Where your resting heart rate goes, so goes your health.
That's the suggestion of a new study that found older Swedish men with a resting heart rate of 75 beats per minute had a doubled risk of an early death, even though that rate is well within the normal range of 50 to 100 beats per minute.
That increase in risk held for both death from any cause and death linked to heart disease.
What's more, every additional heart beat per minute increased a person's overall risk of early death by 3% and their risk of heart disease by 2%.
Based on these results, doctors might want to keep an eye on a person's resting heart rate, said American Heart Association expert Dr. Vincent Bufalino. A gradual rise in heart rate could mean trouble ahead for your heart health.
"You wouldn't have thought you'd have that level of impact from a change in your resting heart rate," said Bufalino, senior vice president and senior medical director of cardiology-AMG at Advocate Health Care in Naperville, Ill.
At the same time, Bufalino said, it's a "bit of a stretch" to consider resting heart rate as an independent heart health risk factor.
Rather, a rising heart rate probably is a red flag for other well-established heart risk factors, such as diabetes, high blood pressure, cigarette smoking and a family history of heart problems, he explained.
But, "if the heart rate's higher, it's going to possibly point you in a direction to be more vigilant with those folks," Bufalino said.
For this study, researchers led by Dr. Salim Bary Barywani, from Sahlgrenska Academy at the University of Gothenburg, tracked about 800 men born in 1943 and living in Sweden.
In 1993, these men filled out questionnaires on their lifestyle and health, and underwent a comprehensive medical exam that included measuring resting heart rate, the study authors said.
Resting heart rate was measured again in 2003 and 2014 for those still alive and willing to take part.
During the 21-year period, about 15% of the original group of men died before their 71st birthday, while about 30% developed cardiovascular disease, the researchers reported.
A resting heart rate of 75 or higher in 1993 was associated with a doubled risk of death or heart disease during the subsequent years, compared with a resting heart rate of 55 or lower, the findings showed.
At the same time, a stable resting heart rate between ages 50 and 60 was associated with a 44% lower risk of heart disease between ages 60 and 70, according to the report published online April 15 in the journal Open Heart.
The researchers noted that because this is an observational study, a true cause-and-effect relationship can't be established.
Dr. Prashant Vaishnava, a cardiologist at the Mount Sinai Hospital in New York City, agreed with Bufalino that resting heart rate is probably an indicator of other heart risk factors.
"It seems as if that's where attention should continue to be focused rather than on resting heart rate, which can vary due to a whole slew of reasons, frankly," Vaishnava said. "If I see a patient in that age range with a resting heart rate of 75 beats per minute, I'm not necessarily going to look at that as a risk factor, but I would continue to look at the rest of their risk factor profile."
Doctors generally tend to look for extremes when checking heart rate, Bufalino said.
"We know as your heart starts to fail, your heart rate goes up for sure," Bufalino said.
Too slow also isn't good -- a heart rate down in the 40s also can indicate that the heart's natural pacemaker might be failing, he added.
"The extremes of real slow and real fast, those are well-established markers for us to observe and intervene," Bufalino said.
Vaishnava said people should probably "take these findings with a grain of salt," given that the study involved only men and that other factors might have played a role in those who died early.
People who have an elevated resting heart rate can improve it through more aerobic exercise, Bufalino said. They also ought to talk with their doctor about managing other heart health risk factors like high blood pressure and cholesterol.