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Long-term, intense endurance exercise training can occasionally induce endothelial micro-damage and cardiac fibrosis. The underlying mechanisms are incompletely understood. Twenty healthy, well-trained male participants (10 runners and 10 cyclists) performed a strenuous high-intensity interval training (HIIT) session matched by age, height, weight and maximal oxygen consumption. We assessed the acute exercise response of novel cardiac biomarkers of fibrosis [e.g., galectin-3 (Gal-3) and soluble suppression of tumorigenicity 2 (sST2)] per exercise modality and their relationship with haemodynamic contributors, such as preload, afterload and cardiac contractility index (CTi), in addition to endothelial damage by sustained activation and shedding of endothelial cells (ECs). Serum Gal-3 and sST2 concentrations were investigated by enzyme-linked immunosorbent assays; haemodynamics were analysed via impedance plethysmography and circulating ECs by flow cytometry. The Gal-3 and sST2 concentrations and ECs were elevated after exercise (P < 0.001), without interaction between exercise modalities. Circulating Gal-3 and sST2 concentrations both showed a positive relationship with ECs (r rm  = 0.68, P = 0.001 and r rm  = 0.57, P = 0.010, respectively, both n = 18). The EC association with Gal-3 was significant only in cyclists, but equally strong for both modalities. Gal-3 was also related to exercise-induced CTi (r rm  = 0.57, P = 0.011, n = 18). Cardiac wall stress is increased after an acute HIIT session but does not differ between exercise modalities. Exercise-released Gal-3 from cardiac macrophages could very probably drive systemic endothelial damage, based on an enhanced CTi. The importance of acute exercise-induced vascular resistances and cardiac contractility for the release of fibrotic biomarkers and any long-term pathological endothelial adaptation should be investigated further, also relative to the exercise modality. NEW FINDINGS: What is the central question of this study? Circulating biomarkers of cardiac wall stress and fibrosis are influenced by physical exercise. The underlying mechanisms per exercise modality are still unclear. What is the main finding and its importance? We show that galectin-3 (Gal-3) and soluble suppression of tumorigenicity 2 (sST2) are increased after acute exercise but do not differ between running and cycling. One haemodynamic contributor to the secretion of Gal-3 is an enhanced cardiac contractility. Acute exercise-released Gal-3 and sST2 are linked to sustained endothelial activation and cell shedding. This could be relevant in the context of fibrosis development and could identify athletes at risk for pathological endothelial adaptations., (© 2023 The Authors. Experimental Physiology published by John Wiley & Sons Ltd on behalf of The Physiological Society.)

Both respiratory muscle endurance training (RMET) and inspiratory resistive training (IMT) seem to increase whole-body exercise performance, but direct comparisons between the two are scarce. We hypothesized that the similarity of RMET to exercise-induced ventilation would induce larger improvements compared to IMT. Twenty-six moderately-trained men performed either 4 weeks of RMET, IMT or SHAM training. Before and after the interventions, respiratory muscle endurance, 3-km running time-trial performance and leg muscle fatigue after intense constant-load cycling (assessed with femoral nerve magnetic stimulation) were measured. Both RMET (+ 59%) and IMT (+ 38%) increased respiratory muscle endurance (both p < 0.01 vs. SHAM) but only IMT increased inspiratory strength (+ 32%, p < 0.001 vs. SHAM). 3-km time improved showing a main effect of training (p = 0.026), however with no differences between groups. Leg fatigue after cycling was not attenuated with training (p = 0.088 for group-training interaction). All groups showed a significant (~ 0.3 l) increase in average tidal volume during cycling exercise combined with a concomitant reduction in respiratory exertion. While RMET and IMT improved specific aspects of respiratory muscles performance, no benefits beyond SHAM were seen during whole-body exercise. Changes in respiratory sensations might be a result of altered breathing pattern., (© 2023. The Author(s).)

Purpose: We investigated whether a 4-wk period of respiratory muscle endurance training (RMET) or respiratory muscle sprint interval training (RMSIT) would lead to an attenuation of inspiratory muscle and quadriceps fatigue after a bout of high-intensity cycling compared with a placebo intervention (PLAT), as predicted by the respiratory metaboreflex model., Methods: Thirty-three active, young healthy adults performed RMET, RMSIT, or PLAT. Changes in inspiratory muscle and quadriceps twitches in response to a cycling test at 90% of peak work capacity were assessed before and after training. EMG activity and deoxyhemoglobin (HHb, via near-infrared spectroscopy) of the quadriceps and inspiratory muscles were also monitored during the cycling test, along with cardiorespiratory and perceptual variables., Results: At pretraining, cycling reduced the twitch force of the inspiratory muscles (86% ± 11% baseline) and quadriceps (66% ± 16% baseline). Training did not attenuate the drop in twitch force of the inspiratory muscles (PLAT, -3.5 ± 4.9 percent-points [p.p.]; RMET, 2.7 ± 11.3 p.p.; RMSIT, 4.1 ± 8.5 p.p.; group-training interaction, P = 0.394) or quadriceps (PLAT, 3.8 ± 18.6 p.p.; RMET, -2.6 ± 14.0 p.p.; RMSIT, 5.2 ± 9.8 p.p.; group-training interaction P = 0.432). EMG activity and HHb levels during cycling did not change after training for either group. Only RMSIT showed a within-group decrease in the perception of respiratory exertion with training., Conclusions: Four weeks of RMET or RMSIT did not attenuate the development of exercise-induced inspiratory or quadriceps fatigue. The ergogenic effects of respiratory muscle training during whole-body exercise might be related to an attenuation of perceptual responses., (Copyright © 2023 by the American College of Sports Medicine.)

