Heart rate recovery shows how fast your vagal brake comes back after effort, while resting HRV shows how active the brake is when you are still. The first-minute drop is the number to know: in a study of 2,428 adults, a fall of 12 beats a minute or less in the first minute after an exercise test went with twice the risk of death over six years (Cole and colleagues, 1999).
Two different questions
When you exercise, the vagal brake lets go and the accelerator presses. When you stop, the brake comes back first. Michael, Graham and Davis (2017) describe the first minute after exercise as the “fast phase” of recovery, usually put down to the vagal brake returning, followed by a slower phase as the accelerator eases off. They also note that HRV during exercise shrinks to a minimum at moderate effort, around 50 to 60% of maximal oxygen uptake, with RMSSD RMSSD Root mean square of successive differences: an HRV metric built from how much each heartbeat interval differs from the next, in milliseconds. It mainly reflects vagal activity. More about RMSSD falling below 5 ms.
So the two measures look at different moments:
| Resting HRV | Heart rate recovery | |
|---|---|---|
| When | At rest, usually on waking or overnight | In the first minutes after a workout |
| What it shows | How active the vagal brake is | How fast the brake returns after effort |
| What you need | A still, repeatable reading | A standard effort, done the same way |
| Day-to-day noise | About 12% for lnRMSSD lnRMSSD The natural logarithm of RMSSD, with no unit. Taking the log evens out the spread of RMSSD values, which makes day-to-day changes easier to compare and analyse. More about lnRMSSD | About 25% for the 1-minute drop; needs a fixed workout |
The model below shows why the first minute is vagal: the brake changes heart rate within a second, the accelerator over half a minute. Recovery is the same race in reverse.
How fast each nerve acts
A teaching model, not a measurement
- Delay before it moves
- 0.3 s
- Time to 90% of the change
- 1.5 s
- Rate range
- 54 to 70 bpm
Tap the vagal brake and the very next beats come later. The slowing starts within a fraction of a second and is complete within about two seconds. Let go and the rate is back just as fast.
The buttons work when JavaScript is on.
A line chart of heart rate over 50 seconds, resting at 70 beats a minute, with the press shaded from 5 to 30 seconds and a tick under the chart for every heartbeat. Tapping the brake drops the rate within about 1.5 seconds and it recovers as fast once released. Pressing the accelerator does nothing for 3.0 seconds, then the rate climbs and settles after about 21.4 seconds, and drifts back slowly after release. Pressing both slows the heart first and speeds it up later. Three buttons choose which to press, and readouts give the time to the first change and the time to settle.
What the risk study found
Cole and colleagues followed 2,428 adults, with an average age of 57, who had a treadmill test for medical reasons. They called recovery abnormal if heart rate fell by 12 beats a minute or less in the first minute after peak effort. A quarter of the group had abnormal recovery. Over six years, 213 people died. After allowing for the workload reached, heart scan results and other factors, abnormal recovery still went with twice the risk of death.
That is a link across a group of patients, measured in a clinic with a set protocol. It does not mean that a slow recovery after your run predicts anything for you.
For training
Buchheit (2014) reviewed heart-rate measures for monitoring athletes. Recovery reflects general circulation changes and the reflexes that drive the brake’s return. Some studies linked changes in the 1-minute drop with changes in performance and fatigue, but in team sports it did not always follow performance, and whether it can flag a slump the way resting HRV can is not yet confirmed. It needs a standard effort, so for team sports he suggests exercise heart rate instead: the average over the last 30 to 60 seconds of a fixed bout of at least 3 to 4 minutes, which fits into a warm-up. Exercise heart rate falls as fitness improves, but a rise on one day is not a clear sign of fatigue.
The practical combination: a morning HRV reading on most days, and recovery or exercise heart rate from a fixed warm-up or test session now and then.
When to talk to a doctor
See a doctor if exercise brings chest pain, unusual breathlessness, dizziness or fainting, or if your heart rate stays very high long after you stop. Neither recovery nor HRV can diagnose a heart problem.