the afternoon. However, compared to NSN, listening to music during the warm up after PSD enhanced PP (p <.01, d = 1.40) and MP (p <.05, d = 0.82) in the morning and PP (p <.05, d = 0.78) in the afternoon. Moreover, listening to music lowered post-exercise cortisol in the morning both after NSN (p <.05, d = 0.79) and PSD (p <.05, d = 0.11). After PSD, music reduced the negative mood states (p <.01, d = 0.94), the SRT (p <.05, d = 0.79) and the CRT (p <.05, d = 0.49) in the afternoon. These findings suggest that listening to music during warm-up (i) enhances cognitive and short-term all out performances after NSN and PSD and (ii) partially counteracts sleep-loss-induced degradation of physical and cognitive performances at both TODs. [ABSTRACT FROM AUTHOR]

Various biomarkers of oxidative stress and redox status have been used in a number of clinical and epidemiological studies related to diseases and conditions that involve disturbances of the redox balance. However, a comprehensive study of diurnal variations of a set of biomarkers has not been conducted so far. Therefore, the aim of this study is to investigate circadian rhythm and time-of-day-effects of a set of frequently used biomarkers of oxidative stress, redox and antioxidant status in serum/plasma. These biomarkers include Reactive Oxygen Metabolites (ROM), Biological Antioxidant Potency (BAP), Total Thiols in Proteins (TTP), high-sensitive C-Reactive Protein (CRP) and Uric Acid (UA). During a 24-hr study, blood sampling was conducted 6 times at 4-hr intervals. The presence of circadian rhythm was analyzed with CircWave analysis, whereas the effect of time was analyzed with Repeated Measures ANOVA (RM-ANOVA). Thereby, the main focus was on the time points in working hours (8, 12 and 16 hr), which are used frequently in practice. Of all investigated biomarkers, only TTP in males demonstrated statistically significant circadian rhythm (p = 0.040). A statistically significant effect between all six time points with RM-ANOVA was observed for ROM, TTP and UA in both genders, and for BAP in females only. No statistically significant differences were observed between the time points 8 hr and 12 hr for any of the biomarkers that were assessed in our study. In conclusion, diurnal variations in some of the studied biomarkers that we demonstrate here should be taken into account when designing and conducting clinical and epidemiological studies. It is advised to standardize the time of sampling with a preference in the morning hours. [ABSTRACT FROM AUTHOR]

Time of drug administration affects both the kinetics and dynamics of medications. This study investigated diurnal efficacy of alpha-lipoic acid (ALA), nifedipine, and glimepiride combination in the treatment of diabetic retinopathy. The study design comprised seven groups of rats, with groups 1 and 2 serving as non-diabetic and diabetic controls, respectively, receiving 1 ml/kg distilled water. All other groups were diabetic, and received 10 mg/kg glimepiride at 20:00 h. Groups 4–7 also received 20 mg/kg nifedipine at 08:00 h. In addition, groups 5–7 received 100 mg/kg ALA at 08:00 h, 14:00 h, and 20:00 h, respectively. Oral drug administration was for 28 days during which fasting and random blood glucose sampling were done weekly at 07:30 h and 13:30 h, respectively. On the 29th day, rats were euthanized; blood was collected via the jugular veins for determination of serum ocular markers like magnesium, cholesterol, and triglyceride. Furthermore, the eyes were excised and their relative organ/body weight ratios determined. The right eyes were persevered in phosphate buffer for homogenization and determination of retina antioxidant profile (MDA, SOD, CAT, GSH), while the left eyes were preserved in formalin for histological examination. Results showed that treatment with ALA and glimepiride at 20:00 h along with nifedipine at 08:00 h resulted in better prognosis than other treatment groups and with improved glycemic control. Also, all their serum markers for retinopathy, organ weight, and histology did not differ significantly from that of the non-diabetic rats. Findings imply that diurnal efficacy in alpha-lipoic acid, nifedipine and glimepiride combination ameliorates diabetic retinopathy in rats and may be beneficial in the treatment of diabetic retinopathy. [ABSTRACT FROM AUTHOR]

The diurnal and seasonal variation study has been performed for soil radon time series (RTS) data obtained using RTM-1688 radon monitor (SARAD GmbH, Dresden, Germany). Data were collected from radon station installed at latitude 34.39621 and longitude 73.47347 on fault line passing beneath the Muzaffarabad city, for a period of 1 year. RTS data were analysed based upon their monthly recorded values followed by an interpretation of season-wise data, based upon 10-day measurements, in order to get more insight into radon variations. Minimum value of 1.3553 × 104 Bq m−3 was recorded for the first 10 days of the month of March 2017, whilst maximum value 2.7902 × 104 Bq m−3 was recorded from 8th to 17th day of August 2017. Overall mean value for RTS data were found to be (2.1024 ± 0.2088) × 104 Bq m−3. Data obtained for the current study show that the variations observed in the season of spring are comparatively smaller in magnitude than the other three seasons. Month-based correlation between soil radon gas with environmental parameters has also been investigated for the entire study period. For the months starting from March to September, a positive correlation of radon in soil with the relative humidity and pressure has been observed while no significant correlation was found between radon in soil and temperature for these months. For October to December 2017, the soil radon gas was mainly influenced by temperature variations and almost the same pattern was observed for the months of January and February with additional impact coming from pressure. The current study findings can be used as an indicator for some applications, viz., seismic activity, location of subsurface faults, indoor radon concentration and uranium exploration. [ABSTRACT FROM AUTHOR]

The exact underlying mechanisms of muscle power and strength diurnal variation are not elucidated yet. The purpose of this study was to examine the time-of-day effects on electromyographic (EMG) parameters changes during a single leg drop jump (SLDJ) in male and female athletes. Forty athletes (20 males and 20 females) performed an SLDJ at 07–08°° and 17–18°° on the same day. Surface EMG activities were recorded in the Vastus lateralis, rectus femoris, Tibialis anterior and Peroneus longus muscles throughout the SLDJ test. The root-mean-square (RMS) and mean-power-frequency (MPF) were calculated. The SLDJ performance test (18.83 ± 7.13 vs 19.72 ± 7.06 cm; p = 0.017; dz = 0.13) increased significantly from morning to evening; however, EMG activities for these muscles activity (p > 0.05) has not presented a diurnal variation. [ABSTRACT FROM AUTHOR]