Objectives: As females have been hypothesized to have more fatigue resistant inspiratory muscles, this study aimed to compare the development of inspiratory and leg muscle fatigue between males and females following high-intensity cycling., Design: Cross-sectional comparison., Methods: 17 healthy young males (27 ± 6 years, V̇O 2peak 55 ± 10 ml･min -1 ･kg -1 ) and females (25 ± 4 years, V̇O 2peak 45 ± 7 ml･min -1 ･kg -1 ) cycled until exhaustion at 90% of the peak power output achieved during an incremental test. Changes in quadriceps and inspiratory muscle function were assessed via maximal voluntary contractions (MVC) and assessments of contractility via electrical stimulation of the femoral nerve and cervical magnetic stimulation of the phrenic nerves., Results: Time to exhaustion was similar between sexes (p = 0.270, 95% CI -2.4 - 0.7 min). MVC of the quadriceps was lower after cycling for males (83.9 ± 11.5% vs. 94.0 ± 12.0% of baseline for females, p = 0.018). Reductions in twitch forces were not different between sexes for the quadriceps (p = 0.314, 95% CI -5.5 - 16.6 percent-points) or inspiratory muscles (p = 0.312, 95% CI -4.0 - 2.3 percent-points). Changes in inspiratory muscle twitches were unrelated to the different measures of quadriceps fatigue., Conclusion: Females incur similar peripheral fatigue in the quadriceps and inspiratory muscles compared with men following high-intensity cycling, despite smaller reduction in voluntary force. This small difference alone does not seem sufficient to warrant different training strategies to be recommended for women., Competing Interests: Declaration of Interest Statement The authors have no conflict of interest to disclose., (Copyright © 2023 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Competing Interests: Conflict of interest: none declared.

Aims: Poor sleep is a frequent occurrence in the critical illness. Evaluate sleep quality and test the effect of a multi-intervention sleep care protocol in improving sleep quality in a coronary care unit (CCU)., Methods and Results: Quasi-experimental study, carried out in two phases. During the first phase, the control group (n = 58 patients) received usual care. Baseline sleep data were collected through the Richards-Campbell Sleep Questionnaire (RCSQ) and the Sleep in the Intensive Care Unit Questionnaire (SICUQ). During the second phase (n = 55 patients), a sleep care protocol was implemented. Interventions included actions to promote analgesia, reduce noise, brightness, and other general measures. Sleep data were collected again to assess the impact of these interventions. The intervention group had better scores in overall sleep depth [median (interquartile range)] [81 (65-96.7) vs. 69.7 (50-90); P = 0.046]; sleep fragmentation [90 (65-100) vs. 69 (42.2-92.7); P = 0.011]; return to sleep [90 (69.7-100) vs. 71.2 (40.7-96.5); P = 0.007]; sleep quality [85 (65-100) vs. 71.1 (49-98.1); P = 0.026]; and mean RCSQ score [83 (66-94) vs. 66.5 (45.7-87.2); P = 0.002] than the baseline group. The main barriers to sleep were pain [1 (1.0-5.5)], light [1 (1.0-5.0)], and noise [1 (1.0-5.0)]. The most rated sources of sleep-disturbing noise were heart monitor alarm [3 (1.0-5.25)], intravenous pump alarm [1.5 (1.0-5.00)]. and mechanical ventilator alarm [1 (1.0-5.0)]. All were significantly lower in the intervention group than in the baseline group., Conclusion: A multi-intervention protocol was feasible and effective in improving different sleep quality parameters and reducing some barriers to sleep in CCU patients., (Published on behalf of the European Society of Cardiology. All rights reserved. © The Author(s) 2021. For permissions, please email: journals.permissions@oup.com.)

Objective: To investigate whether a cycling test based on decremental loads (DEC) could elicit higher maximal oxygen uptake (V˙O2max) values compared with an incremental test (INC)., Design: Nineteen well-trained individuals performed an INC and a DEC test on a single day, in randomized order., Methods: During INC, the load was increased by 20 W·min-1 until task failure. During DEC, the load started at 20 W higher than the peak load achieved during INC (familiarization trial) and was progressively decreased. Gas exchange and electromyography (EMG) activity (n = 11) from 4 lower-limb muscles were monitored throughout the tests. Physiological and EMG data measured at V˙O2max were compared between the 2 protocols using paired t tests., Results: V˙O2max during the DEC was 3.0% (5.9%) higher than during INC (range 94%-116%; P = .01), in spite of a lower power output (-21 [20] W, P < .001) at V˙O2max. Pulmonary ventilation (P = .036) and breathing rate (P = .023) were also higher during DEC. EMG activity measured at V˙O2max was not different between tests, despite the lower output during DEC., Conclusions: A DEC exercise test produces higher V˙O2max in cycling compared with an INC test, which was accompanied by higher pulmonary ventilation and similar EMG activity. The additional O2 uptake during DEC might be related to extra work performed either by the respiratory muscles and/or the less oxidatively efficient leg muscles.

Purpose: This study aimecd to investigate whether elite athletes could reach higher values of maximal oxygen uptake (V˙O2max) during a decremental exercise test in comparison with a traditional incremental test, as recently demonstrated in trained individuals., Methods: Nine male runners (age 25.8 [5.1] y, season best 10-km time 31:19 [1:50]) performed, on different days, 3 maximal uphill (5% grade) running exercise tests in fixed order: an incremental test (INC1), a V-shape exercise test (where speed started at 0.5 km·h-1 higher than the top stage finished during INC1 and was slowly decreased during 5.5 min, when it was again increased in similar fashion to the INC tests), and a final incremental test (INC2)., Results: V˙O2max during the V-shape exercise test was higher than during INC1 (6.3% [3.0%], P = .01), although running speed was lower (16.6 [1.7] vs 17.9 [1.6] km·h-1, P = .01). Performance was similar between INC1 and INC2, but V˙O2max during INC2 was higher than INC1 (P < .001). During the V-shape exercise test, 5 participants reached the incremental part of the test, but V˙O2 did not increase (ΔV˙O2=52 [259] mL·min-1, P = .67), despite higher running speed (approximately 1.1 km·h-1, P < .01). Heart rate, pulmonary ventilation, breathing rate, and respiratory exchange ratio measured at V˙O2max were not different between tests., Conclusion: A decremental exercise test of sufficient intensity can produce higher V˙O2max than a traditional incremental test, even in elite athletes, and this is maintained during a subsequent incremental test.

Objective: Massive hemoptysis is one of the most serious complications in patients with cystic fibrosis (CF). This study aimed to evaluate the hemoptysis-free period following bronchial and non-bronchial artery embolization (BAE/non-BAE) in CF patients and to investigate predictors of recurrent bleeding and mortality by any cause., Methods: This was a retrospective cohort study of CF patients ≥ 16 years of age undergoing BAE/non-BAE for hemoptysis between 2000 and 2017., Results: We analyzed 39 hemoptysis episodes treated with BAE/non-BAE in 17 CF patients. Hemoptysis recurrence rate was 56.4%. Of the sample as a whole, 3 (17.6%) were hemoptysis-free during the study period, 2 (11.8%) underwent lung transplantation, and 3 (17.6%) died. The median hemoptysis-free period was 17 months. The median hemoptysis-free period was longer in patients with chronic infection with Pseudomonas aeruginosa (31 months; 95% CI: 0.00-68.5) than in those without that type of infection (4 months; 95% CI: 1.8-6.2; p = 0.017). However, this association was considered weak, and its clinical significance was uncertain due to the small number of patients without that infection., Conclusions: BAE appears to be effective in the treatment of hemoptysis in patients with CF.

