Resting Heart Rate and Fitness: What Changes as You Train
Resting heart rate is the number of times your heart beats per minute when you are completely at rest, and for most adults it sits somewhere between 60 and 100 beats per minute. As your aerobic fitness improves, it often drifts lower, because a fitter heart pumps more blood with each beat and needs fewer beats to do the same job. It is a useful trend to watch, but a noisy one: sleep, alcohol, stress, caffeine and illness all push it around day to day. This piece explains how to measure it properly, what tends to change as you train, what the number cannot tell you, and when a reading is worth taking to your GP.
What the number reflects
Your heart pumps a certain volume of blood with each beat, known as stroke volume. Regular aerobic exercise tends to increase that volume over time. If each beat moves more blood, the heart needs fewer beats at rest to supply the body, so the resting rate falls. That is the simple version, and it is why endurance athletes are known for low resting rates.
But resting heart rate is also shaped by things that have nothing to do with fitness: genetics, age, medication (beta blockers lower it, for example), body temperature, hydration and the state of your nervous system. Two people of identical fitness can have quite different numbers. So it is most useful as a comparison against yourself, not against other people.
How to measure it properly
A single reading taken after rushing up the stairs at Highgate station tells you very little. For a number you can trust, be consistent.
- Measure first thing in the morning, after waking and before coffee or getting out of bed if you can.
- Find your pulse on the inside of your wrist, below the base of the thumb, using two fingers rather than your thumb. The British Heart Foundation has a clear guide.
- Count the beats for a full 60 seconds, or for 30 seconds and double it.
- Do it on several mornings and look at the average rather than any single day.
- Note anything unusual: a late night, alcohol, a cold coming on.
A wearable measured overnight does much the same job and is less effort. Different devices measure and define “resting” differently, so compare your device with itself over time rather than with someone else’s. We have looked at the wider question of how much to trust these devices in what your recovery score actually means.
What tends to change as you train
The direction of travel is reasonably predictable; the size and speed are not. A few patterns are worth knowing.
- Aerobic work moves it most. Steady cardio such as brisk walking, cycling, rowing or easy running, done regularly over weeks and months, has the clearest effect. We go into that kind of training in zone 2 cardio.
- Strength training helps too, though usually less directly. A sensible programme combines both, which is also what the NHS activity guidelines recommend: 150 minutes of moderate activity a week plus strengthening on at least two days.
- The change is gradual. Think months, not weeks. Day-to-day noise is often larger than the month-to-month trend, which is why the average matters.
- It reverses with a long break. Stop training for a while and it tends to drift back up. Resume, and it tends to come back down.
Another useful marker is how quickly your heart rate comes down after effort. After a hard interval on the air bike, a fitter person’s heart rate typically drops faster in the first minute or two of rest. You don’t need a lab to notice this; you will feel yourself recovering between efforts sooner.
Why it jumps, and what to do about it
If your morning reading is noticeably higher than your usual average for a few days running, something is usually going on. Common culprits:
| Likely cause | What you might notice | Sensible response |
|---|---|---|
| Poor or short sleep | Higher reading, heavy legs, low mood | Keep the session but lighter; prioritise sleep that week |
| Alcohol the night before | Higher reading the next morning | Expect it; don’t read anything into a single day |
| Work stress | Raised for several days, poor sleep | Keep training moderate; don’t add intensity |
| Illness coming on | Raised reading, feeling run down | Rest. Train again once you feel well |
| Too much hard training | Raised for a week or more, performance dropping | Reduce volume; see signs of overtraining |
| Heat, dehydration, caffeine | Short-lived rise | Measure at the same time, before coffee |
A single high reading is not a signal. A pattern over several days, especially alongside feeling unwell or a drop in performance, is worth acting on by easing off.
What resting heart rate can’t tell you
It is tempting to treat a falling number as proof of fitness and a rising one as failure. Neither holds up on its own. Resting heart rate says nothing directly about your strength, your body composition or how well you move. Someone could lower their resting rate with lots of walking and still have very little muscle. Someone else could gain real strength without much change in the number.
Use it alongside other measures: what you lift and for how many reps, how a set distance on the bike feels, and body composition, which the InBody scanner in our studio estimates by separating muscle from fat.
When to talk to your GP
This is a fitness article, not medical advice. Speak to your GP if your resting heart rate is regularly above 100 or below 60 and you are not a trained endurance athlete, if your pulse feels irregular, or if you notice palpitations, dizziness, breathlessness, chest pain or fainting. If you have chest pain or feel very unwell, call 999. Check with your GP first before starting training if you have a known heart condition or take medication that affects heart rate.
Training with heart rate in mind
In the private studio at The Highgate House on Archway Road, Highgate, sessions combine strength work on the rack and cable station with conditioning on the air bike. If you track your heart rate with a wearable, bring the data: it is a sensible thing to look at alongside the training log when reviewing a block. The personal training page explains how sessions run.
Questions we get asked
What is a good resting heart rate?
For most adults, 60 to 100 is considered normal. Lower within that range often reflects good aerobic fitness, but your own trend over time matters more than comparing with anyone else.
How quickly will mine drop?
There is no reliable timeline. It depends on your starting point, how much aerobic work you do and many other factors. Expect gradual change over months.
Is my smartwatch accurate?
Wrist devices are usually reasonable at rest and less accurate during hard or jerky exercise. Consistency matters more than precision for tracking trends.
Should I train if my heart rate is high this morning?
If you feel fine, a lighter session is usually sensible. If you feel unwell, rest. Tell your coach at the start of the session so the plan can be adjusted.
Book with The Highgate House
Ready to start training properly? Email us at [email protected] with the service and the day that suits you, and we will come back to you with times.
Visit The Highgate House · Private personal training
The Highgate House, Archway Road, Highgate, London N6.
