Effect of evening postexercise cold water immersion on subsequent sleep

Area of Science:

• Sports Science
• Sleep Research
• Exercise Physiology

Background:

• Optimizing recovery after exercise is crucial for athletic performance.
• The impact of post-exercise cooling strategies on sleep remains an area of interest.
• Understanding how evening exercise and cold water immersion influence sleep is important for athletes.

Purpose of the Study:

• To investigate the effects of cold water immersion (CWI) following evening exercise on sleep quality and quantity.
• To determine if CWI alters sleep architecture compared to exercise alone or a control condition.
• To assess physiological responses, including temperature and heart rate, during sleep after evening exercise and CWI.

Main Methods:

• Male cyclists (n=11) participated in three conditions: control (CON), exercise only (EX), and exercise followed by CWI.
• Exercise involved cycling at high intensity, followed by a maximal time trial.
• Laboratory-based polysomnography was used to measure sleep architecture, alongside continuous monitoring of core and skin temperature, heart rate, and salivary melatonin.

Main Results:

• No significant differences were found in total sleep time, sleep efficiency, or sleep stage distribution between CON, EX, and CWI conditions.
• Core body temperature decreased below control levels during a period in the CWI trial, but overall nocturnal temperature profiles were similar.
• Post-exercise heart rate remained elevated until bedtime in both EX and CWI, while skin temperature was lower after CWI.

Conclusions:

• Evening exercise, whether followed by cold water immersion or not, does not alter the overall architecture of sleep in trained cyclists.
• Cold water immersion does not appear to confer additional benefits or detriments to sleep quality or quantity after strenuous evening exercise.
• Sleep physiology in trained athletes is robust to the acute effects of evening exercise and associated cooling interventions.