Purpose: To compare the cardiorespiratory responses of a traditional session of high-intensity interval training session with that of a session of similar duration and average load, but with decreasing workload within each bout in cyclists and runners., Methods: A total of 15 cyclists (maximal oxygen uptake [V˙O2max] 62 [6] mL·kg-1·min-1) and 15 runners (V˙O2max 58 [4] mL·kg-1·min-1) performed both sessions at the maximal common tolerable load on different days. The sessions consisted of four 4-minute intervals interspersed with 3 minutes of active recovery. Power output was held constant for each bout within the traditional day, whereas power started 40 W (2 km·h-1) higher and finished 40 W (2 km·h-1) lower than average within each bout of the decremental session., Results: Average oxygen uptake during the high-intensity intervals was higher in the decremental session in cycling (89 [4]% vs 86 [5]% of V˙O2max, P = .002) but not in running (91 [4]% vs 90 [4]% of V˙O2max, P = .38), as was the time spent >90% of V˙O2max and the time spent >90% of peak heart rate. Average heart rate (P < .001), pulmonary ventilation (P < .001), and blood lactate concentration (P < .001) were higher during the decremental sessions in both cycling and running., Conclusions: Higher levels of physiological perturbations were achieved during decremental sessions in both cycling and running. These differences were, however, more prominent in cycling, thus making cycling a more attractive modality for testing the effects of a training intervention.

Objectives: Regular physical exercise is known to protect endothelial integrity. It has been proposed that acute exercise-induced changes of the (anti-)oxidative system influence early (glycocalyx shedding) and sustained endothelial activation (shedding of endothelial cells, ECs) as well as endothelial-cell repair by circulating hematopoietic stem and progenitor cells (HPCs). However, results are not conclusive and data in trained participants performing different exercise modalities is lacking., Design: Eighteen healthy, well-trained participants (9 runners, 9 cyclists; age: 29.7 ± 4.2 yrs) performed a strenuous acute exercise session consisting of 4 bouts of 4-min high-intensity with decreasing power profile and 3-min low-intensity in-between., Methods: Average power/speed of intense phases was 85% of the peak achieved in a previous incremental test. Before and shortly after exercise, total oxidative and antioxidative capacities (TAC), shedding of syndecan-1, heparan sulfate, hyaluronan, ECs, and circulating HPCs were investigated., Results: TAC decreased from 1.81 ± 0.42 nmol/L to 1.47 ± 0.23 nmol/L post-exercise (p = 0.010) only in runners. Exercise-induced early and sustained endothelial activation were enhanced post-exercise- syndecan-1: 103.2 ± 63.3 ng/mL to 111.3 ± 71.3 ng/mL, heparan sulfate: from 2637.9 ± 800.1 ng/mL to 3197.1 ± 1416.3 ng/mL, both p < 0.05; hyaluronan: 84.3 ± 21.8 ng/mL to 121.4 ± 29.4 ng/mL, ECs: from 6.6 ± 4.5 cells/μL to 9.5 ± 6.2 cells/μL, both p < 0.01; results were not different between exercise modalities and negatively related to TAC concentrations post-exercise. HPC proportions and self-renewal ability were negatively, while EC concentrations were positively associated with circulating hyaluronan concentrations., Conclusions: These results highlight the importance of the antioxidative system to prevent the endothelium from acute exercise-induced vascular injury - independent of exercise modality - in well-trained participants. Endothelial-cell repair is associated with hyluronan signaling, possibly a similar mechanism as in wound repair., (Copyright © 2021 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.)

Purpose: To investigate whether a metabolic cart using a flowmeter in the upper range of accepted resistance to airflow (<1.5 cmH 2 O∙L -1 ∙s -1 for flows up to 14 L∙s -1 , American Thoracic Society) negatively impacts exercise performance in healthy individuals., Methods: 16 recreationally active males (age 25 ± 1 years, height 180 ± 6 cm, weight 73.5 ± 5.8 kg, all mean ± SD) performed two incremental tests on a bicycle ergometer on each of two visits, using a metabolic cart with a flowmeter of either low (Oxycon Pro) or high (Innocor) airflow resistance. Mouth pressures, gas exchange, blood lactate concentration [La - ], perception of breathlessness, respiratory, and leg exertion were assessed throughout the tests., Results: Tests performed with the Innocor were significantly shorter (15.3 ± 3.2 vs. 15.8 ± 3.3 min, p < 0.0001) and showed higher maximal flow resistance (1.3 ± 0.2 vs. 0.3 ± 0.0 cmH 2 O∙L -1 ∙s -1 , p < 0.0001). At end-exercise, peak oxygen consumption (-200 ± 220 ml.min -1 , p < 0.0001), minute ventilation (-19.9 ± 10.5 L.min -1 , p < 0.0001), breathing frequency (-5.4 ± 5.2 breaths.min -1 , p < 0.0001), heart rate (-2.1 ± 3.6 bpm, p = 0.002) and [La - ] (-0.7 ± 1.0 mmol.L -1 , p < 0.0001), but not tidal volume (-0.1 ± 0.2 L, p = 0.172) were lower with the Innocor, while the perception of breathlessness was higher (+3.8 ± 5.1 points, p < 0.0001)., Conclusions: Airflow resistance in the upper range of current guidelines can significantly affect exercise performance and respiratory pattern in young, healthy males during incremental exercise. The present results indicate the need to revisit guidelines for devices used in ergospirometry., (© 2021 The Authors. Physiological Reports published by Wiley Periodicals LLC on behalf of The Physiological Society and the American Physiological Society.)

