Neither one matters more. HRV reacts more strongly to everyday strain such as hard training, while resting heart rate Resting heart rate How many times your heart beats per minute while you are fully at rest. For adults it is usually 60 to 100 beats per minute, and lower in well-trained athletes. More about Resting heart rate moves less but rises clearly with bigger stressors such as illness or heavy drinking. Because the two are linked, they are most useful when you read them together.
How the two are connected
Resting heart rate counts beats per minute. HRV measures how much the time between beats changes from one beat to the next. The heartbeat lesson shows both on one picture.
The two are tied together in two ways, as Jerzy Sacha explains in a 2014 review. First, the same nervous system controls both. The “ rest and digest Parasympathetic nervous system The "rest and digest" branch of the autonomic nervous system. It slows the heart, mainly through the vagus nerve, and drives most of the beat-to-beat variation in HRV. More about Parasympathetic nervous system ” side slows the heart and also adds variation between beats. Second, there is simple maths. The gap between beats is 60,000 ms divided by heart rate, and that is not a straight line:
- At 60 beats per minute, the average gap is 1,000 ms. At 61, it is about 984 ms, a difference of 16 ms.
- At 120 beats per minute, the gap is 500 ms. At 121, it is about 496 ms, a difference of only 4 ms.
So the same small wobble in heart rate creates bigger gaps between beats when your heart is slow. This is one reason HRV tends to be higher when resting heart rate is lower. Sacha advises taking heart rate into account whenever you compare HRV readings.
What each one is good at
Altini and Plews studied 28,175 people who took a one-minute morning reading with a phone app, on average for almost a year each. They compared how each measure changed after common stressors, relative to each person’s usual values:
| Stressor | Resting heart rate | HRV ( RMSSD RMSSD Root mean square of successive differences: an HRV metric built from how much each heartbeat interval differs from the next. It mainly reflects vagal activity. More about RMSSD ) |
|---|---|---|
| Day after hard training | about 1% higher | about 4.8% lower |
| Day after high alcohol intake | 6% higher | 12% lower |
| While sick | 6% higher | 10% lower |
HRV changed by larger percentages each time. The authors called it the more sensitive marker, but not a specific one, because many different things move it. They suggested HRV may suit decisions about training, while resting heart rate may be better for spotting bigger stressors such as illness. For more on that, see can HRV warn you that you’re getting sick?
Larger changes do not make HRV less noisy. Buchheit’s review of athlete monitoring lists a typical day-to-day error of about 10% for resting heart rate and about 12% for HRV (as the log of RMSSD). The two have a similar balance of signal and noise.
The two also differ between people. In the same app data, HRV fell with age while resting heart rate did not. Resting heart rate was more closely linked to how active people were.
How to read them together
Buchheit recommends judging HRV next to resting heart rate. Some common patterns:
- HRV up, heart rate down: usually a sign you are coping well with training.
- HRV down, heart rate up: the pattern seen after hard training, heavy drinking and illness in the app data above.
- Heart rate clearly up, whatever HRV does: worth watching, since bigger stressors such as illness show up clearly in resting heart rate.
Go deeper When both fall together in very fit people
In athletes with very low resting heart rates, HRV can drop while heart rate also drops. Buchheit explains this as a saturation effect. Very strong “rest and digest” activity holds the heart so steady that the beat-to-beat swings shrink. Here the lower HRV comes with more parasympathetic activity, not less. This is one reason coaches look at both numbers.
Use your seven-day averages, not single days, and compare each with your own usual range. If you feel unwell, trust that over either number. See why your HRV can be good when you feel tired.
When to talk to a doctor
Talk to a doctor if your resting heart rate stays well above your usual level for several days with no clear cause, or if a change in either number comes with chest pain, breathlessness, dizziness or fainting. Neither number can diagnose a heart problem.