Despite how fundamental they are to our existence, most of us rarely think about our heartbeats until, say, a surge of adrenaline causes us to become conscious of the fluttering in our chests. Beats are also noticeably faster in moments of stress or excitement, after we’ve consumed caffeine and when we exercise. This has led some to speculate that overdoing it at the gym or performing other intense physical activities effectively burns through a heartbeat reservoir, shortening our lifespan.

“It is likely that this notion that we are born with a fixed number of heartbeats comes from early physiological observations across mammalian species where scientists noticed that smaller animals with faster heart rates tended to have shorter lifespans,” says Tim van Puyvelde, a cardiologist at the KU Leuven research university in Belgium.

This “finite heartbeat theory” has been perpetuated by, among others, the US president Donald Trump. In their 2016 book Trump Revealed, the Washington Post journalists Michael Kranish and Marc Fisher noted: “Trump believed the human body was like a battery, with a finite amount of energy, which exercise only depleted.” Golf, apparently, is an exception, being a sedate enough sport to do no harm.

It is true that overexertion during extreme endurance training and athletic events can put midlifers at a slightly greater risk of developing issues such as an irregular heartbeat, aka atrial fibrillation, as was outlined in the British Journal of Cardiology this year. Yet endurance runners don’t die younger than everyone else — indeed, the opposite may be true: a 2023 study of 4,500 people by a team at Brigham Young University in the US found that those who ran for at least 75 minutes a week had a biological age about 12 years younger than those who ran for less than 10 minutes a week or not at all.

For most people, exercise lowers the chance of developing cardiac issues. And comparing the human heart to a Duracell battery overlooks the fact it is a muscle that can be strengthened through aerobic activity, the consequence of which is that the heart is likely to become more efficient and pump more blood per beat, leading to a lower resting heart rate.

Van Puyvelde was interested in how the number of heartbeats expended during exercise and the number subsequently saved by the heart’s resultant increased efficiency could be used as a metric to calculate “a heartbeat budget” — a measure of how wisely we are “spending” or “saving” our body’s most valuable commodity.

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With colleagues at the St Vincent’s Institute of Medical Research in Melbourne, he investigated the potential health implications of intense exercise training by analysing heart rate data from fitness monitors used by 109 endurance athletes and 38 healthy nonathletes in a controlled study. Predictably super-fit individuals were found to have a significantly lower resting heart rate, resulting in fewer total daily heartbeats compared with the healthy controls. Results showed that the average heart rate was 68 beats per minute for athletes and 76 beats per minute for the more sedentary group.

Over a 24-hour period this worked out at about 109,440 heartbeats in the nonathletic group compared with 97,920 heartbeats in the endurance-trained participants, representing a heartbeat “saving” of about 11,500 beats a day. “That 10 per cent difference adds up over time,” Van Puyvelde says. “It shows the fitter you are, the more metabolically efficient your body becomes.” The results, published in the Journal of the American College of Cardiology Advances, roundly dispel the myth that endurance exercise uses up your heartbeats to ill effect.

“Overusing your heart isn’t the problem; it’s not using it enough that might be an issue in the long term,” explains Tom Brownlee, an assistant professor in applied sport sciences at the University of Birmingham. Even if you’re working out intensely for an hour or two a day, the reality is that your heart beats more slowly and efficiently for the other 22 or 23 hours. “The net result is that your heart tends to beat less frequently overall in the course of your lifetime.”

Echoing Brigham Young University’s findings, recent epidemiological studies have shown that even elite endurance athletes, who were once thought to die earlier than the general population, have increased lifespans compared with the rest of us. A 2023 report by the International Longevity Centre at City University of London looked in detail at the lifespan of Commonwealth Games competitors and found that, across individual sports including track-running and swimming, male athletes gained 4.5-6.3 years of life and women lived 3.9 years longer than average. The lead author, professor Les Mayhew, noted that “the longevity of distance runners is marginally higher than [that for] those who run other distances”.

Then came a study published last year that looked at the first 200 male athletes to run a sub-four-minute mile. It showed that these elite runners typically lived about five years longer than average, which, said the researchers from Australia and the University of Alberta in Canada, “challenges the notion that extreme endurance exercise may be detrimental to longevity”.

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Even many competitors in the gruelling Tour de France appear to have enhanced longevity. Researchers at the University of Valencia compared the longevity of 834 cyclists who took part in the three-week cycling race between 1930 and 1964 and found that the age at which 50 per cent of them died was 81.5 years, compared with 73.5 years for 50 per cent of the general population.

As Van Puyvelde points out, the effort entailed in completing a single Tour de France stage can cost cyclists about 35,000 extra heartbeats, but results in improved cardiac efficiency. “What’s really happening is more of a push/pull scenario in which you do ‘spend’ more of a heartbeat budget during physical exertion, but you also ‘save’ more of them in the long term.”

Van Puyvelde says his research findings strengthen the argument for keeping tabs on your daily heartbeat. He says it could function as “a simple but all-encompassing metric of metabolism that could help to determine exercise doses” as fitness levels increase. Knowing your heartbeat budget may also help to highlight when you are stressed or tired.