Gait is one of the most basic movements, and walking activity accomplished in dual task conditions realistically represents daily life mobility. Much is known about diurnal variations of gait components such as muscle power, postural control, and attention. However, paradoxically only little is known about gait itself. The aim of this study was to analyze whether gait parameters show time-of-day fluctuation in simple and dual task conditions. Sixteen young subjects performed sessions at five specific hours (06:00, 10:00, 14:00, 18:00 and 22:00 h), performing a single (walking or counting) and a dual (walking and counting) task. When performing gait in dual task conditions, an additional cognitive task had to be carried out. More precisely, the participants had to count backwards from a two-digit random number by increments of three while walking. Spatio-temporal gait parameters and counting performance data were recorded for analysis. Walking speed significantly decreased, while stride length variability increased when the task condition switched from single to dual. In the single-task condition, diurnal variations were observed in both walking speed and counting speed. Walking speed was higher in the afternoon and in the evening (14:00 and 22:00 h) and lower in the morning (10:00 h). Counting speed was maximum at 10:00 and 14:00 h and minimum at 18:00 h. Nevertheless, no significant diurnal fluctuation was substanytiated in the dual task condition. These results confirm the existing literature about changes in gait between single and dual task conditions. A diurnal pattern of single-task gait could also be highlighted. Moreover, this study suggests that diurnal variations faded in complex dual task gait, when the cognitive load nearly reached its maximum. These findings might be used to reduce the risk for falls, especially of the elderly. [ABSTRACT FROM AUTHOR]

This study aimed to assess the effects of different types of stretching on the diurnal variations of the agility performance. Twenty elite young soccer players (age: 17.40 ± 0.94 years) completed the T-test agility, either after static stretching (SS), dynamic stretching (DS), and no-stretching (NS) protocols at two times of the day (morning: 07:00 h-8:30 and evening: 17:00–18:30h), with a minimum of 2 days between testing sessions. The DS group produced significantly faster times on the agility test (9.65 ± 0.05s) in comparison to both the SS group (9.88 ± 0.042s, p< 0.01) and NS group (9.80±0.046s, p<0.01), in the morning. In addition, differences between groups revealed significant difference in the evening with a better result produced after DS (9.37 ± 0.052s in comparison to both SS group(9.70 ± 0.49s (p<0.01) and NS group (9.69 ± 0.43s, p < 0.010).The improvement of performance after (DS) compared to (NS) was significantly faster in the evening than the morning with a greater improvement at 17:00 h compared to 7:00 h (4.26 ± 2.81%vs1.78 ± 0.65%; p<0.01). Results support the use of DS affects the typical diurnal variations of agility performance either in the morning or in the evening and helps to counteract the physiological decrease in morning value. [ABSTRACT FROM AUTHOR]

The lack of standardization of methods and procedures have hindered agreement in the literature related to time-of-day effects on repeated sprint performance and needs clarification. Therefore, the aim of the present study was to investigate and systematically review the evidence relating to time-of-day based on performance measures in repeated-sprints. The entire content of PubMed (MEDLINE), Scopus, SPORTDiscus® (via EBSCOhost) and Web of Science was searched. Only experimental research studies conducted in male adult participants aged ≥18yrs, published in English before June 2019 were included. Studies assessing repeated-sprints between a minimum of two time-points during the day (morning versus evening) were deemed eligible. The primary search revealed that a total of 10 out of 112 articles were considered eligible and subsequently included. Seven articles were deemed strong and three moderate quality. Eight studies found repeated-sprint performance across the first, first few, or all sprints, to increase in favor of the evening. The magnitude of difference is dependent on the modality and the exercise protocol used. The non-motorized treadmill established an average 3.5–8.5% difference in distance covered, average and peak velocity, and average power, across all sprints in three studies and in peak power in two studies. In cycling, power output differed across all sprints by 6.0% in one study and 8.0% for the first sprint only in five studies. All four studies measuring power decrement values (i.e. rate of fatigue) established differences up to 4.0% and two out of five studies established total work to be significantly higher by 8.0%. Repeated-sprint performance is affected by time-of-day with greater performance in the late/early afternoon. The magnitude is dependent on the variable assessed and the mode of exercise. There is a clear demand for more rigorous investigations which control factors that specifically relate to investigations of time-of-day and are specific to the sport of individuals. [ABSTRACT FROM AUTHOR]

Ergonomists measure height loss in relation to loads imposed on the spine. It is difficult to interpret whether height loss responses recorded on different days are accurate due to natural daily fluctuations in height loss and measurement variability. The objective of this research was to investigate whether the variability of height loss in the sitting position is affected by time of day and to analyse day-to-day variability in asymptomatic participants. Fifty asymptomatic participants attended two sessions (morning and afternoon) of stadiometry testing on four separate days. The results showed that a variability of height loss response changes in excess of 0.886 mm in morning and 1.128 mm in afternoon between days indicates that an intervention itself has influenced height loss. Future investigations on height loss in sitting should take these results into consideration to confidently state that an intervention has influenced height loss response at each time of day. Practitioner summary: Daily fluctuation creates difficulties when interpreting whether height losses recorded on different days and times are intervention related. Seated stadiometry measures on different days and times of day demonstrated specific levels of natural variation. Changes above 0.886 mm (morning) and 1.128 mm (afternoon) can be attributed to intervention effects. Abbreviations: LBP: low back pain; SEM: standard error of measurement; MeanSDs: means of standard deviations [ABSTRACT FROM AUTHOR]

