When a ‘Normal’ Resting Heart Rate Might Actually Be Signaling Trouble

Paying attention to your normal may be more helpful, new research suggests.

You might regularly check your heart rate when you’re on a run or working out, but new research suggests you may want to keep track of your resting heart rate, too: An increase in your normal beats per minute may be signaling something’s amiss, according to new research out of Sweden.

In the study, the researchers wanted to discover whether a resting heart rate at the higher end of the normal range—that’s 60 to 100 beats per minute—affected long-term heart health or the risk of early death.

To study this, they randomly selected a group of about 800 Swedish men born in 1943, and had them report on lifestyle, family history of cardiovascular disease, and stress levels. They were also given a medical exam that included resting heart rate, or the number of heart beats per minute when the body is at rest. This number can change with age, cardiovascular disease, smoking, obesity, medication usage, and even body position. (Athletes like runners often have resting heart rates in the lower end of the normal range, or slightly below it, since cardiovascular fitness makes your rate drop.)

Researchers measured the men’s levels again 10 years later, and then again with a final exam 11 years after that. Of those still alive, about 500 were willing to continue participation—just over 150 opted out.

They found that a resting heart rate of 75 or greater—still within the normal range—at baseline was associated with about a doubled higher risk of death from any cause, as well as incidence of cardiovascular disease and coronary heart disease, as compared to those with heart rates of 55 or below.

But change in resting heart rate mattered, too: People whose resting heart rates remained stable throughout the study had a 44 percent lower risk of heart disease than those whose heart rates increased during that time. What’s more, every additional beat increase in resting heart rate was associated with a 3 percent higher risk of death during the course of the study.

“The takeaway message here is that the resting heart rate in middle-aged men can have an impact on survival,” study coauthor Salim Bary Barywani, Ph.D.(c) student at the University of Gothenburg, told Runner’s World.

This may be because an increase in resting heart rate may be a warning sign of a cardiovascular change, like higher blood pressure or early heart disease. Other reasons a resting heart rate may trend upward include a poor reaction to medication, elevated thyroid hormone levels, anemia, or an underlying infection.

What about if your resting heart rate is on the lower end and then suddenly surges upward, but still stays within that normal range? See a doctor anyway, Barywani said. In other words, if your version of normal is nice and low, that sudden change in trending should prompt a doctor’s visit, even if your new resting heart rate is still well within normal.

“That’s a worrying signal, even if you only go up by 10 beats per minute,” he said. “I would get that checked, especially if that increase tends to persist.”

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