ECSS Paris 2023: CP-PN07
INTRODUCTION: Exercise-induced muscle damage (EIMD) can result from unaccustomed or high-intensity eccentric exercise and is typically evaluated using objective and subjective markers of recovery. Cold- and hot water immersion (CWI and HWI, respectively) have emerged as potential post-exercise recovery interventions to accelerate recovery between training sessions or competitive events, but there is still a lack of evidence, especially in the female population. Therefore, this study aimed to evaluate the acute physiological changes and assess the effectiveness of repeated CWI and HWI in enhancing recovery in women compared to a passive control group (CON). METHODS: 30 healthy women (23.4 ±2.9 years), randomly assigned to CWI, HWI or CON groups, completed a standardised EIMD protocol. Immediately and 120min after the EIMD, participants underwent a 10min recovery intervention (CWI, HWI, or CON). To assess acute physiological responses, muscle oxygen saturation (SmO2), core and skin temperature were recorded at baseline, after muscle damage, directly after the recovery intervention (postInt) and during a 30min follow-up period. Recovery was evaluated by assessing maximal voluntary isometric contraction of the knee extensors, muscle swelling, delayed onset of muscle soreness, and creatine kinase at baseline, 24, 48 and 72h following EIMD. RESULTS: SmO2 was significantly lower in CWI than HWI (20min: 67.8 ± 2.7% vs. 74.7 ± 3.2%, p = .006; 30min: 64.4 ± 6.4% vs. 74.4 ± 3.9%, p = .001) and CWI compared to CON (20min: 73.5 ± 6.6%, p = .026; 30min: 73.0 ± 6.1%, p = .006). Core temperature was significantly higher in HWI compared to CWI at postInt and 30min (both p < .01) and compared to CON at postInt and throughout 30min follow-up (all p < .05), while there was no difference (p > .05) between CWI and CON. Skin temperature was significantly reduced in CWI compared to HWI (all p < .001) and compared to CON (all p< .05) between postInt and 30min follow-up. No significant differences were observed between CWI and HWI in objective and subjective markers of recovery throughout 72h follow-up. CONCLUSION: Despite acute physiological changes, neither CWI nor HWI improved subjective and objective recovery characteristics during a 72h follow-up period compared to the CON group.
Read CV Vanessa WellauerECSS Paris 2023: CP-PN07
INTRODUCTION: Compared to tap water immersion, CO2-water immersion is expected to increase oxygen supply through vasodilation, decrease pain, enhance immunity, and increase parasympathetic nerve activity (1,2). Therefore, CO2-water immersion has been used in our support centers to promote recovery in athletes. However, the effects of CO2-water immersion on recovery after training or consecutive games have not been reported. The purpose of the present study was to clarify the effects of CO2-water immersion on core body temperature, sleep condition, and fatigue in college athletes after training. METHODS: In a crossover design, ten male college baseball players completed three trials: CO2-water immersion (CO2), tap water immersion at 40 °C (HOT), and seated at room temperature (25 °C) (CON) for 15 min after regular training. Participants wore Actiwatch sleep monitors on their wrists on the night of the experiment to evaluate their sleep state. Core temperature (Tcore) was measured throughout the night until the morning of the next day. RESULTS: The maximum Tcore showed moderately higher values (d = 0.534, p = 0.541) in the CO2 trail (38.12 ± 0.50 °C) than in the HOT trail (37.86 ± 0.48 °C). The CO2 and HOT trials exhibited mostly higher values (d = 1.852, p = 0.004 and 1.238, p = 0.032, respectively) than the CON trail (37.38 ± 0.27 °C). Minimal variations were observed in sleep duration (CO2, 5.76 ± 1.1 h; HOT, 5.42 ± 1.1 h; and CON, 5.93 ± 1.0 h), and the effect size was small (d < 0.5). Sleep efficiency and quality of sleep were moderately higher in the CO2 trail than in the HOT trail (d = 0.577, p = 0.574 and 0.512, p = 0.669, respectively). The difference between the Tcore at sleep onset and the maximal Tcore was slightly greater (d = 0.364, p = 0.497) in the CO2 trail (-0.94 ± 0.54 °C) than in the HOT trail (-0.78 ± 0.32 °C). CONCLUSION: CO2-water immersion increased core body temperatures more significantly than hot tap water immersion at 40 °C. These increased temperatures resulted in positive effects on sleep efficiency and sleep quality, which may be due in part to the significant decrease in core body temperature at the time of sleep onset. References (1) Ihsan M, Watson G, Abbiss CR. What are the physiological mechanisms for post-exercise cold water immersion in the recovery from prolonged endurance and intermittent exercise?. Sports Med,46(8):1095–109,2016. (2) Versey NG, Halson SL, Dawson BT. Water immersion recovery for athletes: effect on exercise performance and practical recommendations. Sports Med,43(11):1101–30,2013.
Read CV RISA IWATAECSS Paris 2023: CP-PN07
INTRODUCTION: Bouts of eccentric muscle-damaging exercise or heat exposure have the potential to reduce physiological and cellular stress during future exertional-heat exposure. Given potential cross adaptations, this study investigated the effect of muscle-damaging exercise in the heat on reducing physiological and cellular stress during future exertional-heat exposure. METHODS: Ten healthy, physically active males (mean ± SD; age, 23 ± 3 years; body mass, 78.7 ± 11.5 kg; height, 176.9 ± 4.7 cm) completed this study. In a randomised, counterbalanced order, participants were assigned into two groups; a) downhill running (DHR) in the heat (ambient temperature [Tamb], 35°C; relative humidity [RH], 40%), and b) DHR in thermoneutral (Tamb, 20°C; RH, 20%) to evoke muscle damage. Seven days following DHR, participants performed a 45-minute flat run in the heat (FlatHEAT [Tamb, 35°C; RH, 40%]). During exercise trials, heart rate (HR) and rectal temperature (Trec) were recorded at baseline and every 5-minutes. Peripheral blood mononuclear cells were isolated and homogenised to assess heat shock protein 72 (Hsp72) concentration between conditions at baseline, immediately post-DHR, and immediately pre- and post-FlatHEAT. RESULTS: Mean Trec during FlatHEAT between hot (38.23 ± 0.38 oC) and thermoneutral (38.26 ± 0.38 oC) were not significantly different (p = 0.68), with no mean HR differences during FlatHEAT between hot (172 ± 15 beats.min-1) and thermoneutral (174 ± 8 beats.min-1; p = 0.58). Hsp72 concentration change from baseline to immediately pre-FlatHEAT was significantly lower in hot (-51.4%) compared to thermoneutral (+24.2%; p = 0.025), with Hsp72 change from baseline to immediately post-FlatHEAT also lower in hot (-52.6%) compared to thermoneutral (+26.3%; p = 0.047). CONCLUSION: A singular bout of muscle-damaging exercise in the heat reduces cellular stress levels prior to and immediately following future exertional-heat exposure. Individuals regularly exposed to exertional-heat stress (e.g., athletes, military personnel, and firefighters) would likely benefit from implementing this preconditioning modality during heat preparation, particularly when the window to perform more robust heat adaptation methods is insufficient (e.g., heat acclimation/acclimatisation).
Read CV Ryan DunnECSS Paris 2023: CP-PN07