We investigated the association between the period of exposure and changes in urinary excretion of chromium and nickel among rotating shift workers in a stainless-steel plant. The study participants were composed of two groups: the workers who were occupationally exposed to metals ("exposed group") and those who were not occupationally exposed to metals ("unexposed group"). The exposed and unexposed groups consisted of 56 and 40 male rotating shift workers, respectively. Urine samples were collected immediately before and immediately after the day shift, evening shift, and night shift. Urinary chromium and nickel were measured using inductively coupled plasma mass spectrometry. To correct for variations in urine dilution, urinary metal concentrations were expressed as a ratio to urinary creatinine concentration. In the exposed group, post-shift urinary excretion of chromium was significantly higher than pre-shift excretion. However, although urinary chromium excretion clearly increased after the day and night shift [63% (p <.0001) and 87% (p <.0001), respectively], urinary chromium excretion after the evening shift was only slightly higher than that measured before the evening shift (8%, p =.028). Similar patterns were found for urinary nickel excretion (p =.0001, 0.20, and 0.18 for the day, evening, and night shifts, respectively). Non-uniform urinary excretion of metals between the day shift, evening shift, and night shift were observed in the exposed group; specifically, urinary metal excretion increased only slightly during the evening shift. In the unexposed group, no significant increase or decrease was found in median urinary chromium or nickel excretion (p=.63–0.87). Work shift-specific permissible exposure level would be necessary. [ABSTRACT FROM AUTHOR]

We aimed to investigate the effect of play at recess on diurnal fluctuations of the ability to refocus cognitively on pupils aged 11–12 years. Twenty-seven volunteer children (age = 12 ± 0.6 years) performed two test-sessions at 09:45, 10:15, 14:45 and 15:15 h. Each two test-sessions were separated by a recess (with or without motor activity). During each session, oral temperature, the reaction time (RT) and constant attention (CA) were measured. The results demonstrated that Δ-changes in core temperature, CA and RT demonstrated a significant effect of type of activity, no significant effect of time of day and no significant interaction between the type of activity and the time of day. Therefore, play at recess improves the children's abilities to regenerate cognitive performance independent of the time of the day. [ABSTRACT FROM AUTHOR]

A vital component of fire detection from remote sensors is the accurate estimation of the background temperature of an area in fire's absence, assisting in identification and attribution of fire activity. New geostationary sensors increase the data available to describe background temperature in the temporal domain. Broad area methods to extract the expected diurnal cycle of a pixel using this temporally rich data have shown potential for use in fire detection. This paper describes an application of a method for priming diurnal temperature fitting of imagery from the Advanced Himawari Imager. The BAT method is used to provide training data for temperature fitting of target pixels, to which thresholds are applied to detect thermal anomalies in 4 μm imagery over part of Australia. Results show the method detects positive thermal anomalies with respect to the diurnal model in up to 99% of cases where fires are also detected by Low Earth Orbiting (LEO) satellite active fire products. In absence of LEO active fire detection, but where a burned area product recorded fire-induced change, this method also detected anomalous activity in up to 75% of cases. Potential improvements in detection time of up to 6 h over LEO products are also demonstrated. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this study was to assess the effect of Ramadan fasting on choroidal thickness (CT) and its associated diurnal variations using spectral domain optic coherence tomography. Materials and Methods: Ocular measurements were performed on a single eye of 87 healthy individuals. Eyes were evaluated twice a day around 8.00 a.m. and 4.00 p.m. during Ramadan. Evaluations were repeated at the same time of the day, 1 month following Ramadan on the same subjects. Measurements of choroidal and retinal thickness were performed at central, temporal and nasal segments. Results: The comparison of measurements revealed that temporal CT at 8.00 a.m. and foveal, temporal and nasal CTs at 4.00 p.m. were significantly reduced during fasting (p values were 0.005, <0.001, 0.001 and 0.046, respectively). Mean changes of CTs during fasting were 14.76 ± 16.01, 9.90 ± 19.57 and 8.10 ± 16.81 µm at the fovea, temporal and nasal segments, respectively. However, CTs at non-fasting conditions were measured as 6.13 ± 12.93, 3.78 ± 15.23 and 5.05 ± 13.60 µm, respectively. In comparison, diurnal variations of foveal and temporal CTs during fasting were significantly higher than the controls (p values were <0.001 and 0.004, respectively). Additionally, retinal thicknesses during fasting were significantly reduced compared to the controls in all segments measured at 4.00 p.m. (p for all values <0.05) Conclusions: The results of the present study revealed that fasting and dehydration caused a reduction of the choroidal and retinal thicknesses. Likewise, they are also responsible for the increased diurnal variation of CTs. Therefore, early hours of the day may be preferred to evaluate retinal and choroidal thicknesses during Ramadan to avoid the effects of dehydration on the measurement results. [ABSTRACT FROM AUTHOR]

The purpose of this study was to examine the time-of-day effects on the offensive capability and aerobic performance in football game in young subjects. In a randomized order, participants realized the Yo-Yo intermittent recovery test in two test sessions and a football game situations (two 15-min games), interspersed by a verbalization sequence (3 min) at 08:00 and 17:00 h on separate days. A recovery period of 24 h was permitted between two consecutive test sessions. The results revealed diurnal variations on the maximal aerobic velocity during the Yo-Yo test (MAV) and the oral temperature with higher values in the afternoon than morning (p < 0.05). Concerning offensive capability, the numbers of scored goals were significantly higher at 17:00 h in comparison with 08:00 h (p < 0.05). However, there was no significant difference between 08:00 and 17:00 h for the kicked balls (shooting parameter). In conclusion, our findings suggest that performance was improved in the evening and the parameters (shooting and Scored goals) can be used as a model to describe the offensive capacity in football game depending on the time of day. [ABSTRACT FROM AUTHOR]

