Dehydration Decreases Slow Wave Sleep After Heavy Resistance Exercise

Purpose: The purpose of this study was to examine the effects of hydration status on sleep and recovery measurement before and after high volume resistance exercise. It was hypothesized that dehydration decreases sleep and recovery measurements following exercise. Methods: Eight resistance-trained men (age, 21±2 years; weight, 82.0±12.6 kg; height, 177.3±6.9 cm) performed a series of bilateral leg press and knee extensions (RE, 5 sets of 10 repetitions at 80% of 1 repetition maximum). Participants completed one trial in a euhydrated state (EUH; urine specific gravity (USG) < 1.020) and the other in a dehydrated state (DEH: USG ≥ 1.020) which was separated by 2 weeks. For the DEH trial, participants were restricted from consuming fluids for 24 hours prior to the RE and were only permitted to drink 1.5 L of water post-exercise for the remainder of the day. For the EUH trial, participants were instructed to consume fluid for 24 hours prior to and 24 hours post RE to maintain euhydration. Sleep and recovery measurements were collected from a wearable sleep device that participants wore the night before (PRE) and after RE (POST). Repeated measures ANOVAs were used to identify the differences between EUH and DEH. Effect size (ES) was calculated with resulting effects identified as either small (0.2-0.49), medium (0.5-0.79), or large (>0.8) effects. Results: Slow wave sleep (SWS) (POST EUH, 1.4±0.5 hr; POST DEH, 1.0±0.5 hr; ES=0.8; p=0.028) and %SWS (POST EUH, 21.8±3.7 %; POST DEH, 14.3±6.4 %; ES=1.4; p=0.016) were greater in DEH compared to EUH at the night following RE. Also, SWS decreased at POST compared to PRE in DEH (PRE DEH, 1.4±0.3hr; ES=1.0; p=0.028), but not in EUH (PRE EUH, 1.2±0.6 hr; p=0.061). Sleep duration, sleep effciency, sleep disturbance, sleep deprivation, rapid eye movement sleep (REM), %REM, light sleep, resting heart rate, and heart rate variability were not different between EUH and DEH ( p>0.05). Conclusion: Dehydration decreases slow wave sleep following heavy RE, which potentially impairs recovery from exercise as SWS is important for physiological recovery. Therefore, it is critical to maintain euhydration to maximize recovery following an acute bout of RE. This study was funded by National Strength and Conditioning Association (NSCA). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.