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The increase of wide-spread participation in endurance events in sports such as open water swimming, cycling, running and triathlons, has given rise to a concern about potential implications for renal function and kidney health. This study aimed to delve into the findings on exertional rhabdomyolysis (ER) and acute kidney injury (AKI) in endurance sports, emphasizing the diagnostic criteria used, physical and environmental contextual conditions in which ER and AKI are reported. Following PRISMA guidelines for systematic reviews and meta-analysis, topic related studies were searched digital sources (from 2009 to 2020). Studies with biomarkers of ER and AKI reported in endurance or ultra-endurance events were included. A total of 43 publications (sample = 813) were extracted, and 345 (43.5%) individuals were diagnosed with ER (creatinine kinase > 5000 UI/L) and 130 (16.39%) with ER + AKI (creatinine ≥ 1.88 mg/dL). Out of the total cases of ER + AKI, 96.92% were in ultra-endurance runners. There were inconsistences between studies in diagnosis criteria for ER and AKI, which represented a difficulty in the interpretation of the data. Increased levels of muscle and kidney injury immediately after endurance events were reported, but after 5.86 days these levels usually returned to baseline. There is a lack of knowledge around the potential of repeated ER and AKI predisposing to long-term chronic kidney disease. More accurate markers for subclinical and functional AKI diagnosis are needed in the analysis of kidney health after endurance events. ER and AKI are serious clinical problems with significant morbidity. Further research may be in order to help define future prevention strategies. [ABSTRACT FROM AUTHOR]

Hypoxic training methods are increasingly being used by researchers in an attempt to improve performance in normoxic ambients. Moreover, previous research suggests that resistance training in hypoxia can cause physiological and muscle adaptations. The primary aim of this study was to compare the effects of 8 weeks of high-intensity resistance circuit-based (HRC) training in hypoxia on body composition and strength performance. The secondary aim was to examine the effects of HRC on metabolic parameters. Twenty-eight male participants were randomly assigned to either hypoxia (Fraction of inspired oxygen [FIO2] = 15%; HRChyp: n = 15; age: 24.6 ± 6.8 years; height: 177.4 ± 5.9 cm; weight: 74.9 ± 11.5 kg) or normoxia [FIO2] = 20.9%; HRCnorm: n = 13; age: 23.2 ± 5.2 years; height: 173.4 ± 6.2 cm; weight: 69.4 ± 7.4 kg) groups. Training sessions consisted of two blocks of three exercises (Block 1: bench press, leg extension and front pull down; Block 2: deadlift, elbow flexion and ankle extension). Each exercise was performed at six repetition maximum. Rest periods lasted for 35-s between exercises, 3-min between sets and 5-min between blocks. Participants exercised twice weekly for 8 weeks, and body composition, strength and blood tests were performed before and after the training program. Lean body mass and bone mineral density significantly increased over time in the HRChyp (p <.005; ES = 0.14 and p <.014; ES = 0.19, respectively) but not in the HRCnorm after training. Both groups improved their strength performance over time (p <.001), but without group effect differences. These results indicate that simulated hypoxia during HRC exercise produced trivial effects on lean body mass and bone mineral density compared to normoxia. [ABSTRACT FROM AUTHOR]

Purpose: Promising benefits on fat mass and biochemical components may be reported after applying programs of cyclic hypoxia and HIIT. Aim: To investigate the effect of a month of detraining on cardiometabolic risk markers after active hypoxia exposure. Methods: Participants included 59 overweight/obese women, who started a 12‐week program of 36 sessions, and were randomly divided into four groups: (a) aerobic interval training in hypoxia (AitH; FiO2 = 17.2%; n = 13), (b) aerobic interval training in normoxia (AitN; n = 15), (c) sprint interval training in hypoxia (SitH; FiO2 = 17.2%; n = 15), and (d) sprint interval training in normoxia (SitN; n = 18). Body composition, anthropometric, and biochemical parameters were assessed at baseline (A), after 36 training sessions (B) and after 4 weeks of detraining (C). Results: Hypoxia conditions showed a significant positive effect on waist circumference (P = 0.01), WHR (P = 0.04), and percentage of trunk fat mass (P < 0.001). The percentage of trunk fat continued to decrease significantly after training cessation in both AitH and SitH groups. Conclusion: After 4 weeks of detraining with a previous 12 weeks of high‐intensity interval training under cyclic normobaric hypoxia, the percentage of fat mass located in the trunk decreases significantly and this effect was not observed in the normoxia groups. [ABSTRACT FROM AUTHOR]

Aerobic exercise is associated with changes in the blood profile of fatty acids. Caffeine is known to be a potential lipolytic agent. Hence, caffeine ingestion in addition to exercise might have an influence on fatty acids, with positive effects on health and performance. The aim of the present study, therefore, was to assess the effect of caffeine (5 mg · kg body mass-1) ingested before aerobic exercise on the total plasma fatty acid profile. In a crossover, double-blind, randomized study involving 20 untrained males ([image omitted] 43.57±6.48 ml · kg-1 · min-1), blood lactate concentration, plasma caffeine values, and plasma fatty acid profile were examined using chromatographic techniques before and after 30 min of steady-state cycle exercise at 75% [image omitted] under placebo and caffeine conditions. Ventilatory responses and substrate oxidation rates were determined during exercise and recovery. Ventilatory responses, lactate concentrations, and fat and carbohydrate oxidation rates were not affected by caffeine ingestion. Carbohydrate was the main substrate oxidized during steady-state trials under both conditions, although exercise increased blood saturated fatty acids (placebo: 28.30±5.90% vs. 31.09±4.59, P<0.05; caffeine: 28.88±4.12% vs. 29.60±4.56%). Unsaturated blood concentrations of oleic fatty acid trans (C18:1t) increased due to caffeine (placebo: 2.22±2.81% vs. 2.61±3.86%; caffeine 1.53±0.19% vs. 1.70±0.49%, P<0.05). In conclusion, the ingestion of caffeine prior to moderate-to-high aerobic exercise may not have a clear metabolic advantage under the conditions of the present study in untrained individuals, although it might influence some individual unsaturated fatty acids (C18:1t) despite low fat oxidation rates. [ABSTRACT FROM AUTHOR]