We have investigated the effects that sleep restriction (3-h sleep during two consecutive nights) have on an evening (17:00 h) submaximal weightlifting session; and whether this performance improves following a 1-h post-lunch powernap. Fifteen resistance-trained males participated in this study. Before the experimental protocol commenced, 1RM bench press and inclined leg press and normative habitual sleep were recorded. Participants were familiarised with the testing protocol, then completed three experimental conditions with two nights of prescribed sleep: (i) Normal (N): retire at 23:00 h and wake at 06:30 h, (ii) partial sleep-deprivation (SD): retire at 03:30 h and wake at 06:30 h and (iii) partial sleep-deprivation with nap (SDN): retire at 03:30 h and wake at 06:30 h with a 1-h nap at 13:00 h. Each condition was separated by at least 7 days and the order of administration was randomised and counterbalanced. Rectal (Trec) and mean skin (Ts) temperatures, Profile of Mood Scores, subjective tiredness, alertness and sleepiness values were measured at 08:00, 11:00, 14:00 and 17:00 h on the day of the weightlifting session. Following the final temperature measurements at 17:00 h, participants completed a 5-min active warm-up before a 'strength' protocol. Participants performed three repetitions of right-hand grip strength, then three repetitions at each incremental load (40%, 60% and 80% of 1RM) for bench press and inclined leg press, with a 5-min recovery in between each repetition. A linear encoder was attached perpendicular to the movement, to the bar used for the exercises. Average power (AP), average force (AF), peak velocity (PV), distance (D) and time-to-peak velocity (tPV) were measured (MuscleLab software) during the concentric phase of the movements for each lift. Data were analysed using general linear models with repeated measures. The main findings were that SD reduced maximal grip (2.7%), bench press (11.2% AP, 3.3% AF and 9.4% PV) and leg press submaximal values (5.7% AP) with a trend for a reduction in AF (3.3% P = 0.06). Furthermore, RPE increased for measures of grip strength, leg and bench press during SD. Following a 1-h powernap (SDN), values of grip and bench press improved to values similar in N, as did tiredness, alertness and sleepiness. There was a main effect for "load" on the bar for both bench and leg press where AP, AF, tPV values increased with load (P < 0.05) and PV decreased from the lightest to the heaviest load for both bench and leg press. An interaction of "load and condition" was present in leg press only, where the rate of change of AP is greater in the N than SD and SDN conditions. In addition, for PV and tPV the rate of change was greater for SDN than N or SD condition values. In summary, SD had a negative effect on grip strength and some components of bench and inclined leg press. The use of a 1-h power nap that ended 3 h before the "strength" assessment had a positive effect on weightlifting performance, subjective mood and ratings of tiredness. [ABSTRACT FROM AUTHOR]

Diurnal rhythm complicates the acquisition of clinical laboratory samples by adding a predictable time-dependent component to the pre-analytical variation that, if not taken into account, degrades the clinical utility of results on certain analytes. Here we performed a systematic review of the literature and identified, in 56 publications that met our minimum inclusion criteria, 30 analytes that undergo diurnal variation. We graded the quality of evidence of these publications using a 3-tier scoring system of our own formulation. The rigor of the experimental design and agreement varied considerably across studies. Analyte concentration oscillated considerably over the 24-h day-night cycle. The median zenith-to-nadir change relative to the nadir concentration (%ZNC) for the 30 analytes was 100%. To set the magnitude of diurnal variation into perspective, we assessed the fluctuation in analyte concentration throughout the 24-h period (diurnal variation (%CVdv)) relative to the day-to-day fluctuation determined at a fixed time during the 24-h period (within-subject biological variation (%CVw)). Then we divided the %CVdv by the published %CVw to obtain a novel metric termed the diurnal variation index (DVI). The median DVI for the 16 analytes examined was 2.0, underscoring that, for most analytes, the diurnal variation was larger than the published %CVw and highlighting the importance of adhering to protocols regulating the time of sampling when dealing with these analytes. Given that the %CVw is the basis of the reference change value (RCV) and several quality metrics such as the Sigma metric (based on total allowable error), failure to regulate the time of sample collection will compromise these %CVw-based targets. We also provide examples where failure to regulate the time of collection of diurnally changing analytes compromises their diagnostic utility. Nevertheless, for the most part, websites of major laboratories in the USA and Europe do not consistently stipulate collection at specified time junctures for the majority of the analytes identified here. [ABSTRACT FROM AUTHOR]

There is growing evidence for combined chronotherapeutic interventions as adjunctive treatments for major depression. However, as the treatments can be demanding, we need to identify predictors of response. This study aimed to describe predictors of response, remission and deterioration in the short-term phase, as well as predictors of long-term response. The predictors investigated were gender, type of depression, severity of depression, treatment resistance, quetiapine use, general self-efficacy, educational level and positive diurnal variation. Follow-up data from 27 inpatients with moderate-to-severe depression participating in a chronotherapeutic intervention were analysed. As a supplement to standard treatment, they completed 3 wake therapy sessions in the first week, 30 min daily light treatment and sleep-time stabilisation in the entire 9-week study period. Patients had a significant decrease of depressive symptoms during the first 6 days measured by HAM-D6. At Day 6, 41% of the patients responded to the treatment and 19% fulfilled the criteria of remission. Deterioration by the end of wake therapy sessions was however not uncommon. In the short-term phase, mild degree of treatment resistance was associated with remission and low educational level associated with deterioration. Positive diurnal variation (mood best in the evening) was a predictor of both short-term and long-term response to combined wake and light therapy. Furthermore, patients with evening chronotypes (measured with morningness-eveningness score) were more responsive. Our results suggest that targeting the combined chronotherapeutic intervention at patients with positive diurnal variation and evening types is a viable option. [ABSTRACT FROM AUTHOR]

Dawn is a critical period for vocal displays in songbirds. At dawn, songbirds intensify their vocalisations, for example increasing their singing rates in response to increased intruder pressure at this time, and for mate guarding. However, little is known about diurnal variations in song complexity, a sexually selected vocal trait associated with mate choice and territorial defence. We compared song complexity in 17 territorial male Tui (Prosthemadera novaeseelandiae) between dawn, solar noon and dusk. In addition, we investigated whether song complexity correlated directly with rival intrusion rate. Our results indicated that song complexity and intrusion rate were significantly higher at dawn than dusk. Analyses also suggested that higher entropy (spectral complexity) and syllable rate, in addition to shorter song duration, were associated with reduced intrusion rate into the singer’s territory. Males with higher song complexity may be perceived as stronger competitors and therefore would attract lower rival intrusion. Our study presents evidence of both diurnal changes in Tui song complexity and associations between song complexity and intrusion rate. These findings support the theory that dawn is important for songbird vocal communication in terms of territory assertion. [ABSTRACT FROM AUTHOR]

