A good HRV score depends heavily on your age, fitness level, and which metric your device uses, but for the most common measurement (RMSSD), a resting value between 20 and 100 milliseconds is typical for adults. Younger, fitter people tend to land at the higher end, while values naturally decline with age. More important than any single number is your personal baseline and how it trends over time.
What HRV Actually Measures
Heart rate variability is the fluctuation in time between consecutive heartbeats. If your heart beats 60 times per minute, the gaps between beats aren’t perfectly spaced at one second each. They vary slightly, maybe 0.95 seconds, then 1.05, then 0.98. That variation is HRV, and it reflects how well your nervous system adapts to moment-by-moment demands.
The variation is controlled primarily by the vagus nerve, which runs from your brainstem to your heart and acts as the body’s brake pedal. When vagal activity is strong, it can slow your heart quickly in response to changes, creating more variation between beats. It also keeps your fight-or-flight response from overreacting, promoting a balance between the two branches of your autonomic nervous system. A higher HRV signals that your body can shift gears smoothly, ramping up when you need energy and recovering quickly when you don’t. A lower HRV suggests your nervous system is less flexible, stuck in a more rigid pattern.
Common HRV Metrics and Their Ranges
Most wearables report one of two metrics, and the numbers look very different from each other, which causes a lot of confusion.
- RMSSD is the metric used by Apple Watch, Whoop, Oura, and most consumer devices. It captures beat-to-beat variation and primarily reflects vagal (parasympathetic) activity. Typical resting values for adults range from about 20 ms to over 100 ms. A 25-year-old might average 50 to 100 ms, while a 60-year-old might sit between 15 and 40 ms.
- SDNN is more common in clinical settings and research. It reflects overall autonomic nervous system activity over a longer recording period. For a standard 24-hour recording, values above 100 ms are considered healthy, while values below 50 ms indicate significantly reduced variability.
These two metrics are not interchangeable. An RMSSD of 40 ms and an SDNN of 40 ms mean very different things. Always compare your number to reference ranges for the specific metric your device reports.
How Age and Fitness Shift the Numbers
Age is the single biggest factor. HRV peaks in your teens and twenties, then declines steadily. A “good” score for a 20-year-old would look exceptional for a 55-year-old. Population data shows that average RMSSD values drop roughly 30 to 50 percent between ages 25 and 65.
Fitness has a strong influence too. Regular aerobic exercise strengthens vagal tone over time, which directly raises HRV. Endurance athletes routinely show RMSSD values well above 100 ms. Sedentary adults of the same age often measure half that. Sex plays a smaller role: men tend to have slightly higher RMSSD values than women in younger age groups, but that gap narrows after middle age.
Because these factors vary so much, the most useful approach is to establish your own baseline over two to four weeks of consistent morning measurements, then track changes relative to that baseline rather than chasing a universal number.
Why a Higher HRV Generally Means Better Health
HRV isn’t just a fitness tracker novelty. It carries real clinical weight. A meta-analysis published in EP Europace found that people with low HRV (measured by SDNN) had roughly a 35 to 40 percent higher risk of experiencing a first cardiovascular event compared to those with high HRV, even among people with no known heart disease. The relationship followed a dose-response pattern: each 1 percent increase in SDNN corresponded to approximately a 1 percent lower risk of cardiovascular events. People at the 10th percentile of HRV had about 50 percent greater risk than the median, while those at the 90th percentile had about 33 percent lower risk.
Higher vagal tone, which drives higher HRV, is also linked to better emotional regulation, sharper cognitive performance, and stronger immune function. Research from Frontiers in Neuroscience describes how a well-functioning vagus nerve creates closer coupling between brain and heart, improving the ability to organize mental resources and adapt behavior to changing situations. People with higher resting HRV consistently perform better on working memory tasks.
What Lowers Your HRV Day to Day
Your HRV fluctuates constantly. A single reading that seems low doesn’t necessarily signal a problem. Common factors that temporarily suppress HRV include poor sleep (even one bad night can drop your score noticeably), alcohol consumption, illness or infection, intense exercise the previous day, psychological stress, and dehydration. Late meals and disrupted sleep schedules also compress the variation between heartbeats.
Chronically low HRV, where your baseline stays suppressed over weeks or months, is the pattern worth paying attention to. That can reflect ongoing stress, overtraining, sleep disorders, or underlying health conditions like diabetes, depression, or cardiovascular disease.
How to Improve Your Score
Consistent aerobic exercise is the most reliable way to raise HRV over time. You don’t need extreme training. Regular moderate activity like brisk walking, cycling, or swimming for 150 minutes per week produces meaningful improvements in vagal tone within a few months. Resistance training helps too, though the effect on HRV is smaller.
Sleep quality matters as much as exercise. Getting seven to nine hours of consistent, uninterrupted sleep is one of the fastest ways to see your morning HRV readings climb. Going to bed and waking up at roughly the same time each day strengthens the circadian rhythm that governs autonomic balance.
Slow, controlled breathing at around six breaths per minute directly stimulates the vagus nerve and can acutely raise HRV during a session. Practiced regularly, this kind of breathing exercise appears to improve resting HRV over weeks. Reducing alcohol intake, managing chronic stress, and maintaining a healthy weight all contribute as well. These aren’t quick fixes. HRV responds to sustained lifestyle patterns, not single interventions.
How to Track HRV Accurately
Wrist-based wearables have gotten reasonably accurate for tracking trends, though they’re less precise than chest straps or finger sensors for any single reading. The key is consistency in how you measure. Take readings at the same time each day, ideally first thing in the morning before getting out of bed, when your nervous system is closest to its resting state. Measurements taken after coffee, exercise, or a stressful commute will be unreliable for comparison.
Look at your seven-day rolling average rather than individual readings. A single morning measurement can swing 20 to 30 percent based on what you ate or how you slept. The trend line over weeks tells you far more than any one number. If your rolling average drops for five or more consecutive days, that’s a signal your body is under more stress than usual, whether from training load, poor recovery, illness, or psychological strain.