Introduction: The chronic effects of respiratory muscle training (RMT) on the cardiovascular system remain unclear. This investigation tested to which degree a single sessions of RMT with or without added vibration, which could enhance peripheral blood flow and vascular response, or a 4-week RMT program could result in changes in pulse wave velocity (PWV), blood pressure (systolic, SBP; diastolic, DBP) and other markers of cardiovascular health., Methods: Sixteen young and healthy participants (8 m/8f) performed 15 min of either continuous normocapnic hyperpnea (RMET), sprint-interval-type hyperpnea (RMSIT) or a control session (quiet sitting). Sessions were performed once with and once without passive vibration of the lower limbs. To assess training-induced adaptations, thirty-four young and healthy participants (17 m/17f) were measured before and after 4 weeks (three weekly sessions) of RMET ( n = 13, 30-min sessions of normocapnic hyperpnea), RMSIT [ n = 11, 6 × 1 min (1 min break) normocapnic hyperpnea with added resistance] or placebo ( n = 10)., Results: SBP was elevated from baseline at 5 min after each RMT session, but returned to baseline levels after 15 min, whereas DBP was unchanged from baseline following RMT. Carotid-femoral PWV (PWV CF ) was elevated at 5 and 15 min after RMT compared to baseline (main effect of time, P = 0.001), whereas no changes were seen for carotid-radial PWV (PWV CR ) or the PWV CF /PWV C R ratio. Vibration had no effects in any of the interventions. Following the 4-week training period, no differences from the placebo group were seen for SBP ( P = 0.686), DBP ( P = 0.233), PWV CF ( P = 0.844), PWV CR ( P = 0.815) or the PWV CF /PWV CR ratio ( P = 0.389)., Discussion/conclusion: Although 15 min of RMT sessions elicited transient increases in PWV CF and SBP, no changes were detected following 4 weeks of either RMET or RMSIT. Adding passive vibration of the lower limbs during RMT sessions did not provide additional value to the session with regards to vascular responses., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2020 Beltrami, Mzee and Spengler.)

The kinetics of recovery from neuromuscular fatigue resulting from exercise time trials (TTs) of different durations are not well-known. The aim of this study was to determine if TTs of three different durations would result in different short-term recovery in maximal voluntary contraction (MVC) and evoked peak forces. Twelve trained subjects performed repetitive concentric right knee extensions on an isokinetic dynamometer self-paced to last 3, 10, and 40 min (TTs). Neuromuscular function was assessed immediately (<2 s) and 1, 2, 4, and 8 min after completion of each TT using MVCs and electrical stimulation. Electrical stimulations consisted of single stimulus (SS), paired stimuli at 10 Hz (PS10), and paired stimuli at 100 Hz (PS100). Electrically evoked forces including the ratio of low- to high-frequency doublets were similar between trials at exercise cessation but subsequently increased more ( P < 0.05) after the 3 min TT compared with either the 10 or 40 min TT when measured at 1 or 2 min of recovery. MVC force was not different between trials. The results demonstrate that recovery of peripheral fatigue including low-frequency fatigue depends on the duration and intensity of the preceding self-paced exercise. These differences in recovery probably indicate differences in the mechanisms of fatigue for these different TTs. Because recovery is faster after a 3 min TT than a 40 min TT, delayed assessment of fatigue will detect a difference in peripheral fatigue between trials that was not present at exercise cessation., (Copyright © 2020 Froyd, Beltrami, Millet, MacIntosh and Noakes.)

It has been proposed that exercise-induced systemic oxidative stress increases circulating hematopoietic stem and progenitor cell (HPC) number in active participants, while HPC clonogenicity is reduced post-exercise. However, HPCs could be protected against exercise-induced reactive oxygen species in a trained state. Therefore, we characterized the acute exercise-induced HPC profile of well-trained participants including cell number, clonogenicity, and clearance. Twenty-one healthy, well-trained participants-12 runners, 9 cyclists; age 30.0 (4.3) years-performed a strenuous acute exercise session consisting of 4 bouts of 4-min high-intensity with 3-min low-intensity in-between, which is known to elicit oxidative stress. Average power/speed of intense phases was 85% of the peak achieved in a previous incremental test. Before and 10 min after exercise, CD34+/45dim cell number and clonogenicity, total oxidative (TOC), and antioxidative (TAC) capacities, as well as CD31 expression on detected HPCs were investigated. TOC significantly decreased from 0.093 (0.059) nmol/l to 0.083 (0.052) nmol/l post-exercise ( p = 0.044). Although HPC proportions significantly declined below baseline (from 0.103 (0.037)% to 0.079 (0.028)% of mononuclear cells, p < 0.001), HPC concentrations increased post-exercise [2.10 (0.75) cells/μl to 2.46 (0.98) cells/μl, p = 0.002] without interaction between exercise modalities, while HPC clonogenicity was unaffected. Relating HPC concentrations and clonogenicity to exercise session specific (anti-) oxidative parameters, no association was found. CD31 median fluorescent intensity expression on detected HPCs was diminished post-exercise [from 1,675.9 (661.0) to 1,527.1 (558.9), p = 0.023] and positively correlated with TOC ( r rm = 0.60, p = 0.005). These results suggest that acute exercise-reduced oxidative stress influences HPC clearance but not mobilization in well-trained participants. Furthermore, a well-trained state protected HPCs' clonogenicity from post-exercise decline., (Copyright © 2020 Kröpfl, Beltrami, Gruber, Stelzer and Spengler.)

Background: We investigated the inter-day repeatability of newly proposed indexes of cardiovascular health based on the absolute (PWVABS) or relative (PWVRATIO) difference in pulse wave velocity (PWV) between the carotid-femoral (PWVCF) and carotid-radial (PWVCR) segments compared with PWVCF alone and with systolic blood pressure (BPSYST) over multiple days., Methods: All variables were measured in triplicates in a group of 16 young, healthy individuals (8 men/8 women, body mass 66 ± 14 kg, height 1.7 ± 0.1 m, age 27 ± 3 years old, all mean ± SD) on 6 different occasions, always at the same time of the day (± 1 hour) and with at least 48 hours between assessments., Results: Values did not differ significantly over the 6 different visits for any of the parameters (all Ps > 0.08). Intraclass coefficients (ICCs) ranged from 0.52 (PWVRATIO) to 0.8 (PWVCF). The ICC 95% confidence interval of PWVRATIO (0.30-0.77) and PWVABS (0.33-0.78) did not overlap with that of PWVCF (0.79-0.95), indicating lower repeatability. The coefficient of variation (CV) of PWVABS was over 5-fold larger than the next largest one (46.7 vs. 8.1% for PWVABS and PWVRATIO, respectively), whereas PWVCF and BPSYST showed the lowest CVs (4.6 and 4.0%, respectively)., Conclusion: Between PWVABS and PWVRATIO, the relative method showed better repeatability and might be more sensitive to longitudinal changes in patients. Nonetheless, indexes of arterial stiffness-based PWV gradients between different segments show lower inter-day repeatability compared with PWVCF or BPSYST, suggesting that the latter are still preferable in clinical practice.