The postexercise urine lactate concentration is a novel valid exercise biomarker, which has exhibited satisfactory reliability in the morning hours under controlled water intake. The aim of the present study was to investigate the diurnal variation of the postexercise urine lactate concentration and its reliability in the afternoon hours. Thirty-two healthy children (11 boys and 21 girls) and 23 adults (13 men and 10 women) participated in the study. All participants performed two identical sessions of eight 25 m bouts of maximal freestyle swimming executed every 2 min with passive recovery in between. These sessions were performed in the morning and afternoon and were separated by 3–4 days. Adults performed an additional afternoon session that was also separated by 3–4 days. All swimmers drank 500 mL of water before and another 500 mL after each test. Capillary blood and urine samples were collected before and after each test for lactate determination. Urine creatinine, urine density and body water content were also measured. The intraclass correlation coefficient was used as a reliability index between the morning and afternoon tests, as well as between the afternoon test and retest. Swimming performance and body water content exhibited excellent reliability in both children and adults. The postexercise blood lactate concentration did not show diurnal variation, showing a good reliability between the morning and afternoon tests, as well as high reliability between the afternoon test and retest. The postexercise urine density and lactate concentration were affected by time of day. However, when lactate was normalized to creatinine, it exhibited excellent reliability in children and good-to-high reliability in adults. The postexercise urine lactate concentration showed high reliability between the afternoon test and retest, independent of creatinine normalization. The postexercise blood and urine lactate concentrations were significantly correlated in all cases, attesting to the validity of urine lactate as an index of anaerobic metabolism. We conclude that urine lactate, after normalization to creatinine, could be used in training practice either in the morning or in the afternoon. Further research is needed to assess the applicability of this novel exercise biomarker. [ABSTRACT FROM PUBLISHER]

High solar radiation has been recognised as a contributing factor to exertional heat-related illness in individuals exercising outdoors in the heat. Although solar radiation intensity has been known to have similar time-of-day variation as body temperature, the relationship between fluctuations in solar radiation associated with diurnal change in the angle of sunlight and thermoregulatory responses in individuals exercising outdoors in a hot environment remains largely unknown. The present study therefore investigated the time-of-day effects of variations in solar radiation associated with changing solar elevation angle on thermoregulatory responses during moderate-intensity outdoor exercise in the heat of summer. Eight healthy, high school baseball players, heat-acclimatised male volunteers completed a 3-h outdoor baseball trainings under the clear sky in the heat. The trainings were commenced at 0900 h in AM trial and at 1600 h in PM trial each on a separate day. Solar radiation and solar elevation angle during exercise continued to increase in AM (672–1107 W/m2and 44–69°) and decrease in PM (717–0 W/m2and 34–0°) and were higher on AM than on PM (bothP < 0.001). Although ambient temperature (AM 32–36°C, PM 36–30°C) and wet-bulb globe temperature (AM 31–33°C, PM 34–27°C) also continued to increase in AM and decrease in PM, there were no differences between trials in these (bothP > 0.05). Tympanic temperature measured by an infrared tympanic thermometer and mean skin temperature were higher in AM than PM at 120 and 180 min (P < 0.05). Skin temperature was higher in AM than PM at the upper arm and thigh at 120 min (P < 0.05) and at the calf at 120 and 180 min (bothP < 0.05). Body heat gain from the sun was greater during exercise in AM than PM (P < 0.0001), at 0–60 min in PM than AM (P < 0.0001) and at 120–180 min in AM than PM (P < 0.0001). Dry heat loss during exercise was greater at 0–60 min (P < 0.0001), and lower at 60–120 min (P < 0.05) and 120–180 min (P < 0.0001) in AM than PM. Evaporative heat loss during exercise was greater in PM than AM at 120–180 min (P < 0.0001). Total (dry + evaporation) heat loss at the skin was greater during exercise in PM than AM (P < 0.0001), at 0–60 min in AM than PM (P < 0.0001) and at 60–120 and 120–180 min in PM than AM (P < 0.05 and 0.0001). Heart rate at 120–150 min was also higher in AM than PM (P < 0.05). Neither perceived thermal sensation nor rating of perceived exertion was different between trials (bothP > 0.05). The current study demonstrates a greater thermoregulatory strain in the morning than in the afternoon resulting from a higher body temperature and heart rate in relation to an increase in environmental heat stress with rising solar radiation and solar elevation angle during moderate-intensity outdoor exercise in the heat. This response is associated with a lesser net heat loss at the skin and a greater body heat gain from the sun in the morning compared with the afternoon. [ABSTRACT FROM PUBLISHER]

This study aimed to investigate the effect of air pollution on diurnal variation of performance in anaerobic tests, cardiovascular and hematological parameters, and blood gases on soccer players following the Yo–Yo Intermittent Recovery Test Level-1 (YYIRT1). In a randomized order, 11 healthy soccer players (mean age: 21.8 [range: 20–24] years; height: 178.00 [range: 1.64–1.83] cm; body mass index [BMI]: 23.57 [range: 20.45–28.03] kg.m−2) performed a YYIRT1 at two different times of day (TOD) (08:00 h and 18:00 h) in two areas (i.e. polluted (PA) and non-polluted (NPA)) with a recovery period of ≥ 72 h in between, to determine the maximal oxygen uptake (VO2max). In each test session: resting oral temperature is measured, anaerobic performances (pre- and post-YYIRT1) were performed, cardiovascular parameters and blood samples were collected at: rest, 3 min and 60 min after the YYIRT1, to assess blood gases and hematological parameters. Our results showed that, agility performance, VO2max, red blood cells (RBC), hemoglobin (Hb), pH, and bicarbonate levels (HCO3−) decrease significantly (p < 0.001) following the YYIRT1 in PA compared to NPA. Likewise, the heart rate (HR), systolic blood pressure (SBP), platelets (PLT), white blood cells (WBC), neutrophiles (NEUT), lymphocytes (LYM), and partial pressure of CO2 levels (PvCO2) were significantly higher (p < 0.001) in PA. This effect was slightly accentuated at 18:00 h for some parameters (i.e. Agility, HCO3−, HR, PvCO2, RBC, SBP). However, performances of sprint and Sargent jump test (SJT), oral temperature, rate of perceived exertion scales (RPE), partial pressure of O2 (PvO2), diastolic blood pressure (DBP), and monocytes (MON) were not affected by pollution (p > 0.05). In conclusion, pollution seems to be critical for health stability and performance in response to YYIRT1 especially in the evening and the winter season. Therefore, coaches and athletes should draw attention to the potential importance of land use planning in their training sessions and competitions in the morning in polluted area to minimize the risk of pollution exposure. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the effect of electrostimulation strength training (ES) and time-of-day on immune response and anaerobic performances during short-term maximal exercise. In randomized order, 24 active men divided into three groups: MTG (n=8): training times 07:00–08:00h; ETG (n=8): training times 17:00–18:00h; and CG (n=8) and were asked to perform a 30-s Wingate test (i.e. peak (PP), mean (MP)) and strength (1-RM) before (T0) and after four weeks of training (T1) at 08:00h and 18:00h. Our results showed that oral temperature, PP (p<0.05), MP (p<0.05), and Interleukine-6 levels (IL-6) (p<0.001) were significantly higher at 18:00h compared to 08:00h in all groups. However, 1-RM was not affected by the time-of-day (p>0.05). Likewise, IL-6 increased after exercise at T0 and T1 in CG, ETG, and MTG (p<0.001). Moreover, ES training leads an improvement in performances (p<0.05) with an increase in the tight circumference for the MTG (p<0.01) at the same time-of-training (08:00h) without affecting the immune response (p>0.05). In fact, the amplitude of variation was disappeared in MTG after ES. However, the ES did not affect the PP, MP, and 1-RM in ETG with no change in the tight circumference. A significant increase in IL-6 at the same time-of-training (p<0.05) was observed on ETG. For CG, no significant change was observed after ES compared with pre-training. In conclusion, ES training in the morning is a potent strategy to counteract the decrease in anaerobic performances without affecting inflammatory response compared to the evening training. [ABSTRACT FROM AUTHOR]

