WHOOP's own data puts typical HRV for 20 to 25 year olds at roughly 55 to 105 ms and for 60 to 65 year olds at roughly 25 to 45 ms, but those ranges are wide for a reason. HRV varies so much between people that comparing your number with someone else's tells you very little. A "good" HRV is one that's stable or rising against your own baseline.
You open the app, see an HRV of 38 and then scroll past a friend's screenshot showing 110. It's hard not to wonder whether something is wrong with you.
Usually, nothing is. HRV is one of the most personal numbers your strap records, and the question "what is a good HRV?" has a much better answer than a single target.
What WHOOP's HRV number actually is
Heart rate variability is the variation in time between your heartbeats, measured in milliseconds. It reflects how your autonomic nervous system is balancing stress and recovery, and a lower HRV can mean your body is working harder because of fatigue, stress, dehydration or illness (WHOOP).
WHOOP doesn't use a reading from the middle of your day. It calculates HRV during your deepest sleep each night, when your body is most stable (WHOOP). A WHOOP study published in PLOS ONE describes the method in more detail: the strap uses rMSSD, a standard HRV measure, taken during slow-wave sleep (Miller et al., 2020).
That detail matters. HRV taken at a different time of night, over a different window or with a different method can give a different number. A large review of published HRV values found that methodological differences were behind many of the disparate numbers reported in healthy adults (Nunan et al., 2010). So a number from another device, or from a morning chest-strap reading, isn't directly comparable with your WHOOP number.
The averages by age, and what they leave out
WHOOP publishes ranges from its own members. The middle 50% of 20 to 25 year olds usually fall between 55 and 105 ms, while 60 to 65 year olds are normally between 25 and 45 ms. The average across all members is 65 ms for men and 62 ms for women. By age, it's 78 ms at 25, 60 ms at 35, 48 ms at 45 and 44 ms at 55 (WHOOP).
Two things stand out. First, HRV tends to fall with age, so a 50-year-old comparing themselves with a 25-year-old is comparing apples with oranges. Second, these are WHOOP members, who WHOOP notes tend to be athletes and health-conscious people. That's not a picture of the general population.
The ranges are also wide. "The middle 50%" means a quarter of members in each age group sit below the range and a quarter sit above it.
Why comparing with other people misleads
HRV differs hugely from one person to the next. The same review of normal values found that some HRV measures varied between individuals by up to 260,000% (Nunan et al., 2010). Some of that is method, but much of it is just people being different.
Part of it is inherited. A Framingham Heart Study analysis estimated that genetic factors explained 13% to 23% of the variation in HRV measures (Singh et al., 1999). Age, sex, fitness, lifestyle and environment all play a part as well (WHOOP).
Fitness doesn't guarantee a high number either. WHOOP points out that many exceptionally fit people have HRV lower than the norm (WHOOP). WHOOP also notes that plenty of extremely fit people regularly have HRV in the 40s (WHOOP). If that's you and you feel well, it may simply be your normal.
What "good" looks like in your own data
If comparing with others doesn't work, what does? WHOOP's own answer is that a good HRV for you is one that's stable or trending upward over time, and that a sustained downward trend is the thing to watch (WHOOP).
Sports scientists who monitor athletes' HRV approach it the same way:
- Use a rolling average. Researchers recommend a 7-day rolling average rather than single days, because it smooths out normal night-to-night noise and makes the real trend visible (Plews et al., 2013).
- Watch the day-to-day swing as well as the average. In a case study of two elite triathletes, the athlete who became overreached showed a falling 7-day HRV average and a shrinking day-to-day variation as it happened, while the other athlete's numbers stayed stable (Plews et al., 2012). That's two people, so it's a hint, not a rule.
- Expect noise. Even Olympic water polo players wearing WHOOP straps showed normal night-to-night wobble in HRV (Bellenger et al., 2022). One low morning is not a trend.