Introduction: Recently a novel, time-saving respiratory muscle sprint-interval training (RMSIT) was developed. To test the extent to which RMSIT improves respiratory muscle performance compared with a conventional respiratory muscle endurance training (RMET), a novel incremental respiratory muscle test (IncRMT), loading inspiratory and expiratory muscles, was designed to assess performance changes associated with respiratory muscle training (RMT)., Methods: Healthy, moderately trained males and females (age: 26 ± 5 yr, V˙O2peak: 47 ± 12 mL·min·kg) were randomized and balanced to three groups (RMSIT 5m/5f; RMET 6m/6f; PLAT 5m/6f). Lung function, respiratory muscle strength, and IncRMT performance were tested before and after 1 month of RMT. During the IncRMT, muscle activity and muscle deoxygenation were assessed via surface EMG and near-infrared spectroscopy of sternocleidomastoid (STERNO), intercostal (INTER), and abdominal (ABDO) muscles., Results: Two-way ANOVA revealed a main effect of training for increased maximal voluntary ventilation (P = 0.001) and maximal inspiratory pressure (P = 0.017). Both RMT groups increased work of breathing during training sessions to the same extent (RMSIT: +17.4 ± 8.9 kJ; RMET: +26.2 ± 16.1 kJ; P = 0.143) with a larger increase in average mouth pressure in RMSIT (RMSIT: +20.0 ± 15.0 cm H2O; RMET: +3.3 ± 1.5 cm H2O; P = 0.001). After training, IncRMT duration increased in both RMT groups compared with PLAT (RMSIT: +5.6 ± 2.1 min, P = 0.0006 vs PLAT; RMET: +3.8 ± 4.2 min, P = 0.020 vs PLAT). At similar work, only INTER activity during inspiration increased after RMET. Higher performance after RMSIT was associated with higher activity in STERNO and ABDO, but after RMET, STERNO, INTER, and ABDO showed higher activity., Conclusion: One month of RMSIT and RMET shows similar improvements in respiratory muscle performance despite different duration of training sessions. Also, muscular adaptations might differ.

We asked whether the level of peripheral fatigue would differ when three consecutive exercise trials were completed to task failure, and whether there would be delayed recovery in maximal voluntary contraction (MVC) force, neuromuscular activation and peripheral fatigue following task failure. Ten trained sport students performed three consecutive knee extension isometric trials (T1, T2, T3) to task failure without breaks between trials. T1 and T2 consisted of repeated 5-s contractions followed by 5-s rests. In T1, contractions were performed at a target force at 60% pre-exercise MVC. In T2, all contractions were MVCs, and task failure occurred at 50% MVC. T3 was a sustained MVC performed until force fell below 15% MVC. Evoked force responses to supramaximal electrical femoral nerve stimulation were recorded to assess peripheral fatigue. Electromyography signals were normalized to an M-wave amplitude to assess neuromuscular activation. Lower levels of evoked peak forces were observed at T3 compared with T2 and T1. Within 5 s of task failure in T3, MVC force and neuromuscular activation recovered substantially without any recovery in evoked peak force. Neuromuscular activation 5⁻10 s after T3 was unchanged from pre-exercise values, however, evoked peak forces were substantially reduced. These results challenge the existence of a critical peripheral fatigue threshold that reduces neuromuscular activation. Since neuromuscular activation changed independently of any change in evoked peak force, immediate recovery in force production after exercise is due to increased central recruitment and not to peripheral mechanisms.

It has been proposed that group III and IV muscle afferents provide inhibitory feedback from locomotor muscles to the central nervous system, setting an absolute threshold for the development of peripheral fatigue during exercise. The aim of this study was to test the validity of this theory. Thus, we asked whether the level of developed peripheral fatigue would differ when two consecutive exercise trials were completed to task failure. Ten trained sport students performed two exercise trials to task failure on an isometric dynamometer, allowing peripheral fatigue to be assessed 2 s after maximal voluntary contraction (MVC) post task failure. The trials, separated by 8 min, consisted of repeated sets of 10 × 5-s isometric knee extension followed by 5-s rest between contractions. In each set, the first nine contractions were performed at a target force at 60% of the pre-exercise MVC, while the 10th contraction was a MVC. MVC and evoked force responses to supramaximal electrical femoral nerve stimulation on relaxed muscles were assessed during the trials and at task failure. Stimulations at task failure consisted of single stimulus (SS), paired stimuli at 10 Hz (PS10), paired stimuli at 100 Hz (PS100), and 50 stimuli at 100 Hz (tetanus). Time to task failure for the first trial (12.84 ± 5.60 min) was longer ( P < 0.001) than for the second (5.74 ± 1.77 min). MVC force was significantly lower at task failure for both trials compared with the pre-exercise values (both P < 0.001), but there were no differences in MVC at task failure in the first and second trials ( P = 1.00). However, evoked peak force for SS, PS100, and tetanus were all reduced more at task failure in the second compared to the first trial ( P = 0.014 for SS, P < 0.001 for PS100 and tetanus). These results demonstrate that subjects do not terminate exercise at task failure because they have reached a critical threshold in peripheral fatigue. The present data therefore question the existence of a critical peripheral fatigue threshold during intermittent isometric exercise to task failure with the knee extensors.

Purpose: The aim of this study was to determine if exercise time trials (TT) of different durations would cause different levels of peripheral and central fatigue during exercise., Methods: Twelve trained subjects (11 men, one woman) performed TT lasting 3, 10, and 40 min with repetitive self-paced concentric right knee extension at 60°·s on an isokinetic dynamometer. Neuromuscular function was assessed before, during, and immediately after the TT using voluntary and electrically evoked forces., Results: Maximal voluntary contraction force, evoked peak force for single stimulus, and rating of perceived exertion reached similar levels at termination of all TT. Evoked peak force for paired stimuli of 100 Hz decreased more for the 40-min TT compared with the 3-min TT (-42% ± 15% vs -37% ± 13%, P < 0.05), and central fatigue was significant for the 40-min TT and 10-min TT but not for the 3-min TT. Single stimulus and paired stimuli of 100 Hz decreased, whereas voluntary electromyography normalized to M-wave for self-paced contractions increased during the end-spurt in all TT., Conclusions: These data demonstrate that the extent of peripheral and central fatigue that contribute to reductions in force of single-limb dynamic contractions depend on the duration and intensity of self-paced exercise. There was no evidence for a critical threshold in peripheral fatigue that was common to all TT.

