How Many Heartbeats Do You Have Left?

Our life is, of course, not literally measured in heartbeats—or at least not usefully so (since there are many other factors). However, there is a strong inverse correlation between resting heartrate and healthy longevity! That is to say, the slower your heart beats, the longer you’ll live.

Caveat: this is a generalization, and applies to a low resting heart rate that is the result of good cardiac health. It does not mean you should, for example, take up the use of heroin for its heartbeat-slowing effects. That will not help you to live longer!

Where’s the science?

Lest our opening claim there sound like popular wisdom rather than something backed by good science, let’s tend to that before moving on to the main thing today. There are, in fact, many papers to back up this claim, but here’s a good one:

It’s a 30-year longitudinal cohort study with 5,070 participants and baseline (as with most longitudinal studies, not everyone survived for the entire duration), and why we particularly like this one is not just its strong statistical significance, but also, because rather than simply looking at average resting heartrate and longevity, it also looked at changes in average resting heartrate and longevity, which makes the case for the link being causal much stronger.

❝In this study, we examined the association between resting heart rate and lifespan using linear regression in the Paris Prospective Study I, the Whitehall I Study, and the Framingham Heart Study. We used Cox proportional hazards regression to relate changes in heart rate over years to mortality risk.

We observed a statistically significant association between increases in resting heart rate over a 5-year period and risk of mortality in the Paris Prospective Study I (HR mortality per 10 bpm increase over time: 1.20; 95% CI: 1.13 to 1.27) and over an 8-year period in the Framingham Heart Study (HR: 1.13; 95% CI: 1.07 to 1.19 for men and HR: 1.09; 95% CI: 1.04 to 1.15 for women), after adjusting for classical risk factors and resting heart rate.

Our study shows that men and women who increase their resting heart rate over time increase their risk of mortality.❞

Read in full: Association between change in heart rate over years and life span in the Paris Prospective 1, the Whitehall 1, and Framingham studies

You may be wondering: why did we say 30 years, if the abstract is citing 5 years and 8 years?

And the answer is: it has to do with the statistical modeling used; the participants were followed for up to 30 years, but the statistical analysis allows us to look at what difference a change in resting heartrate makes over the course of 5 or 8 years, which is more illustrative for most people than “this is what will probably happen when you are [your age plus another 30 years]” statements. Indeed, the very fact that we can see a statistically significant change in mortality risk in just 5 years, makes it clear how big that risk is.

And how big is the risk? Translating the hazard ratios into percentages, we’re looking at, per 10 bpm increase over time, a 20% increase in mortality risk in the 5-year period per the Paris Prospective Study, or a 10%-ish increase in mortality risk in the 8-year period per the Framingham Heart Study. As for why the 5-year period has a bigger risk than the 8-year period, it’s likely down to a slightly different methodology and what other risk factors were controlled for.

One final note: about that “…and resting heart rate”, lest that seem confusing, we will mention that this too was controlled for because the primary input variable being looked at was the change in resting heartrate, not the resting heartrate itself.

In summary: if your resting heartrate increases, so does your mortality risk, at a rate of 10–20% over 5–8 years, for every 10 bpm increase (in other words: that stacks!).

So, what’s this about how many heartbeats we have left?

Based on the above, we can infer that since a change in heartrate is associated with an inverse change in longevity, the total number of heartbeats may often not change much, it’s just that the shorter-lived people squoze more heartbeats into less time.

With that in mind, a “common sense” logic tells us that we should conserve our heartbeats in order to live longer. This is somewhat consistent with the ideas behind some meditative practices.

However, while in a sense that’s not wrong (and such meditative practices can indeed help extend healthy lifespan), this presents an apparent paradox:

Should we avoid exercise, because it accelerates our heartrate while we are exercising?

And the robust answer is no, as some recent science by Dr. Kristel Janssens et al. shows clearly.

How it works: while exercise indeed speeds up the heartrate while exercising, it also lowers one’s resting heartrate by a sufficient amount (per metabolic equivalent of task minutes), that when all’s said and done, the hearts of those who regularly exercise beat fewer times per day than those who do not regularly exercise—and the difference isn’t small:

❝Athletes had an average heart rate of 68 beats per minute (bpm), while non-athletes had 76bpm. That translates to a total of 97,920 beats per day for athletes and 109,440 beats per day for non-athletes – around 10 percent less.❞

Note: that’s average heartrate, not average resting heartrate*. So it’s still counting all the heartbeats that happened during exercise, too. The athletes’ hearts were simply beating slowly enough the rest of the time to more than compensate.

*This is also worth bearing in mind because 68 bpm would be an astonishingly high resting heartrate for a very fit person.

Read the paper in full, here: Balancing Exercise Benefits Against Heartbeat Consumption in Elite Cyclists

Want to do more for your heart?

Check out:

How To Improve Your Heart Rate Variability

…for another thing to bear in mind (and helpfully, it’ll usually lower your resting heartrate, too).

Enjoy!