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Exposure to either natural or simulated hypoxia induces hematological adaptations that may affect the parameters of the Athlete Biological Passport (ABP). The aim of the present study was to examine the effect of a novel, mixed hypoxic dose protocol on the likelihood of producing an atypical ABP finding. Ten well-trained middle-distance runners participated in a "live high, train low and high" (LHTLH) altitude training camp for 14 days. The participants spent ˜6 hr.d-1 at 3000-5400 m during waking hours and ˜10 h.d-1 overnight at 2400-3000 m simulated altitude. Venous blood samples were collected before (B0), and after 1 (D1), 4 (D4), 7 (D7), and 14 (D14) days of hypoxic exposure, and again 14 days post exposure (P14). Samples were analyzed for key parameters of the ABP including reticulocyte percentage (Ret%), hemoglobin concentration ([Hb]), and the OFF-score. The ABP adaptive model was administered at a specificity of 99% to test for atypical findings. We found significant changes in [Hb] and Ret% during the hypoxic intervention. Consequently, this led to ABP threshold deviations at 99% specificity in three participants. Only one of these was flagged as an "atypical passport finding" (ATPF) due to deviation of the OFF-score. When this sample was evaluated by ABP experts it was considered "normal". In conclusion, it is highly unlikely that the present hypoxic exposure protocol would have led to a citation for a doping violation according to WADA guidelines.

Whether cyclooxygenase (COX)/prostaglandin E2 (PGE2) thermoregulatory pathways, observed in rodents, present in humans? Participants (n = 9) were exposed to three environments; cold (20 °C), thermoneutral (30 °C) and hot (40 °C) for 120 min. Core (Tc)/skin temperature and thermal perception were recorded every 15 min, with COX/PGE2 concentrations determined at baseline, 60 and 120 min. Linear mixed models identified differences between and within subjects/conditions. Random coefficient models determined relationships between Tc and COX/PGE2. Tc [mean (range)] increased in hot [+ 0.8 (0.4–1.2) °C; p

This study identified the changes in hypertrophy/atrophy and mitochondrial-related signaling in human skeletal muscle following whole-body (WB) and localized single leg (SL) heat treatment. Nine active male participants were administered either 60 min of passive WB (44–50°C, 50% humidity) or SL (water-perfused suit at 49.5 ± 1.4°C) heat treatment at least 1 week apart in a counterbalanced order. The untreated leg during SL was considered as control (CON). Core, skin, and quadriceps muscle temperature were monitored throughout the experimental trials. Muscle microbiopsy samples were obtained prior to (PRE), and 30 min and 3 h post (POST) following heat treatment. Muscle temperature increased with time (p < 0.0001) in both WB and SL, with no differences between conditions (38.8 ± 0.5°C vs. 38.1 ± 0.6°C, p = 0.065). Core temperature increased only following WB, and was significantly higher compared with SL (39.1 ± 0.3°C vs. 37.1 ± 0.1, p < 0.0001). Compared with PRE, WB up-regulated the phosphorylation status of the majority of the Akt/mTOR pathway (Akt, mTOR, S6K1, rpS6, and p-eIF4E; p ≤ 0.050), with the exception of 4EBP1 (p = 0.139). WB also increased the mRNA of HSPs 72, 90, and 25 (all p < 0.021), and increased or tended to increase the phosphorylation of FOXO1 (p = 0.066) and FOXO3a (p = 0.038). In addition, most (NRF1, NRF2, COX2, and COX4-I2; all p ≤ 0.050), but not all (CS, Cyt c, and COX4-I1; p > 0.441) mRNA content indicative of mitochondrial biogenesis were increased following WB, with no changes evident in these parameters in SL or CON (all p > 0.090). These results indicate that 1 h of WB heat treatment enhanced anabolic (Akt/mTOR), mitochondrial, and cyto-protective signaling (HSP), with a concomitant possible inhibition of FOXO transcription factors.