Yoga alters spontaneous respiratory regulation and reduces hypoxic and hypercapnic ventilatory responses. Since a lower ventilatory response is associated with an improved endurance capacity during whole-body exercise, we tested whether yogic subjects (YOGA) show an increased endurance capacity compared to matched non-yogic individuals (CON) with similar physical activity levels. Resting ventilation, the ventilatory response to hypercapnia, passive leg movement and exercise, as well as endurance performance were assessed. YOGA (n = 9), compared to CONTROL (n = 6), had a higher tidal volume at rest (0.7±0.2 vs. 0.5±0.1 l, p = 0.034) and a reduced ventilatory response to hypercapnia (33±15 vs. 47±15 l·min(-1), p = 0.048). A YOGA subgroup (n = 6) with maximal performance similar to CONTROL showed a blunted ventilatory response to passive cycling (11±2 vs. 14±2 l·min(-1), p = 0.039) and a tendency towards lower exercise ventilation (33±2 vs. 36±3 l·min(-1), p = 0.094) while cycling endurance (YOGA: 17.3±3.3; CON: 19.6±8.5 min, p = 0.276) did not differ. Thus, yoga practice was not associated with improved exercise capacity nor with significant changes in exercise ventilation despite a significantly different respiratory regulation at rest and in response to hypercapnia and passive leg movement.

Poor sleep quality is a consistently reported by patients in the ICU. In such a potentially hostile environment, sleep is extremely fragmented and sleep architecture is unconventional, with a predominance of superficial sleep stages and a limited amount of time spent in the restorative stages. Among the causes of sleep disruption in the ICU are factors intrinsic to the patients and the acute nature of their condition, as well as factors related to the ICU environment and the treatments administered, such as mechanical ventilation and drug therapy. Although the consequences of poor sleep quality for the recovery of ICU patients remain unknown, it seems to influence the immune, metabolic, cardiovascular, respiratory, and neurological systems. There is evidence that multifaceted interventions focused on minimizing nocturnal sleep disruptions improve sleep quality in ICU patients. In this article, we review the literature regarding normal sleep and sleep in the ICU. We also analyze sleep assessment methods; the causes of poor sleep quality and its potential implications for the recovery process of critically ill patients; and strategies for sleep promotion.

Objective: Bedside lung ultrasound (LUS) is a noninvasive, readily available imaging modality that can complement clinical evaluation. The Bedside Lung Ultrasound in Emergency (BLUE) protocol has demonstrated a high diagnostic accuracy in patients with acute respiratory failure (ARF). Recently, bedside LUS has been added to the medical training program of our ICU. The aim of this study was to investigate the accuracy of LUS based on the BLUE protocol, when performed by physicians who are not ultrasound experts, to guide the diagnosis of ARF., Methods: Over a one-year period, all spontaneously breathing adult patients consecutively admitted to the ICU for ARF were prospectively included. After training, 4 non-ultrasound experts performed LUS within 20 minutes of patient admission. They were blinded to patient medical history. LUS diagnosis was compared with the final clinical diagnosis made by the ICU team before patients were discharged from the ICU (gold standard)., Results: Thirty-seven patients were included in the analysis (mean age, 73.2 ± 14.7 years; APACHE II, 19.2 ± 7.3). LUS diagnosis had a good agreement with the final diagnosis in 84% of patients (overall kappa, 0.81). The most common etiologies for ARF were pneumonia (n = 17) and hemodynamic lung edema (n = 15). The sensitivity and specificity of LUS as measured against the final diagnosis were, respectively, 88% and 90% for pneumonia and 86% and 87% for hemodynamic lung edema., Conclusions: LUS based on the BLUE protocol was reproducible by physicians who are not ultrasound experts and accurate for the diagnosis of pneumonia and hemodynamic lung edema.

High-altitude natives are challenged by hypoxia, and a potential compensatory mechanism could be reduced blood oxygen-binding affinity (P50), as seen in several high-altitude mammalian species. In 21 Qinghai Tibetan and nine Han Chinese men, all resident at 4200 m, standard P50 was calculated from measurements of arterial PO2 and forehead oximeter oxygen saturation, which was validated in a separate examination of 13 healthy subjects residing at sea level. In both Tibetans and Han Chinese, standard P50 was 24.5 ± 1.4 and 24.5 ± 2.0 mmHg, respectively, and was lower than in the sea-level subjects (26.2 ± 0.6 mmHg, P < 0.01). There was no relationship between P50 and haemoglobin concentration (the latter ranging from 15.2 to 22.9 g dl(-1) in Tibetans). During peak exercise, P50 was not associated with alveolar-arterial PO2 difference or peak O2 uptake per kilogram. There appears to be no apparent benefit of a lower P50 in this adult high-altitude Tibetan population., (© 2014 The Authors. Experimental Physiology © 2014 The Physiological Society.)

The aim of this study was to investigate the effect of potentiation on stimulation-induced muscle function during and after an intense bout of self-paced dynamic exercise. Ten active subjects performed a time trial involving repetitive concentric extension-flexion of the right knee using a Biodex dynamometer. Electrical stimulation before and after a 5 s maximal isometric voluntary contraction was performed before the start of the time trial and immediately (< 5 s) after each 20% of the time trial as well as 1, 2, 4 and 8 min after time trial termination. Potentiation was observed before the time trial and as early as 1-2 min after the time trial, but no potentiation was detected during or immediately after the time trial for neither single or paired stimuli. At termination of the time trial, "potentiated" peak torque was significantly more reduced than "unpotentiated" peak torque for single stimulus (-65 ± 10% and -42 ± 18%, respectively) and paired stimuli at 100 Hz (-51 ± 10% and -33 ± 15%, respectively). Faster recovery for "potentiated" compared to "unpotentiated" peak torque indicate that potentiate peak torque measurements or delay the post-exercise measurements more than a few seconds, will underestimate peripheral fatigue. In conclusion, the potentiation after maximal contraction disappears during intense exercise. Whether the muscle is already potentiated during intense contraction or fatiguing mechanisms inhibits potentiation remains to be clarified.