Arbuscular mycorrhizal fungi (AMF) play a key role in soil carbon storage and release; however, they have never been considered as a factor affecting methane (CH4) emissions from rice paddies. To reveal the role of AMF, the diurnal variations of CH4emissions from the noninoculated and inoculated rice field plots were compared at midseason drainage, reflooding stage, and end-of-season drainage. The results showed that the diurnal variation patterns in the two treatments both closely tracked soil water content at midseason drainage and end-of-season drainage, while correlated very well with the stomatal conductance of rice at reflooding stage. There were no significant differences between treatments in soil water content and stomatal conductance. However, the diurnal CH4emission fluxes at the three stages ranged from 4.8 to 39.3, 0.9 to 12.4, and 0.2 to 2.3 mg m−2h−1in the noninoculated plots, and those in the inoculated plots ranged from 2.1 to 18.7, 0.9 to 5.0, and 0.3 to 1.2 mg m−2 h−1. The significant differences resulted from carbon-to-nitrogen ratios (C:N) of the noninoculated and inoculated soil, which had a negative linear correlation with maximum diurnal CH4fluxes. Compared with the noninoculated treatment, inoculating with AMF significantly increased soil C:N by improving the dry matter of rice, which intensified N limit for CH4production. [ABSTRACT FROM PUBLISHER]

Previous studies consistently reported a diurnal variation in the occurrence of intracerebral hemorrhage (ICH), with a morning peak. However, limited knowledge exists on the circadian pattern of ICH severity and outcome. This study aimed to determine possible associations between ICH onset time and admission severity and 90-day outcomes using the combined data set of the pilot and main-phase Intensive blood pressure (BP) reduction in an acute cerebral hemorrhage trial (INTERACT). The ICH onset time was categorized into three groups (1: 00:00–07:59; 2: 08:00–15:59; and 3: 16:00–23:59). We found an association between onset time and low Glasgow Coma Scale score: aOR (time 1: 1.72, 95% CI 1.12–2.66; time 3: 1.95, 95% CI 1.31–2.89,p= 0.003; in comparison to time 2). There was no association between onset time and volume of ICH (adjustedp= 0.354) or 90-day outcomes of death or major disability, and death and major disability separately (all adjustedp> 0.4). The results showed that more severe cases of ICH patients, defined by a reduced level of consciousness, had late afternoon to early morning stroke onset, but this was unrelated to baseline hematoma volume or location. There was no circadian influence on ICH clinical outcome. [ABSTRACT FROM PUBLISHER]

Aporphine alkaloids are secondary metabolites that are obtained in low levels from species of the Annonaceae family. Nitrogen addition may increase the alkaloid content in plants. However, previous studies published did not consider that nitrogen could change the alkaloid content throughout the day. We conducted this short-term study to determine the effects of nitrogen applied throughout the diurnal period on the aporphine alkaloids via measurements conducted on the roots, stems and leaves ofAnnona diversifoliaseedlings. The 60-day-old seedlings were cultured with the addition of three levels of nitrogen (0, 30 and 60 mM), and alkaloid extracts were analysed using high-performance liquid chromatography. The highest total alkaloid content was measured in the treatment with moderate nitrogen supply. Further, the levels of aporphine alkaloids changed significantly in the first few hours of the diurnal period. We conclude that aporphine alkaloid content increased with moderate nitrogen supply and exhibited diurnal variation. [ABSTRACT FROM PUBLISHER]

The aim of this study was to examine the effects of training at the same time of day on diurnal variations of technical ability and swimming performance, to provide some recommendations with regard to adjusting training hours in accord with the time of day of competitive events. Eighteen participants volunteered for this study, and these were randomly assigned to either a morning training group (MTG, who trained only between 07:00 and 08:00 h,n = 6), an evening training group (ETG, who trained only between 17:00 and 18:00 h,n = 6), or a control group (CG, did not train but participated in all tests,n = 6). Swimming performance and technical ability – (i) stroke parameters: swim velocity (V), stroke rate (SR), and stroke length (SL); and (ii) motor organization: arm stroke phases and arm coordination (Idc) – were recorded 2 weeks before and 2 weeks after an 8-week regular training period. For all participants, the morning and evening tests were scheduled at the same time of day as the morning and evening training sessions. After training, the major finding of this study was that both ETG and the CG showed significantly lowerP,V, SR, phase (B), phase (C), and Idc values in the morning than in the evening. However,P,V, SR, phase (B), phase (C), and Idc of the MTG measured at 07:00 and 17:00 h did not differ. Thus, training at a specific time of day increased performance in MTG at this time and modified the diurnal variation of swim performance. This study indicates that training at a specific time of day can result in marked changes in both swimming performance and technical aspects of swimming. Furthermore, training in the morning improved morning swimming performance and its components, and the amplitude of the morning–evening difference decreased. Training in the evening improved swimming performance and its components more in the evening than the morning, and the amplitude of the morning–evening difference increased. [ABSTRACT FROM AUTHOR]

