Individuals have their own 'normal' heart rate that may vary from others by up to 70 beats per minute: Study
Individuals might have their "own normal" pulse rate, which remains fairly consistent over time, suggests a new study. What's more, the study has recorded surprising levels of variations in resting pulse rates among people, with differences of about 70 beats per minute.
"It was exciting to observe that the resting heart rate of different individuals varies widely – what is normal for you may be unusual for someone else, " Giorgio Quer, Director, senior staff scientist, Scripps Research, tells MEA WorldWide (MEAWW).
A sudden change in a person's otherwise consistent pulse rate could indicate a health condition, say the authors who carried out the study. "It may prove to be a rich source of information not only for evaluating cardiovascular health but also lung health, reproductive health, early infectious disease detection and possibly more," Quer adds.
Healthy people have their heart rates that fall in the range of 60 and 100 bpm. A value of above 100 bpm could signal heart ailments, say experts. Instead of relying on a single measurement, the authors suggest, people could continuously monitoring their resting heartbeat rates. This could help them keep a watch over sudden changes.
Thanks to wearable sensors, people can now continuously measure their heart rates, making it possible to accurately identify an individual’s “normal” heart rate and potentially important variations in it over time.
So Quer and his team used collected data from wearables worn for over 320 days by 92,457 people from across the US and analyzed them for patterns. The researchers used the data to check for differences in resting heart rate within individuals, as well as between individuals.
The analysis showed that people showed a daily variation of resting heart rate by up to 70 beats per minute. The team factored in age, sex, body mass index (BMI), and average daily sleep duration — all of which could potentially interfere with the results. But they found that these factors accounted for less than 10% of the observed variations between people.
The team also found that heart rates differed during different seasons: people had a higher pulse rate in January than in July. This, according to Quer, could be due to physical fitness. "People may exercise less by the end of the year, and this may be reflected in a slightly higher resting heart rate," he explains.
Physically fit people tend to have a lower resting heart rate, with some having a rate as low as 30 bpm. The authors believe fitness may have something to do with the observed variations in the resting heart rate.
In the future, the team hopes to study how activity levels could influence the resting heart rate while also investigating its connection to health.
The study has been published in PLOS ONE.