Nocturnal HRV
milliseconds
HRV recorded during sleep. Reflects the degree of parasympathetic nervous system activity and physiological recovery overnight.
Typical optimal range 45 ms - 105 ms
Population median 58 ms
Key factors
- Alcohol consumption
- Accumulated physical and occupational stress load
- Magnesium and electrolyte status
What affects this metric
- Consistent sleep timing raises it over weeks.
- Menstrual cycle phase shifts nocturnal HRV across the month.
- Cannabis lowers it in a similar pattern to alcohol.
- Alcohol is the single largest suppressor of overnight HRV.
- Late meals, late caffeine, and late training all reduce it.
- Illness and psychological stress lower it.
References
Peer-reviewed sources supporting the key factors, contributing factors, and typical optimal range shown above.
- Shaffer F, Ginsberg JP. An overview of heart rate variability metrics and norms. Frontiers in Public Health. 2017;5:258. doi.org/10.3389/fpubh.2017.00258
- Pietilä J, Helander E, Korhonen I, Myllymäki T, Kujala UM, Lindholm H. Acute effect of alcohol intake on cardiovascular autonomic regulation during the first hours of sleep. JMIR Mental Health. 2018;5(1):e23. doi.org/10.2196/mental.9519
- Schmalenberger KM, Eisenlohr-Moul TA, Jarczok MN, et al.. Menstrual cycle changes in vagally-mediated heart rate variability are associated with progesterone: evidence from two within-person studies. Journal of Clinical Medicine. 2020;9(3):617. doi.org/10.3390/jcm9030617
- Plews DJ, Laursen PB, Stanley J, Kilding AE, Buchheit M. Training adaptation and heart rate variability in elite endurance athletes: opening the door to effective monitoring. Sports Medicine. 2013;43(9):773–781. doi.org/10.1007/s40279-013-0071-8
This guide is general information, not medical advice. Talk to your clinician about your own results.