To determine the effect of carbohydrate mouth rinsing (CHO-MR) on physical and cognitive performance during repeated-sprints (RS) after 3 days of intermittent fasting (abstaining from food and fluid 14 h per day). In a randomized and counter-balanced manner 15 active healthy males in a fasted state performed a RS-protocol [RSP; 2 sets (SET1 and SET2) of 5×5 s maximal sprints, with each sprint interspersed with 25 s rest and 3 min of recovery between SET1 and SET2] on an instrumented non-motorized treadmill with embedded force sensors under three conditions: i) Control (CON; no-MR), ii) Placebo-MR (PLA-MR; 0% maltodextrin) and iii) CHO-MR (10% maltodextrin). Participants rinsed their mouth with either 10 mL of PLA-MR or CHO-MR solution for 5 s before each sprint. Sprint kinetics were measured for each sprint and reaction time (RTI) tasks (simple and complex) were assessed pre-, during- and post-RSP. There was no statistical main effect of CHO-MR on mean power, mean speed, and vertical stiffness during the sprints between the PLA-MR and CON condition. Additionally, no statistical main effect for CHO-MR on accuracy, movement time and reaction time during the RTI tasks was seen. CHO-MR did not affect physical (RSP) or cognitive (RTI) performance in participants who had observed 3 days of intermittent fasting (abstaining from food and fluid 14 h per day).

BackgroundThe association between bone mineral density (BMD) and serum25-hydroxyvitamin D (25(OH)D) concentration is weak, particularly in certain races (eg, BlackAfrican vs Caucasian) and in athletic populations. We aimed to examine if bioavailable vitamin D rather than serum 25(OH)D was related to markers of bone health within a racially diverse athletic population.MethodsIn 604 male athletes (Arab (n=327), Asian (n=48), Black (n=108), Caucasian (n=53) and Hispanic (n=68)), we measured total 25(OH)D, vitamin D-binding protein and BMD by DXA. Bioavailable vitamin D was calculated using the free hormone hypothesis.ResultsFrom 604 athletes, 21.5% (n=130) demonstrated severe 25(OH)D deficiency, 37.1% (n=224) deficiency, 26% (n=157) insufficiency and 15.4% (n=93) sufficiency. Serum 25(OH)D concentrations were not associated with BMD at any site. After adjusting for age and race, bioavailable vitamin D was associated with BMD (spine, neck and hip). Mean serum vitamin D binding protein concentrations were not associated with 25(OH)D concentrations (p=0.392).ConclusionRegardless of age or race, bioavailable vitamin D and not serum 25(OH)D was associated with BMD in a racially diverse athletic population. If vitamin D screening is warranted, clinicians should use appropriate assays to calculate vitamin D binding protein and bioavailable vitamin D levels concentrations than serum 25(OH)D. In turn, prophylactic vitamin D supplementation to ‘correct’ insufficient athletes should not be based on serum 25(OH)D measures.

Although the role of vitamin D in calcium and bone metabolism is well documented, there is little clarity regarding the implications of low vitamin D status for inflammation, endothelial function, and antioxidant status in adolescent athletes. A prospective cohort study was conducted, and 44 male adolescent athletes, training at a sports academy in the Middle East, were assigned to either the intervention group (VitDs), consisting of vitamin D deficient athletes [twenty-five hydroxyvitamin D (25(OH)D) 30 ng/ml ; n = 22]. Vitamin D status, inflammatory cytokines, endothelium-related variables, and antioxidant enzymes were measured twice during a nine-week training period. At the baseline, the athletes in the VitDs group had significantly lower concentrations of 25(OH)D, vascular endothelial growth factor (VEGF), and glutathione peroxidase (GPx), and higher levels of parathyroid hormone (PTH), interleukin-6 (IL-6), interleukin-1 receptor antagonist (IL-1ra), and nitrite (NO2) (p < 0.05), in comparison to the athletes in the sufficient group. After vitamin D supplementation for the VitDs group, the two cohorts differed considerably in vitamin D binding protein (VDBP) and PTH concentrations (p < 0.05). Our data suggest that the low levels of vitamin D possibly induced alterations in the investigated biochemical parameters of athletes in the VitDs group at the beginning of the monitoring period. Furthermore, while the vitamin D supplementation was effective in increasing 25(OH)D status, it may have concurrently positively influenced variables that are related to inflammation, endothelial function, and enzymatic antioxidants.

