Summary
HRV varies predictably throughout the day, with highest values typically during sleep and lowest during afternoon hours. Consistent measurement timing is essential for meaningful comparisons.
Methods
24-hour continuous HRV monitoring studies
Key Findings
- HRV peaks during deep sleep (2-4 AM typically)
- Lowest HRV typically 2-4 PM
- Individual patterns are consistent day-to-day
- Variation of 20-40% normal between morning and afternoon
Limitations
Individual chronotypes may shift these patterns
What This Means for You
Always measure HRV at the same time for valid comparisons. A reading taken at 6 AM will be very different from one at 3 PM, even on the same day. Morning measurements are most commonly recommended.
Source
Read the original paper in Autonomic Neuroscience ↗
Added to HRV Zone: 2025-01-09