The purpose of this study was to examine time-of-day effects on short-term performance in obese young men. In a balanced study design, 30 boys were divided into two groups: obese (OG;n = 15) and non-obese (CG;n = 15) groups. Both groups performed anaerobic tests of strength and power (squat-Jump, SJ; counter-movement jump, CMJ; 10-m sprint; and 30-m sprint) at 08:00 and 17:00 h on separate days. The results showed morning–evening differences in all variables in CG, with significant increases at 17:00 h (around the time of peak temperature) in comparison with 08:00 h (p < 0.01) for OG. However, such morning-evening differences were not found in the OG, except for the 30-m sprint. Obesity affects the diurnal variation on performances of 30-m sprint with a significant decrease in the evening for OG of 1.23% (p < 0.01). A correlation between anaerobic performance and oral temperature was observed only in the 30-m sprint test. In conclusion, the findings of the present study indicated that obesity is a problem that can affect circadian rhythms and performance in obese young men; therefore, preventing childhood obesity should become a top priority in efforts to improve performance and health. [ABSTRACT FROM AUTHOR]

Context: Professional ski waxers are exposed to particulate matter (PM) during work, but little is known about untoward pulmonary effects. Objectives: The aim was to study lung function and pneumoproteins in professional ski waxers before and during exposure to PM generated during ski waxing and ski preparation. Material and methods: Forty-five male professional ski waxers examined on an exposure-free day in the morning and at least 6 h later were re-examined during ski waxing 2 d later in a cross-shift study. Pulmonary function and gas diffusion capacity were measured and Clara cell protein 16 (CC-16), surfactant protein A and D (SP-A and SP-D), and C-reactive protein (CRP) were determined in serum. PM was collected by personal sampling. Results: The mean PM concentrations in the respirable and in the inhalable aerosol fraction in air samples collected during waxing were 3.1 mg/m3 and 6.2 mg/m3, respectively. The mid expiratory flow (MEF75%) was significantly lower during exposure. The concentrations of CRP increased significantly by more than 100% during ski waxing, and SP-D and CC-16 were significantly lower during the exposed day as compared with the non-exposed day. The results further suggest that SP-D and CC-16 in serum are affected by diurnal variations. No significant alterations were observed for the lung diffusion capacity. Discussion and conclusions: The results suggest that exposure to PM generated during ski waxing may induce pulmonary inflammation with reduced flow in small airways. The increased CRP concentrations indicate the induction of systemic inflammation in ski waxers during exposure. [ABSTRACT FROM AUTHOR]

Heart rate (HR) recovery (HRR) and variability (HRV) after exercise are non-invasive tools used to assess cardiac autonomic regulation and cardiovascular prognosis. Autonomic recovery is slower after evening than morning exercise in healthy individuals, but this influence is unknown in subjects with autonomic dysfunction, although it may affect prognostic evaluation. This study compared post-exercise HRR and HRV after maximal morning and evening exercise in pre-hypertensive men. Ten volunteers randomly underwent two maximal exercise tests conducted in the morning (8–10 a.m.) and evening (6–8 p.m.). HRR60s (HR reduction at 60 s of recovery – prognostic index), T30 (short-term time-constant of HRR – parasympathetic reactivation marker), rMSSD30s(square root of the mean of the sum of the squares of differences between adjacent R–R intervals on subsequent 30 s segments – parasympathetic reactivation marker), and HRRτ (time constant of the first order exponential fitting of HRR – marker of sympathetic withdraw and parasympathetic reactivation) were measured. Pairedt-test and two-way ANOVA were used. HRR60s and HRRτ were similar after exercise in the morning and evening (27 ± 7 vs. 29 ± 7 bpm,p = 0.111, and 79 ± 14 vs. 96 ± 29 s,p = 0.119, respectively). T30 was significantly greater after evening exercise (405 ± 215 vs. 295 ± 119 s,p = 0.002) and rMSSD30swas lower in the evening (main factor session,p = 0.009). In conclusion, in pre-hypertensive men, the prognostic index of HRR, HRR60s, is not affected by the time of day when exercise is conducted. However, post-exercise parasympathetic reactivation, evaluated by T30 and rMSSD30s, is blunted after evening exercise. [ABSTRACT FROM PUBLISHER]

The aim of this study was to investigate the effect of an Olympic-Weightlifting-session followed by 48-h recovery period on the oxidative and antioxidant parameters’ diurnal variation. Nine weightlifters (21 ± 0.5 years) performed, in randomized order, three Olympic-Weightlifting-sessions at 08 h:00, 14 h:00 and 18 h:00. Blood samples were collected: at rest and 3 min and 48 h after each session. C-reactive protein (CRP), rate of lipid peroxidation and antioxidant activities were assessed. At rest, analysis of variance showed a significant time of day (TOD) effect (p < 0.05) for uric acid, catalase and glutathione peroxidase with higher values at 14 h:00 and 18 h:00 compared with 08 h:00. However, no significant TOD effect for malondialdehyde, total bilirubin and CRP was observed. Given the profound changes (p < 0.001) in the post-training session values, these diurnal variations have been altered immediately and even 48 h after the training sessions. Despite the significant decreases in the post-training values after the 48-h recovery period (p < 0.05), levels of lipid peroxidation and enzymatic defense remained elevated (p < 0.05) 48 h after the morning training session. However, after the afternoon and evening sessions, the same period was sufficient to return values to the baseline levels. In conclusion, the morning session seems to generate the most important acute and delayed lipid peroxidation responses. Therefore, weightlifting coaches should avoid scheduling their training sessions in the morning-hours. [ABSTRACT FROM AUTHOR]

