Dr Elijah Behr, a cardiologist at Mayo Clinic Healthcare, on what it means when a wearable device warns you about your heart rate variability.
Wearable devices such as smart watches measure several aspects of health, and heart rate variability might well be one of those. To many people, it might come as a surprise to be informed that their heart rate variability is either high or low, as it’s not a measure that is widely understood. So, what does it mean?
“It measures the balance of nerve activity in the body and the way it relates to your heart rate and blood pressure,” explains Dr Elijah Behr, a cardiologist at Mayo Clinic Healthcare in London. Heart rate variability relates to what is known as the autonomic nervous system. It can be thought of as the balance between the effects of adrenaline in the body and the other part of the nervous system, the vagus nerve. “From beat to beat, or over periods of time, heart rate variability can be measured in different ways to try to assess this balance within the autonomic nervous system,” Dr Behr says.
What does having high or low heart rate variability mean? “In general people who have higher heart rate variability are more likely to have better cardiovascular fitness. Athletes tend to have a very high heart rate variability, for instance,” Dr Behr says. People with lower heart rate variability may be likelier to lack cardiovascular fitness or to have underlying heart disease, he explains.
So, does this mean people with high heart rate variability have nothing to worry about, and those with low heart rate variability should be concerned? Not necessarily. For people who haven’t been diagnosed with a heart condition and are otherwise healthy, heart rate variability alone isn’t information that a doctor can act upon, Dr Behr says. “Heart rate variability by itself isn’t likely to give you a good view of your likelihood of, say, heart attack or cardiac arrest or other heart rhythm problems. It doesn’t provide enough detail to say: ‘Yes, you’re at heightened risk of X.’”
Heart rate variability can be improved. “One could say to a patient that you need to exercise more, lose a bit of weight, get fitter. But these are things that would be promoted for heart health generally,” Dr Behr says. The best advice is to ignore it as a standalone measure and instead look more broadly at your health and lifestyle.
“Do use it as a way of pushing yourself towards being a bit healthier in your lifestyle. Watch your blood pressure, cholesterol, weight, exercise; if you’re worried about your heart rate variability, you should be worried about these too. They are more tangible risks that can be acted upon and that we know will have an impact on your longevity.”