“It could act as a sort of safety signal telling you when you maybe need to be a bit more active or if you need to slow down,” Brownlee says. “Your health and longevity depend not on how many times your heart beats in your lifetime, but how well you spend each heartbeat.”

It is already possible to measure our heart rate — the number of beats per minute — using a fitness tracker, Van Puyvelde says, and he “wouldn’t be surprised” if manufacturers soon have us counting heartbeats as we do steps. “The data is already there,” he says. “It’s just a matter of packaging it and then it’s an easy concept to help understand how your lifestyle impacts your heart and metabolic efficiency over time.”

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What you need to know about your heart healthYour heart will beat about 2.5 billion times during your lifetime

“Rough maths suggests an average person’s heart beats about 70 times per minute, which equates to 100,000 a day,” Brownlee says. “But your total number of heartbeats is individual to you and influenced by your lifestyle habits and how fit or stressed you are.” The precise speed of the pumping action is controlled by your heart’s electrical system, which signals how fast and hard to beat in response to physical and emotional demands.

Calculate your maximum heart rate by subtracting your age from 220

This provides a rough estimate that’s within about ten beats of reality for most people, “so good enough for general guidance”, Brownlee says. “There are newer formulas, such as 208 minus 0.7 times your age, which is a little more accurate, especially for older adults.”

You can work out at a high intensity whatever your age

“It’s perfectly safe to work up to 80-90 per cent of your maximum heart rate in midlife or later, provided you’re used to exercising at that intensity and don’t have symptoms or medical restrictions,” Brownlee says. “The heart, like any muscle, adapts to challenge and pushing into higher training zones keeps your cardiovascular system responsive and your fitness from sliding.”

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Monitor your resting rate

“There’s no single ideal resting heart rate [RHR] because genetics, medication and fitness all play a part,” Brownlee says. “Everyone is different, although there are broad patterns that hold true.” Adults under 40 typically have a RHR of 60-75 bpm, midlifers (40–60) have an RHR of 65-80 bpm, and older adults (60+) an RHR of 70-85 bpm.

“Be aware that trained people often sit well below those ranges, even in their fifties or sixties, without it being a problem,” he says. “What really matters is trends of your RHR, and if it rises by 5–10 bpm over a few weeks, it can signal fatigue, stress or illness.”

Brownlee suggests monitoring RHR first thing in the morning, before coffee or even getting out of bed, when your body is rested and least affected by temperature, caffeine or stress.

Pay attention to warning signs

For most people the benefits of regular exercise include better heart function, lower blood pressure and reduced risk of stroke and heart attack, and far outweigh the relatively small risk of issues such as atrial fibrillation. “Appropriately planned moderate to vigorous-intensity exercise is overwhelmingly protective for your heart health across all ages,” Brownlee says. “But if you are someone who has trained heavily for years doing endurance events, it’s sensible to pay attention to warning signs like palpitations or dizziness, and to balance high-intensity work with recovery.”

Your daily heartbeat tally increases with age

Your resting heart rate usually creeps up with age as fitness and powers of recovery decline. It follows that your total daily heartbeat tally also rises with age.

“From our data, which was a young and healthy cohort, we showed that daily heartbeat consumption was somewhere between 80,000 and 110,000,” Van Puyvelde says. “At an older age in more sedentary people, that would likely be closer to 120,000 beats per day.”

If you are fit and active, the spike will be much less severe. Good heart rate recovery after exercise and a stable rhythm at rest are positive signs. “At any age a healthy heart adapts,” Van Puyvelde says. “It speeds up when you move and slows when you rest.”

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How to keep tabs on your pulse

Fitness trackers don’t provide a daily heartbeat tally — yet. But Van Puyvelde says we can estimate it for ourselves by tracking heart rate with a smartwatch or heart rate monitor. “For now I keep tabs on my resting heart rate as most watches don’t display the daily average heart rate except during a certain activity,” he says. “I recalculate my heartbeat consumption during an activity and work out the total each day from that.”

Don’t get too hung up on precise numbers. “It’s more about awareness, seeing how training, stress or sleep affect your heart’s workload,” he says. “As you are more active and get more fit, you would see the daily number come down, but if you are overdoing it you would see it go up, giving an indication you need to take more rest.”

You can reduce your bpm by listening to music

In a German study conducted in 2016 at Marien Hospital Herne and in the MA building at the Medical Faculty at Ruhr University Boc, researchers found that subjects’ heart rate was lowered by listening to classical music (of the pieces selected, Mozart’s Symphony No 40 in G minor had the greatest effect).

Meanwhile, Costas Karageorghis, a professor in sport and exercise psychology and the head of Brunel University London’s Sound and Vision Innovations group, has shown many of our bodily rhythms, including our heartbeat, “lock into” music, so that we sync our stride and movement patterns with it when we run, walk or lift weights.

It may be affected by your partner

In one study at the University of Illinois, the heartbeats of couples in long-term relationships were shown to synchronise when they were in close proximity to each other.

Incidentally, a 2017 study by British researchers reporting in the journal Cortex showed that people who are more aware of their heartbeat are also more perceptive about the emotions of other people.