Objective: The aim of this study was to assess the effects of 3-day Islamic intermittent fasting (3d-IF) on cognitive performance and serum levels of neurotrophic factors (brain-derived neurotrophic factor [BDNF] and vascular endothelial growth factor [VEGF]) before and after repeated sprints. Methods: Twenty-one physically active male Muslims (29.8 5.9 years, exercising 4 1.5 times/week) were randomly assigned to one of 2 experimental sessions: the control or nonfasting session (CS) or the fasting session (FS). These 2 sessions occurred 7 days apart in a counterbalanced crossover design. In both conditions, the test was performed at the same time of day, approximately hour before sunset. In the FS, the test occurred on the third day of the 3d-IF and involved the participants' performance of the following: (a) two series of 5 maximal 5-second sprints and (b) 2 cognitive tasks: One Touch Stockings (OTS) and reaction time (simple and complex RTI). Results: In both conditions, the participants' reaction times during the RTI test were similar at the pre- and mid-exercise points, but postexercise, simple and complex reaction times were higher in FS compared to CS (p = 0.045, effect size [ES] = 0.21 and p = 0.006, ES = 0.41, respectively). However, OTS performance and serum levels of neurotrophic factors were not influenced by the 3d-IF. Conclusion: Simple and complex reaction times during the RTI test were negatively affected by the 3d-IF after 2 bouts of intensive repeated sprints. Scopus

Purpose:To examine the effects of 3 d of intermittent fasting (3d-IF: abstaining from eating/drinking from dawn to sunset) on physical performance and metabolic responses to repeated sprints (RSs).Methods:Twenty-one active males performed an RS test (2 sets: 5 × 5-s maximal sprints with 25 s of recovery between and 3 min of recovery between sets on an instrumented treadmill) in 2 conditions: counterbalanced fed/control session (CS) and fasting session (FS). Biomechanical and biochemical markers were assessed preexercise and postexercise.Results:Significant main effects of IF were observed for sprints: maximal speed (P = .016), mean speed (P = .015), maximal power (P = .035), mean power (P = .049), vertical stiffness (P = .032), and vertical center-of-mass displacement (P = .047). Sprint speed and vertical stiffness decreased during the 1st (P = .003 and P = .005) and 2nd sprints (P = .046 and P = .048) of set 2, respectively. Postexercise insulin decreased in CS (P = .023) but not in FS (P = .230). Free-fatty-acid levels were higher in FS than in CS at preexercise (P < .001) and at postexercise (P = .009). High-density lipoprotein cholesterol (HDL-C) was higher at postexercise in FS (1.32 ± 0.22 mmol/L) than in CS (1.26 ± 0.21 mmol/L, P = .039). The triglyceride (TG) concentration was decreased in FS (P < .05) compared with CS.Conclusions:3d-IF impaired speed and power through a decrease in vertical stiffness during the initial runs of the 2nd set of RS. The findings of the current study confirmed the benefits of 3d-IF: improved HDL-C and TG profiles while maintaining total cholesterol and low-density lipoprotein cholesterol levels. Moreover, improving muscle power might be a key factor to retain a higher vertical stiffness and to partly counteract the negative effects of intermittent fasting.

The aim of this review was to highlight the potent effects of intermittent fasting on the cognitive performance of athletes at rest and during exercise. Exercise interacts with dietary factors and has a positive effect on brain functioning. Furthermore, physical activity and exercise can favorably influence brain plasticity. Mounting evidence indicates that exercise, in combination with diet, affects the management of energy metabolism and synaptic plasticity by affecting molecular mechanisms through brain-derived neurotrophic factor, an essential neurotrophin that acts at the interface of metabolism and plasticity. The literature has also shown that certain aspects of physical performance and mental health, such as coping and decision-making strategies, can be negatively affected by daylight fasting. However, there are several types of intermittent fasting. These include caloric restriction, which is distinct from fasting and allows subjects to drink water ad libitum while consuming a very low-calorie food intake. Another type is Ramadan intermittent fasting, which is a religious practice of Islam, where healthy adult Muslims do not eat or drink during daylight hours for 1 month. Other religious practices in Islam (Sunna) also encourage Muslims to practice intermittent fasting outside the month of Ramadan. Several cross-sectional and longitudinal studies have shown that intermittent fasting has crucial effects on physical and intellectual performance by affecting various aspects of bodily physiology and biochemistry that could be important for athletic success. Moreover, recent findings revealed that immunological variables are also involved in cognitive functioning and that intermittent fasting might impact the relationship between cytokine expression in the brain and cognitive deficits, including memory deficits.

The objective of this study was to determine the effect of hyperthermic environment in combination with exercise on the plasma concentration of interleukin-1ra (IL-1ra), interleukin-6 (IL-6) and C-...