In practice, a "good" HRV looks like a steady band you recognise, with dips that line up with hard training, a big night out or a stressful week, and that come back within a few days. Those dips are also what a recovery forecast tries to see coming; here's how far you can predict tomorrow's WHOOP recovery.
Can you raise your HRV?
Often, yes, though within limits set by age and genetics. A meta-analysis of exercise training studies found that training increased a vagal HRV measure, with a smaller effect in older people (Sandercock et al., 2005). WHOOP reports that in a four-month study, collegiate athletes on WHOOP saw their HRV rise by an average of 8.3 ms (WHOOP).
The habits that pull HRV down are well known. WHOOP lists intense exercise, dehydration, alcohol, eating late, illness, psychological stress and inconsistent sleep schedules among common causes (WHOOP). Alcohol stands out: in aggregated WHOOP member data, even a single drink was linked to HRV dropping by about 7 ms on average (WHOOP). We cover dose, timing and the days after in how long alcohol affects WHOOP recovery.
The most reliable way to find out what moves your HRV is to change one thing at a time for a couple of weeks and compare it with your own baseline, rather than copying someone else's routine. Sleep timing is a good place to start, and we explain why in WHOOP sleep consistency and recovery.
When a low number is worth a closer look
A single low HRV reading isn't a cause for alarm (WHOOP). The situations worth paying attention to are different:
- A low reading after a good night's sleep. This is common and usually has a cause you can find. We cover it in why your WHOOP recovery can be low after a good night's sleep.
- A slow slide over a week or more while your training load climbs. That's often a sign to back off. See when to deload using 7- vs 28-day strain and HRV trends. For the day-to-day call, here's what strain to aim for on WHOOP.
- HRV dropping while resting heart rate, respiratory rate or skin temperature also move. That combination can show up when your body is fighting something. See can WHOOP tell you're getting sick, and for the way back, when to train again after being sick.
If your HRV stays well below your usual range and you also feel unwell, talk to a qualified professional.
Frequently asked questions
WHOOP's member data puts the middle 50% at roughly 55 to 105 ms for ages 20 to 25 and 25 to 45 ms for ages 60 to 65, with averages of 78 ms at 25, 60 ms at 35, 48 ms at 45 and 44 ms at 55. Those are useful context, but your own baseline is the better comparison.
Not necessarily. Plenty of healthy, fit people have HRV in that range, especially as they get older. What matters more is whether 40 is normal for you and whether your trend is stable.
HRV varies hugely between people because of genetics, age, sex, fitness and lifestyle. Different devices and measurement methods can also give different numbers, so comparing across people or devices tells you very little.
Higher HRV is generally linked with better fitness and recovery, but chasing a number isn't the goal. A stable or rising trend against your own baseline is a better sign than any single high reading.
It depends on the person and the change. In one WHOOP study, collegiate athletes saw an average rise of 8.3 ms over four months. Changes from habits like cutting alcohol can show up much sooner, but they're easiest to judge over a couple of weeks.
This article is general information, not medical advice. If something feels off, talk to a qualified professional.
See your HRV against your own normal
Population charts tell you where you stand among strangers. What you actually need to know each morning is where today's HRV stands against your own normal, and what to do about it.
That's one of the reasons we built ZONAL, a free web app in beta that works with WHOOP through a read-only WHOOP sign-in. It compares your signals with your own normal from your recent healthy mornings, and turns them into a daily train or ease-off call. It also gives you a recovery forecast for tomorrow, and Signal watch, which looks for early illness signs using skin temperature alongside HRV, resting heart rate, breathing rate and blood oxygen. If you want to know whether a habit is really moving your HRV, you can run an Experiment and see what changes in your own data.
If you'd like to stop comparing your HRV with everyone else's, you can try ZONAL free while it's in beta.
ZONAL is an independent app that works with WHOOP through a read-only WHOOP sign-in. It is not affiliated with, endorsed by, or sponsored by WHOOP, Inc. WHOOP is a trademark of WHOOP, Inc.