Objectives: It is believed that a plateau in oxygen consumption (VO2) at the end of an incremental exercise test identifies the upper limits of cardiovascular capacity. We investigated how different criteria influence the frequency with which the "plateau phenomenon" is detected and the prevalence at which "false" plateau phenomena occurs during sub-maximal exercise., Design: Cross-sectional., Methods: Six different criteria with 3 different sampling intervals each were used to identify the "plateau phenomenon" from a single data set comprising 63 incremental exercise tests along with secondary criteria based on target heart rate (HR) and respiratory exchange ratio (RER). A single criterion from the original 18 (HALF) was also used to detect the incidence of any plateau phenomena during each test., Results: The plateau phenomenon was detected in 16-82% of the tests depending on the criteria used, mostly as a result of the different sampling intervals. HALF identified 103 "plateau phenomena" but 73 (70.9%) of these occurred during sub-maximal exercise and so were "false". "False" plateaus were verified by at least one secondary criterion in 27% of cases. Participants reached the HR and RER targets after 83.6 ± 11.7% and 81.9 ± 18.1% of total test duration, respectively., Conclusions: The wide range in the percentage of plateau phenomena detected by different criteria plus the high rate (71%) of "false" plateau during sub-maximal exercise could indicate that this phenomenon is a calculation artifact rather than an indicator of true physiological events. Secondary criteria can be reached early in exercise and often identify "false" plateau phenomena as "true"., (Copyright © 2013 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.)

Lifestyle changes have an impact on lipid metabolism. The overload of circulating lipids may lead to endothelial dysfunction, oxidative stress and exaggerated inflammatory response, which may be further aggravated in the presence of overweight. This study aims to describe the postprandial metabolism and inflammatory response in overweight and normal-weight adolescents. Sixty-two adolescents aged 11-18 years were divided into two groups: overweight (OW; n=38) and normal weight (NW; n=24). Total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), triglycerides (TG), glucose, insulin, high-sensitivity C-reactive protein (hs-CRP), fibrinogen and leukocytes were collected for fasting and 4 and 6 h after a oral fat tolerance test (OFTT) consisting of a high-fat meal with 1.000 Kcal, 27.4% carbohydrates, 14.7% protein and 57.8% lipids (30.4% saturated, 32.7% monounsaturated, 26.5% polyunsaturated fatty acids and 288 mg TC). Data were analyzed with repeated measures ANOVA, multiple linear regression, and Pearson, Spearman and partial correlations. OW adolescents showed significantly higher fasting values of TC (P=0.036), LDL-C (P=0.010), fibrinogen (P=0.036) and hs-CRP (P=0.004). All variables, except for glucose, increased in response to OFTT, but there were no interactions between group and time. body mass index z-score was positively correlated to LDL-C, TG, fibrinogen and hs-CRP, and inversely correlated to HDL-C. In conclusion, adolescents with OW showed higher TC, LDL-C and inflammatory markers levels than NW adolescents. These findings have clinical implications for prevention of chronic diseases, as we spend most of our days in a postprandial state.

Purpose: We investigated the accuracy of the Moxus Modular Metabolic System (MOXUS) against the Douglas Bag Method (DBM) during high-intensity exercise, and whether the two methods agreed when detecting small changes in [Formula: see text] between two consecutive workloads ([Formula: see text])., Methods: Twelve trained male runners performed two maximal incremental running tests while gas exchange was analyzed simultaneously by the two systems using a serial setup for four consecutive intervals of 30 s on each test. Comparisons between methods were performed for [Formula: see text], [Formula: see text], fractions of expired O2 (FeO2) and CO2 (FeCO2) and [Formula: see text]., Results: The MOXUS produced significant higher (mean ± SD, n = 54) readings for [Formula: see text] (80 ± 200 mL min(-1), p = 0.005) and [Formula: see text] (2.9 ± 4.2 L min(-1), p < 0.0001), but not FeO2 (-0.01 ± 0.09). Log-transformed 95 % limits of agreement for readings between methods were 94-110 % for [Formula: see text], 97-108 % for [Formula: see text] and 99-101 % for FeO2. [Formula: see text] for two consecutive measurements was not different between systems (120 ± 110 vs. 90 ± 190 mL min(-1) for MOXUS and DBM, respectively, p = 0.26), but agreement between methods was very low (r = 0.25, p = 0.12)., Discussion: Although it was tested during high-intensity exercise and short sampling intervals, the MOXUS performed within the acceptable range of accuracy reported for automated analyzers. Most of the differences between equipments were due to differences in [Formula: see text]. Detecting small changes in [Formula: see text] during an incremental test with small changes in workload, however, might be beyond the equipment's accuracy.

The aim of this study was to measure the extent to which potentiation changes in response to an isometric maximal voluntary contraction. Eleven physically active subjects participated in two separate studies. Single stimulus of electrical stimulation of the femoral nerve was used to measure torque at rest in unpotentiated quadriceps muscles (study 1 and 2), and potentiated quadriceps muscles torque in a 10 min period after a 5 s isometric maximal voluntary contraction of the quadriceps muscles (study 1). Additionally, potentiated quadriceps muscles torque was measured every min after a further 10 maximal voluntary contractions repeated every min (study 2). Electrical stimulation repeated several times without previous maximal voluntary contraction showed similar peak twitch torque. Peak twitch torque 4 s after a 5 s maximal voluntary contraction increased by 45±13% (study 1) and by 56±10% (study 2), the rate of torque development by 53±13% and 82±29%, and the rate of relaxation by 50±17% and 59±22%, respectively, but potentiation was lost already two min after a 5 s maximal voluntary contraction. There was a tendency for peak twitch torque to increase for the first five repeated maximal voluntary contractions, suggesting increased potentiation with additional maximal voluntary contractions. Correlations for peak twitch torque vs the rate of torque development and for the rate of relaxation were r(2)= 0.94 and r(2)=0.97. The correlation between peak twitch torque, the rate of torque development and the rate of relaxation suggests that potentiation is due to instantaneous changes in skeletal muscle contractility and relaxation.

