Is HRV higher or lower during sleep?
HRV is typically higher during sleep than when awake—often 20-30% higher than your daytime average. During rest, your parasympathetic nervous system (the "rest and digest" branch) becomes more active, allowing greater heart rate variability. This is why most wearables like Oura, Whoop, and Garmin watches measure HRV during sleep—it provides the most consistent and accurate reading, free from the noise of daily activity, posture changes, and caffeine.
What is a good sleeping HRV?
A "good" sleeping HRV depends on your age. Typical RMSSD ranges during sleep: 20s (45-90ms), 30s (40-75ms), 40s (35-60ms), 50s (30-50ms), 60+ (25-45ms). See our normal HRV by age guide for detailed percentile breakdowns. More important than absolute numbers is your personal trend—stable or gradually improving HRV over weeks indicates good recovery. Focus on your 7-day average, not single nights, since individual nights can swing 15-25% from your baseline due to normal variation.
Why Sleep HRV Matters
Sleep is when your body does its deepest recovery work, and HRV during sleep provides the clearest window into your autonomic health. Unlike daytime readings affected by activity, caffeine, and stress, sleep HRV reflects your true baseline recovery state.
Most wearables (Oura, Whoop, Garmin, Apple Watch) measure HRV during sleep for this reason. The readings are more consistent and more predictive of recovery status than daytime measurements. Athletes using HRV-guided training rely on overnight HRV to decide whether to push hard or recover on any given day. If you want to improve your HRV, optimizing sleep quality is typically the highest-return intervention.
When HRV is Measured During Sleep
Different devices measure at different times, which is why numbers from different platforms are not directly comparable:
During deep sleep (Oura, Whoop): HRV is measured during your most restorative sleep phases, typically in the first half of the night. This captures peak parasympathetic activity and tends to produce higher, more stable readings.
Throughout the night (Garmin): Samples are taken periodically and averaged, giving a broader picture but potentially more night-to-night variability.
Night average (most devices): The number you see in the morning is usually an average or representative sample, not a single reading. Some devices like the Apple Watch report the lowest overnight value instead.
For reliable baselines, research suggests you need at least 5 nights of data. Stick with one device and one measurement method to keep your trend data meaningful.
Average Sleeping HRV by Age
Sleep HRV tends to be 15-30% higher than waking HRV because your parasympathetic system is more active at rest. Typical RMSSD ranges during sleep:
- 20s: 45-90ms average
- 30s: 40-75ms average
- 40s: 35-60ms average
- 50s: 30-50ms average
- 60+: 25-45ms average
These are rough averages—individual variation is significant. Fit individuals often score in the upper range or above for their age group, while sedentary individuals trend lower. Your personal trend matters more than comparing to population norms. For detailed daytime benchmarks and percentile data, see our normal HRV by age guide.
What Affects Sleep HRV
Factors that lower sleep HRV: - Alcohol (even 1-2 drinks suppress sleep HRV by 10-20%) - Late eating (within 2-3 hours of bed raises overnight heart rate by 5-10 BPM) - Poor sleep environment (temperatures above 70F/21C, noise, or ambient light) - Stress and anxiety (elevated cortisol prevents parasympathetic dominance) - Illness or fighting infection (HRV often drops 1-3 days before symptoms appear) - Hard training that day (especially high-intensity or long-duration sessions) - Sleep disorders (apnea, restless legs)
Factors that raise sleep HRV: - Consistent sleep schedule (same bedtime within 30 minutes each night) - Cool, dark bedroom (65-68F/18-20C is the optimal range) - Good sleep hygiene (screens off 1 hour before bed, dark environment) - Regular exercise (not within 3 hours of bedtime) - Stress management and evening wind-down routines - Recovery days after hard training
Sleep HRV Patterns to Watch
Healthy pattern: HRV is highest in the first part of the night during deep sleep, then may decline slightly toward morning as you cycle through lighter sleep phases. A well-recovered person typically shows their peak HRV during the first 3-4 hours of sleep.
Warning signs: - HRV that's suppressed all night (poor recovery—may indicate overtraining) - Large night-to-night swings greater than 25-30% (inconsistent sleep quality) - Steady decline in your 7-day average over 2+ weeks (accumulating stress or fatigue) - Readings consistently 20%+ below your personal baseline
Good sign: HRV rebounds after rest days, returning to or exceeding baseline. This bounce-back pattern indicates healthy autonomic flexibility. If your HRV does not rebound after 2-3 recovery days, review our guide on why HRV isn't improving for troubleshooting steps.
Improving Your Sleep HRV
The same factors that improve sleep quality improve sleep HRV. Prioritize these changes roughly in order of impact:
- Consistent schedule: Same bedtime and wake time, even weekends (within 30 minutes)
- No alcohol: Or at least none within 4 hours of bed—this is the single biggest sleep HRV killer for most people
- Cool room: 65-68°F (18-20°C) is optimal for most people
- Early dinner: Finish eating 3+ hours before bed to avoid a 5-10 BPM heart rate increase overnight
- Wind down: Reduce screens and stimulation in the hour before sleep
- Morning exercise: Better for sleep HRV than evening workouts, which can elevate heart rate into the night
- Address sleep disorders: Apnea significantly suppresses HRV and is often undiagnosed
Improvements typically appear within 1-2 weeks of consistent changes. Start with just one or two adjustments and track the impact on your 7-day average.
Research: A 2025 meta-analysis confirmed that even one night of poor sleep significantly reduces HRV. Browse sleep and HRV studies for more findings on sleep quality and heart rate variability.
Sleep HRV as Health Predictor
Recent research shows sleep HRV patterns can predict future health conditions, making long-term tracking especially valuable:
A 2025 study of 4,000+ individuals found that sleep HRV patterns predicted stroke, depression, and cognitive dysfunction years before diagnosis. Unusually high and erratic HRV predicted stroke risk, while persistently low HRV was common in those who later developed depression. These findings highlight why monitoring your normal HRV by age over months and years matters.
For athletes, pre-sleep HRV can predict insomnia with 96% accuracy—suggesting that calming practices like resonance breathing before bed may help those who struggle with sleep onset. Even 5 minutes of slow breathing at 6 breaths per minute can shift your nervous system toward parasympathetic dominance before you fall asleep.
Best Devices for Sleep HRV
Rings (most comfortable for sleep): - Oura Ring: Industry-leading sleep analysis + HRV - Ultrahuman Ring: No subscription, full sleep metrics - Samsung Galaxy Ring: Good Samsung ecosystem integration
Wrist wearables: - Whoop: 24/7 tracking with sleep coaching - Garmin watches: Sleep score + HRV - Fitbit Sense 2: Sleep stages + HRV
Bed sensors (most unobtrusive): - Emfit QS+Active: Under-mattress sensor, no wearable needed - Great for people who don't want to wear anything to bed - Clinical-grade accuracy for research applications
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