Napping and heart rate variability in elite athletes

Area of Science:

• Physiology
• Sports Science
• Autonomic Nervous System Research

Background:

• Sleep and the autonomic nervous system (ANS) have a bidirectional relationship.
• Sleep influences cardiovascular activity via ANS regulation (sympathetic and parasympathetic pathways).
• Heart rate variability (HRV) analysis is a non-invasive method to assess cardiac autonomic activity.

Purpose of the Study:

• To investigate the impact of a 40-minute nap on HRV in professional basketball players.
• To assess changes in autonomic nervous system markers and subjective wellness after napping.

Main Methods:

• Twelve professional basketball players participated in a randomized crossover study with a 40-minute nap (NAP) and control (CON) condition.
• Sleep was monitored using actigraphy and sleep diaries.
• HRV was analyzed in 5-minute segments, assessing high frequency (HF), low frequency (LF), standard deviation of NN interval (SDNN), HRV index, and stress index (SI).
• Subjective measures included the Wellness Hooper index and Epworth Sleepiness Scale (ESS).

Main Results:

• No significant differences in total sleep time, time in bed, sleep efficiency, or wake after sleep onset were found between NAP and CON.
• Napping led to a significant increase in SDNN, HRV index, and LF.
• Napping resulted in a significant decrease in HF, SI, ESS, and subjective stress and fatigue scores.

Conclusions:

• A 40-minute nap effectively reduces sleepiness, stress, and fatigue in athletes.
• Napping appears to positively influence cardiac autonomic regulation, indicated by HRV changes.
• Napping may prepare the body for sympathetic nervous system reactivation post-rest, aiding recovery.