The purpose of this study was to examine the performance of the Moxus Modular Metabolic System from AEI Technologies, Inc. using the Douglas-bag method as reference. To achieve this, eight moderately trained subjects cycled for 5 min at constant powers from 50 to 300 W in increments of 50 W. The O₂ uptake was measured simultaneously by both systems during the last minute of each stage. The O₂ uptake reported by the Moxus system was 83 ± 78 mL·min⁻¹ higher (mean ± SD; ≈3%, +62 µmol·s⁻¹, P < 0.001) than that reported by the Douglas-bag method; the bias varied by ≈2% between the subjects. The higher O₂ uptake of the Moxus system was a consequence of 1.4% ± 3.0% higher reported ventilation and 2% ± 3% higher reported O₂ extraction per volume of air breathed. The respiratory exchange ratio (R value) reported by the Moxus system rose proportionally to that of the Douglas-bag method and was 1% ± 2% higher for the range examined (0.75-1.10). Repeated tests of the maximal O₂ uptake showed a variability (coefficient of variation) of 2.5%. The study concluded that measurements by the Moxus system showed some bias and residual variation and, in addition, some systematic differences between the subjects in the O₂ uptake. The R value was reported quite accurately with moderate random error. Although there were some computer software and hardware instability problems that need to be solved, the Moxus system worked quite well and provided data more reliable than those of most commercial instruments.

The evaluation of critically ill patients using lung ultrasound, even if performed by nonspecialists, has recently garnered greater interest. Because lung ultrasound is based on the fact that every acute illness reduces lung aeration, it can provide information that complements the physical examination and clinical impression, the main advantage being that it is a bedside tool. The objective of this review was to evaluate the clinical applications of lung ultrasound by searching the PubMed and the Brazilian Virtual Library of Health databases. We used the following search terms (in Portuguese and English): ultrasound; lung; and critical care. In addition to the most relevant articles, we also reviewed specialized textbooks. The data show that lung ultrasound is useful in the differential diagnosis of pulmonary infiltrates, having good accuracy in identifying consolidations and interstitial syndrome. In addition, lung ultrasound has been widely used in the evaluation and treatment of pleural effusions, as well as in the identification of pneumothorax. This technique can also be useful in the immediate evaluation of patients with dyspnea or acute respiratory failure. Other described applications include monitoring treatment response and increasing the safety of invasive procedures. Although specific criteria regarding training and certification are still lacking, lung ultrasound is a fast, inexpensive, and widely available tool. This technique should progressively come to be more widely incorporated into the care of critically ill patients.

Background: This study used a novel protocol to test the hypothesis that a plateau in oxygen consumption (VO(2 max)) during incremental exercise testing to exhaustion represents the maximal capacity of the cardiovascular system to transport oxygen., Methods: Twenty-six subjects were randomly divided into two groups matched by their initial VO(2 max). On separate days, the reverse group performed (i) an incremental uphill running test on a treadmill (INC(1)) plus verification test (VER) at a constant workload 1 km h(-1) higher than the last completed stage in INC(1); (ii) a decremental test (DEC) in which speed started as same as the VER but was reduced progressively and (iii) a final incremental test (INC(F)). The control group performed only INC on the same days that the reverse group was tested., Results: VO(2 max) remained within 0.6 ml kg(-1) min(-1) across the three trials for the control group (p=0.93) but was 4.4% higher during DEC compared with INC(1) (63.9 ± 3.8 vs 61.2 ± 4.8 ml kg(-1) min(-1), respectively, p=0.004) in the reverse group, even though speed at VO(2 max) was lower (14.3 ± 1.1 vs 16.2 ± 0.7 km h(-1) for DEC and INC(1), respectively, p=0.0001). VO(2 max) remained significantly higher during INC(F) (63.6 ± 3.68 ml kg(-1) min(-1), p=0.01), despite an unchanged exercise time between INC(1) and INC(F)., Conclusion: These findings go against the concept that a plateau in oxygen consumption measured during the classically described INC and VER represents a systemic limitation to oxygen use. The reasons for a higher VO(2) during INC(F) following the DEC test are unclear.

Objective: to determine the level of awareness regarding nonsteroidal anti-inflammatory drugs (NSAIDs) and the prevalence and reasons for their consumption among athletes competing at the 2008 Brazil Ironman Triathlon (3.8 km swim, 180 km cycle and 42.2 km run)., Design: survey study., Setting: 2008 Brazil Ironman Triathlon, Florianópolis, Brazil, May 2008., Participants: 327 Of the 1250 athletes competing at the 2008 Brazil Ironman Triathlon were enrolled in the study., Main Outcome Measures: athletes answered a questionnaire about NSAID effects, side effects and consumption at the bike checkout or awards lunch., Results: 196 (59.9%) Athletes reported using NSAIDs in the previous 3 months; of these, 25.5% (n=50), 17.9% (n=35) and 47.4% (n=93) consumed NSAIDs the day before, immediately before and during the race, respectively. Among NSAID users, 48.5% (n=95) consumed them without medical prescription. The main reason given for NSAID consumption in the previous 3 months was the treatment of injuries, while the main reason given for consuming NSAIDs during the race was pain prevention. Despite anti-inflammatory and analgesic effects, most athletes were unaware of the effects of NSAIDs, and the only adverse effects known by most athletes were the gastrointestinal complications., Conclusions: this study found a high prevalence of NSAID consumption, limited awareness of the effects and side effects of them and a high rate of nonprescribed use. It is suggested that long-distance triathlon events include in their programmes educational devices such as talks or folders about NSAID use, effects and side effects.

Objectives: The purpose of this review is to describe the evolution of hydration research and advice on drinking during exercise from published scientific papers, books and non-scientific material (advertisements and magazine contents) and detail how erroneous advice is likely propagated throughout the global sports medicine community., Design: Hydration advice from sports-linked entities, the scientific community, exercise physiology textbooks and non-scientific sources was analysed historically and compared with the most recent scientific evidence., Conclusions: Drinking policies during exercise have changed substantially throughout history. Since the mid-1990s, however, there has been an increase in the promotion of overdrinking by athletes. While the scientific community is slowly moving away from "blanket" hydration advice in which one form of advice fits all and towards more modest, individualised, hydration guidelines in which thirst is recognised as the best physiological indicator of each subject's fluid needs during exercise, marketing departments of the global sports drink industry continue to promote overdrinking.