Could human lives be prolonged by slowing down our hearts? Prompted by the observation that mammals with higher heart rates live shorter lives than those with slower heart rates, this is the question being asked by Dr. Herbert J. Levine, an eminent cardiologist and professor emeritus at the Tufts University School of Medicine, did so in his 1997 paper, “Rest Heart Rate and Life Expectancy.”
To this day, your question has not been fully answered. But several recent studies have found important links between slower hearts and longer lives, raising resting heart rate to the level of an important indicator of health.
With the growing popularity of smartwatches and other tracking devices, people are more aware than ever of their own resting heart rate, a measurement defined by the number of heartbeats per minute at rest, such as when sitting or lying down. more than two hours after exercise. But how exactly to interpret this number and what to do with this information may not be so clear.
To further complicate matters, resting heart rate can vary widely from person to person, up to 70 beats per minute, according to a new study that analyzed the largest set of resting heart rate data ever collected.
What Is Known
The most established fact about resting heart rate is that it is inversely associated with a person’s fitness level. In other words: the fitter you are, the lower your resting heart rate will be (elite athletes, for example, tend to have notoriously low heart rates).
This is because as you exercise, your heart muscle gets stronger and requires fewer beats to pump blood.
In trying to figure out why people with lower resting heart rates seem to live longer, the researchers assumed there was no direct causal association. The leading assumption among scientists was that people with slower heartbeats were fitter and that fitness made them live longer.
“In general, when we talk about resting heart rate, there’s good evidence that lower is better.”
This assumption was tested by a study led by Dr. Magnus T. Jensen, head of the cardiology department at Amager & Hvidovre University Hospital in Copenhagen. His team analyzed data from nearly 2,800 middle-aged men followed for 16 years in Copenhagen. “Each individual had a VO2 max assessment, which is a measure of fitness level,” says Jensen.
These data allowed us to conclude that there was indeed a direct association, regardless of physical condition, between having a lower heart rate and a lower risk of mortality.
“In general, when we talk about resting heart rate, there’s very good evidence that lower is better,” says Barry A. Franklin, Ph.D., director of preventive cardiology and cardiac rehabilitation at Beaumont Health.
So what is considered a “normal” range for a resting heart rate?
According to the American Heart Association, a normal resting heart rate is between 60 and 100 beats per minute. Most experts agree with this statement, although it is not an absolute consensus, particularly at the high end.
“I respectfully disagree with calling 95 or 100 beats per minute normal,” says Franklin, adding that this range may already be related to shorter life expectancy.
This week’s full Scripps Research study, published in PLOS, showed that what’s considered “normal” for one person may be abnormal for another. The subjects’ average resting heart rates were as low as 40 and as high as 110 beats per minute.
The researchers collected data from wearable devices used by more than 92,000 people for an average of 320 days.
The study also highlighted that a person’s resting heart rate is fairly constant over time, and therefore deviations from the typical rate can be an important sign that something is wrong. “Resting heart rate variability can provide additional information not only about cardiovascular health, but also about pulmonary status, infectious disease screening, reproductive health, and possibly more,” says Giorgio Quer, first author of the study.
One of the limitations of the research is that it only tracked the participant’s “normal” heart rates, without looking at their actual health. We don’t have information about people’s health status, so we can’t say that “normal” also means healthy, says Quer.
When And How To Check Your Resting Heart Rate
There are things you can do to slow down to a healthier pace. One of the most important is to exercise regularly. “Even a brisk walking program can lower your resting heart rate by 10 to 12 beats per minute,” says Franklin.
If your resting heart rate is consistently above 100 beats per minute, with or without symptoms, you should be evaluated by a doctor.
While there are medications such as beta-blockers that can lower your resting heart rate, healthy people with a high resting heart rate but no real symptoms like shortness of breath or chest pain should not take them unless directed to do so by their healthcare provider.
“We don’t know if interfering with the heart rate with medication would prolong these people’s lives. But we have an impressive amount of data to show that lifestyle interventions — weight loss, increased fitness, lower blood pressure — are associated with lower heart rate and increased longevity,” says Jensen.