A good HRV on Apple Watch generally falls between 50 and 100 milliseconds if you’re in your 20s, and between 35 and 60 milliseconds if you’re in your mid-40s. But “good” is relative. HRV varies so much by age, sex, and fitness level that your personal baseline matters far more than any universal number.
What Apple Watch Actually Measures
Your Apple Watch reports HRV using a metric called SDNN, which captures the variation in time between heartbeats measured in milliseconds. A higher number means more variation, which, counterintuitively, is the healthier result. It reflects your nervous system’s ability to shift gears between stress mode and recovery mode on demand.
The watch takes these readings periodically throughout the day using green LED lights on the back of the sensor. It measures during still moments, walks, workouts, and breathing sessions. Because readings happen based on your activity level, they aren’t evenly spaced, and the timing between measurements varies. You’ll find your HRV data in the Health app under Heart, where Apple displays it alongside trends over days, weeks, and months.
Average HRV by Age and Sex
HRV declines steadily with age, which is the single biggest factor in what counts as “normal.” Based on data from large wearable populations, here’s what the middle range looks like:
- 25-year-old males: roughly 50 to 100 ms
- 25-year-old females: roughly 45 to 90 ms
- 45-year-old males: roughly 35 to 60 ms
- 45-year-old females: roughly 30 to 55 ms
Across all ages, the overall average for men is around 65 ms and for women is around 62 ms. If you’re significantly below these ranges for your age group, it may reflect chronic stress, poor sleep, low fitness, or a combination. If you’re above them, that typically signals strong cardiovascular fitness and good recovery capacity.
Why Your Personal Baseline Matters Most
Comparing your HRV to population averages gives you a rough sense of where you stand, but the real value comes from tracking your own trends over time. Someone with a resting HRV of 45 ms who sees it climb to 55 ms over several months of consistent exercise has gained meaningful ground, even if they never reach 80 ms. The direction of your trend tells you more than any single reading.
Day-to-day swings are completely normal. A poor night of sleep, a hard workout, alcohol, or a stressful day can all temporarily drop your HRV. What you’re watching for is whether your seven-day or 30-day average is gradually rising, holding steady, or declining. A sustained drop over weeks, especially one you can’t explain with obvious lifestyle factors, is worth paying attention to.
What High and Low HRV Tell You
HRV is really a window into your autonomic nervous system, the part of your brain that runs on autopilot and controls heart rate, breathing, blood pressure, and digestion. It has two branches: one that ramps you up for stress, and one that brings you back down for recovery. When both branches are working well and flexibly trading off, HRV tends to be higher.
People with higher HRV generally have better cardiovascular fitness and handle stress more effectively. Low HRV is associated with increased risk of cardiovascular disease and often reflects a nervous system stuck in stress mode. Chronic stress, poor sleep, sedentary habits, and an unhealthy diet can all push that stress branch into overdrive, suppressing the recovery side and dragging HRV down.
How Accurate Is the Apple Watch?
Apple Watch HRV readings are useful for tracking trends, but they aren’t as precise as medical-grade equipment. A 2024 study comparing the Apple Watch Series 9 and Ultra 2 against a validated chest strap found that the watch tended to underestimate HRV by about 8 ms on average. The individual readings could be off by around 20 ms in either direction, and the measurements didn’t fall within a strict clinical accuracy window of plus or minus 10 ms.
What this means in practice: don’t obsess over whether today’s reading is 52 or 58. That level of precision is beyond what the wrist sensor can reliably deliver. But if your weekly average shifts from 55 to 70 over a couple of months, that’s a real signal. The Apple Watch is best used as a trend-tracking tool, not a diagnostic one.
How to Raise Your HRV
The most effective lever is regular aerobic exercise. Jogging, swimming, cycling, or even brisk walking all promote a healthier balance between the stress and recovery branches of your nervous system. The key is consistency without overdoing it. Overtraining can actually suppress HRV, so gradually increasing intensity works better than pushing to exhaustion.
Sleep quality is the second major factor. Maintaining a consistent sleep schedule, keeping your bedroom dark and cool, and cutting screen time before bed all contribute to better overnight recovery, which is when your body does its deepest parasympathetic work. Many people notice their HRV improves noticeably after just a few weeks of better sleep habits.
Stress management rounds out the picture. Controlled breathing exercises are particularly effective because they directly stimulate the recovery side of your nervous system. A simple technique called box breathing (inhale for four counts, hold for four, exhale for four, hold for four) practiced for just a few minutes can shift your nervous system toward recovery mode. Regular meditation and yoga work through similar mechanisms.
Hydration and nutrition play supporting roles. Staying well-hydrated and eating a diet rich in fruits, vegetables, whole grains, and healthy fats gives your cardiovascular system the raw materials it needs to function optimally. None of these changes produce overnight results, but most people who consistently improve their sleep, exercise, and stress habits see their HRV baseline climb over weeks to months.