Your usual range
Pajdo compares your numbers with your own recent days, not with everyone else's. Your usual range is your typical value plus its everyday wobble.
Bodies differ a lot. In a study of more than 92,000 adults, people's typical resting heart rate ran from about 40 to over 100 bpm, and age, sex, body size and sleep together explained only a small part of that gap. Yet each person stayed fairly steady: most moved by only about 3 bpm within a week.
So Pajdo compares you with you. For most metrics he takes the 28 days before the days he's looking at and works out two things: your average and how much you usually vary around it. HRV gets 60 days, because Apple Watch samples it only while you're still, so readings come unevenly. Sports scientists read heart rate and HRV the same way: a change matters when it's bigger than that person's own day-to-day noise.
A day sits outside your usual range only when it's further from your average than your everyday wobble explains, and usually by a minimum amount too (for resting heart rate, 3 bpm). That keeps tiny changes in a very steady person from setting anything off.
Worth a try
Keep up regular endurance exercise
A meta-analysis of 191 studies in healthy people found that exercise lowered resting heart rate. Endurance training and yoga showed the clearest effect in both men and women.
It's a slow change, and plenty of things nudge daily readings around, so look at the trend rather than one morning.
Try it: pick an endurance activity you like, such as brisk walking, cycling or swimming, and do it on most days for a couple of months. Then check the resting heart rate trend from Apple Watch in Pajdo.
Habits that support HRV
A meta-analysis of trials in healthy adults found that exercise training, kept up for weeks to months, raised HRV compared with not training. Walking, running, cycling and yoga all counted.
Alcohol pulls the other way. In a study of over 4,000 people, even a small amount was linked to lower HRV in the first hours of sleep. Some studies suggest losing sleep nudges it down too, though results are mixed.
HRV varies with age, sex and fitness, so compare it with your own usual.
Try it: pick a workout you like, do it a few times a week for a couple of months, and watch your HRV trend in Pajdo.
Keep reading
Sources
- Inter- and intraindividual variability in daily resting heart rate and its associations with age, sex, sleep, BMI, and time of year, PLOS ONE (Quer et al. 2020)
- Monitoring training status with HR measures: do all roads lead to Rome?, Frontiers in Physiology (Buchheit 2014)
- Monitor your heart rate with Apple Watch, Apple Support
- Effects of exercise on the resting heart rate: a systematic review and meta-analysis of interventional studies (Reimers, Knapp and Reimers 2018), Journal of Clinical Medicine
- Effects of exercise training on heart rate variability in healthy adults: a systematic review and meta-analysis of randomized controlled trials (Amekran and El hangouche 2024), Cureus
- Acute effect of alcohol intake on cardiovascular autonomic regulation during the first hours of sleep: observational study (Pietilä et al. 2018, 4,098 employees), JMIR Mental Health
- Effects of sleep deprivation on heart rate variability: a systematic review and meta-analysis (Zhang et al. 2025), Frontiers in Neurology
- An overview of heart rate variability metrics and norms (Shaffer and Ginsberg 2017), Frontiers in Public Health
Checked against these sources on October 11, 2026.
This is general wellness information, not medical advice. If a number worries you, or stays away from your usual for a while, talk to a doctor.