Effect of the Depth of Cold Water Immersion on Sleep Architecture and Recovery Among Well-Trained Male Endurance Runners

Front Sports Act Living. 2021; 3: 659990.

Published online 2021 Mar 31. doi: 10.3389/fspor.2021.659990

Maxime Chauvineau, Florane Pasquier, Vincent Guyot, Anis Aloulou, and Mathieu Nedelec*

This study looks at the effect of the depth of cold-water immersion on sleep architecture and recovery among well-trained male endurance athletes.
Whole-body immersion including the head for 10 minutes following an intensive run resulted in significantly higher proportion of slow-wave sleep during the first 180 min of the night compared to those partially immersed in cold water (up to the hip).

WHOLE and PARTIAL induced a significant decrease in arousal for the duration of the night compared with CONTROL, while only WHOLE decreased limb movements compared with CONTROL.

No significant differences between conditions were observed for any markers of fatigue and muscle damage throughout the 48-h recovery period.
More research is needed to determine if positive sleep outcomes result in overall recovery optimisation for athletes.

ABSTRACT

Introduction: The aim of the present study was to investigate the effect of the depth of cold water immersion (CWI) (whole-body with head immersed and partial-body CWI) after high-intensity, intermittent running exercise on sleep architecture and recovery kinetics among well-trained runners.

Methods: In a randomized, counterbalanced order, 12 well-trained male endurance runners (V.O2max = 66.0 ± 3.9 ml·min−1·kg−1) performed a simulated trail (≈18:00) on a motorized treadmill followed by CWI (13.3 ± 0.2°C) for 10 min: whole-body immersion including the head (WHOLE; n = 12), partial-body immersion up to the iliac crest (PARTIAL; n = 12), and, finally, an out-of-water control condition (CONT; n = 10). Markers of fatigue and muscle damage—maximal voluntary isometric contraction (MVIC), countermovement jump (CMJ), plasma creatine kinase [CK], and subjective ratings—were recorded until 48 h after the simulated trail. After each condition, nocturnal core body temperature (Tcore) was measured, whereas sleep and heart rate variability were assessed using polysomnography.

Results: There was a lower Tcore induced by WHOLE than CONT from the end of immersion to 80 min after the start of immersion (p < 0.05). Slow-wave sleep (SWS) proportion was higher (p < 0.05) during the first 180 min of the night in WHOLE compared with PARTIAL. WHOLE and PARTIAL induced a significant (p < 0.05) decrease in arousal for the duration of the night compared with CONT, while only WHOLE decreased limb movements compared with CONT (p < 0.01) for the duration of the night. Heart rate variability analysis showed a significant reduction (p < 0.05) in RMSSD, low frequency (LF), and high frequency (HF) in WHOLE compared with both PARTIAL and CONT during the first sequence of SWS. No differences between conditions were observed for any markers of fatigue and muscle damage (p > 0.05) throughout the 48-h recovery period.

Conclusion: WHOLE reduced arousal and limb movement and enhanced SWS proportion during the first part of the night, which may be particularly useful in the athlete's recovery process after exercise. Future studies are, however, required to assess whether such positive sleep outcomes may result in overall recovery optimization.

Keywords: polysomnography, muscle damage, core body temperature, heart rate variability, slow-wave sleep, performance, limb movements, arousals