Does Wearable-Measured Heart Rate Variability During Sleep Predict Perceived Morning Mental and Physical Fitness?

Area of Science:

• Psychophysiology
• Wearable Sensor Technology
• Military Health

Background:

• Wearable sensors enable automated psychophysiological marker measurement for personalized feedback.
• Assessing mental and physical fitness is crucial for military personnel.
• Heart Rate Variability (HRV) is a key psychophysiological marker.

Purpose of the Study:

• To investigate the predictive power of resting heart rate variability (HRV) during sleep on subsequent morning perceived mental and physical fitness in military personnel.
• To explore the utility of wearable sensor data for automated fitness assessment.

Main Methods:

• Participants (N=63) wore Garmin wrist-worn wearables for up to 46 days.
• Heart rate and accelerometer data were collected via a custom smartphone app.
• Open-source algorithms were used for sleep detection and artifact filtering; linear mixed models analyzed 571 observations.

Main Results:

• Resting HRV during sleep was a small predictor of perceived physical fitness (marginal R² = .031).
• Resting HRV did not significantly predict perceived mental fitness.
• Perceived mental and physical fitness items were highly correlated (r = .77).

Conclusions:

• Resting HRV during sleep is more associated with the physical component of perceived fitness than the mental component.
• Wearable technology shows potential for monitoring physical fitness, but further research is needed for mental fitness prediction.
• Future studies should refine sleep and HRV measurement and explore HRV's role in stress buffering.