A normal resting heart rate (RHR) can vary significantly among individuals, hinting that it’s not always between 60 and 100 beats per minute, a new study finds.
The heart is a vital organ, pumping blood and delivering the needed oxygen and nutrients throughout the body. The heart rate or pulse rate is the number of times the heart beats in a minute.
Most healthy people experience little variation in their heart rates at rest, but a team of researchers at the Giorgio Quer of the Scripps Research Translational Institute in La Jolla, California, has found that normal resting heart rates can differ between people by a staggering 70 beats per minute.
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Normal resting heart rate differs
Published in the journal PLOS ONE, the study sheds light on the difference of resting pulse rates between and people and how a doctor can assess whether the heart rate is normal or not. In some people, their heart rates may be normal at 100 beats per minute while it may be a sign of heart disease in others.
The scientists further recommend that visiting a doctor regularly is important to evaluate one’s heart health and doctors should gauge deviations in heart rate to determine one’s heart health than to compare the findings to the normal range in the general population.
Further, the researchers suggest that measuring fluctuations in the resting heart rate of a patient is better to gauge heart health. The doctor can measure the heart rate, but measures are rarely actionable unless they fluctuate and deviate markedly from a normal range.
The use of wearable monitors that assess or measure heart rates over time is crucial to determine one’s normal resting heart rate at the individual level.
The large-scale study
Vital signs measure one’s overall health status, including the blood pressure, temperature, pulse rate or heart rate, and respiratory rate. All these measures are important to determine a person’s health and status.
Resting heart rate is perhaps the most fundamental vital sign, but is also the most temperamental, which means it can change from time to time. The normal heart rate ranges between 60 and 100 beats per minute, with 70 as the normal reading in a healthy adult. However, in athletes, the reading tends to be far below that, and in pregnant women, it exceeds the maximum normal of 100 bpm.
Previously, resting heart rates more than 90 bpm and less than 65 bpm, have been tied to a higher cardiovascular risk. Doctors have long recognized that this viral has limitations, saying that it provides little information about the current health of a patient unless it drastically deviates from the expected range.
To land to their findings, the team conducted a retrospective, longitudinal cohort study involving 92,457 people from the United States between March 2016 and February 2018. The researches collected daily resting heart rate, and its link to BMI, sex, age, sleep duration, and variations over time.
They found that normal variations from person to person occur by as much as 70 bpm.
“Individuals have a daily RHR that is normal for them but can differ from another individual’s normal by as much as 70 bpm. Within individuals, RHR was much more consistent over time, with a small but significant seasonal trend, and detectable discrete and infrequent episodes outside their norms,” the team concluded in the study.
The team also observed a small seasonal trend in the RHR, with January incurring higher values, and July has lower values. Further, some people experience occasional heart rate fluctuations that differ by 10 or more beats per minute from their normal range.
Heart monitoring sensors
With the advent of smartphones and wearable sensors, doctors can monitor their patient's daily resting heart rates, providing a clear picture of their heart health.
The study sheds light on the importance of tracking a patient’s daily resting heart rate could help doctors assess a person’s heart status than a one-time check. The team also said that day-to-day changes in RHR could be the first individualized digital vital sign, thanks to wearable sensor technologies.
Quer, G., Gouda, P., Galarnyk, M., Topol, E., and Steinhubl, S. (2020). Inter- and intraindividual variability in daily resting heart rate and its associations with age, sex, sleep, BMI, and time of year: Retrospective, longitudinal cohort study of 92,457 adults. PLOS ONE. https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0227709