Aim: To find out how, when, and why back pain causes sleep disturbance. This is the data analysis phase following a series of four literature reviews, which seek to find out whether different types of sleep disturbance can be caused by different sorts of back pain. Method: Discriminant analyses have been performed on 8 indices, 7 diagnoses, and 114 variables derived from a database of 88 clinical items collected prospectively from 1234 consultations for low back pain. Results: Difficulty getting off to sleep was essentially found to be an indication of back pain severity as shown by the correlations with PAIN index B (0.56), PAIN index A (0.47), pain visual analog scale (0.43), straight leg raising (SLR) ipselateral pain (0.40), SLR range (elevation −0.31), disability (ability −0.25), analgesic consumption yesterday (0.25), and the extent of pain down the leg (0.25). However, difficulty getting off to sleep showed some 'non-severity' aspects. It was seen relatively more in females; with direct lumbar trauma causing the first episode; and pain on resisted hip flexion. It was associated with less early morning stiffness in the back. Diagnostically it was a bit more indicative of the 'anterior column' symmetrical disc degeneration syndrome but also the 'posterior column' rotation back strain syndrome. Being awoken by back pain in the night also acted as a measure of back pain severity but not quite so effectively as difficulty getting off to sleep. Being awoken also seemed slightly more a 'posterior column' problem in the form of the facet joint syndrome, and slightly more so than rotation strain. Interestingly, being awoken was linked to asymmetry of the direction in which the feet pointed upwards when the patient was reclining. This observation probably reflects the relative degrees of rotation of opposite hips. This 'foot' aspect seemed equally linked to awakening with both pain turning and ache whilst remaining immobile. Awakening due to pain turning in bed was seen slightly more with the Facet joint syndrome. It was also linked more to being a male; with resisted hip internal rotation causing contralateral pain; with the sit up test inducing lopsided back pain; and lumbar extension standing causing unilateral pain. Awakening with ache or pain whilst immobile and remaining still was seen slightly more with S1 (and L5) prolapsed intervertebral disc (with nerve root deficit). It was also more common in females; and with resisted hip flexion painful; and lumbar flexion standing inducing bilateral back pain. Early morning stiffness in the back for an hour or more was seen more in the thoracolumbar junction level syndrome (which shows few signs in the low back). With regard to diurnal variation of back symptoms, the facet joint syndrome seemed worse in the mornings. Those worse in the afternoon, evening, or at the end of work were more often the older men; those that had the thoracolumbar syndrome who were also worse at night. Those worse at night had a sit up test that induced midline back pain; and standing lateral flexion caused less unilateral pain. This may just reflect the symmetrical disc degeneration syndrome. Discussion: All these finding will need to be replicated in further studies which could at the same time be used to explain the underlying mechanisms involved. Such understandings may well afford diagnostic insights and therapeutic benefits. [ABSTRACT FROM AUTHOR]

It has been clearly established that maximal force varies during the day in human muscles but the exact mechanisms behind the diurnal rhythms are still not fully clarified. Therefore, the aim of this study was to examine the diurnal rhythms in maximal isometric force production in a large group of participants and also by separating the high morning performance types (n = 8) and the high evening performance types (n = 19) from the neutral types (n = 45) based on their actual maximal isometric force levels. Measurements were performed in the morning (7:26 h ± 63 min) and in the evening (17:57 h ± 74 min) for maximal bilateral isometric leg press force (MVCLP) together with myoelectric activity (EMGLP), maximal unilateral isometric knee extension force (MVCKE) and maximal voluntary activation level (VA%) during maximal unilateral isometric knee extension force (MVCVA) together with myoelectric activity (EMGVA). In addition, venous blood samples were drawn four times a day and serum testosterone and cortisol concentrations were analyzed. None of the participants belonged to the extreme morning or evening chronotype according to the Munich Chronotype Questionnaire. In the total group of participants, MVCLPand MVCKEwere 4.4 ± 12.9% (p < 0.01) and 4.3 ± 10.6% (p < 0.01) higher in the evening compared to the morning. MVCVAand VA% did not show significant diurnal variation. The high morning performance types showed lower force values in the evening compared to the morning for MVCLP(10.8 ± 9.1%;p < 0.05) and MVCKE(5.7 ± 4.9%;p < 0.05). No significant diurnal variation was observed for MVCVAand VA%. The high evening performance types showed higher force values in the evening for MVCLP(16.1 ± 15.9%;p < 0.001), MVCKE(13.5 ± 11.3%;p < 0.001) and MVCVA(6.2 ± 9.9%;p < 0.05) with a concomitant higher VA% in the evening (p < 0.05). The neutral types showed significantly higher evening force values for the MVCLP(2.1 ± 6.7%;p < 0.05). All the other neuromuscular variables did not show significant diurnal variations. EMGLPand EMGVAdid not show significant diurnal fluctuations in any group. Serum testosterone and cortisol concentrations showed normal daily rhythms with higher values observed in the morning in all of the groups (p < 0.001). Between-group differences were observed for MVCLP(p < 0.001) and MVCKE(p < 0.001) between all of the three groups. Diurnal changes in VA% differed between the high evening performance types and the neutral types (p < 0.05) and the testosterone/cortisol ratio (p < 0.05) as well as vastus lateralis EMGVA(p < 0.05) differed between the high morning and high evening performance types. In conclusion, we were able to identify the high morning performance types, the high evening performance types and the neutral types who showed significantly different diurnal rhythms in force production, irrespective of their actual chronotype. Therefore, the questionnaires designed to determine the chronotype may not always be sensitive enough to determine the “morningness” or “eveningness” in maximal neuromuscular performance. In general, central factors could partially explain the diurnal fluctuations in maximal strength performance, but peripheral mechanisms were also possibly involved. [ABSTRACT FROM PUBLISHER]

The aim of this study was to investigate the performance of an Olympic-Weightlifting session training at three times of the day on the performance related to biochemical responses. Nine weightlifters (21 ± 0.5 years) performed, in randomised order, on three Olympic-Weightlifting training (snatch, clean and jerk) sessions (08:00 a.m., 02:00 p. m., 06:00 p. m.). Blood samples were collected: before, 3 min and 48 h after each training session. Haematological parameters and markers of muscle injury were assessed. Resting oral temperature and rating of perceived exertion (RPE) were also assessed during each session. ANOVA showed that the performance was better (P < 0.001) at 02:00 p. m. with a less RPE (P < 0.01) compared to the morning and the evening sessions while there was higher (P < 0.05) oral temperature at 06:00 p. m. versus 08:00 a.m. and 02:00 p. m. Muscle damage changed immediately (without significant effect after 48 h) after the training sessions with lower values ​​in the evening compared to the morning. In conclusion, the afternoon training is more effective than morning or evening sessions for weightlifters. Therefore, coaches and weightlifters should be advised to schedule their training session in the afternoon hour. [ABSTRACT FROM PUBLISHER]