What’s Heart Rate Variability?

Wearable technology is pretty amazing. It can tell you how well you slept and even count your steps.

These devices also give us insight into our heart rate and heart rate variability.

Heart rate is the number of times our hearts beat per minute. On average, an adult’s resting heart rate is between 60 and 100 bpm. However, these numbers can fluctuate with exercise, stress and other factors.

Heart rate variability is the measure of the milliseconds between heartbeats, including variations between times we’re at rest versus active. This number helps us determine whether we’re in a constant state of stress or if there is a significant difference between our heart’s “fight or flight” and “rest and digest” modes.

Unlike blood pressure or cholesterol levels, you want your HRV to be high. Higher variability is a sign of good cardiovascular fitness, the ability to handle stress and an estimate of how quickly you recover after physical activity. However, people with low heart rate variability are more likely to be chronically stressed, tired and have high blood pressure and heart rates.

While HRV can range from 17 to 75 milliseconds, the average is 42 milliseconds. This number can also be negatively impacted by stress, lack of sleep, alcohol, overtraining, dehydration, smoking, being overweight or hormone fluctuations such as menopause. Heart rate variability also naturally declines as we age.

Ultimately, you can use your HRV to understand your stress and habits, which can inspire you to make positive changes. Some of those could include:

• Better managing stress levels. Yoga, journaling and deep breathing are great ways to destress. In fact, a 2022 study found that practicing a slow-breathing method, such as box breathing, daily may improve HRV in as little as four weeks.
• Getting quality rest. It’s important to get seven to nine hours of consistent, restful sleep each night to protect your heart. Ways to improve your sleep quality include keeping your bedroom dark and cool (between 60° and 67° F) and going to bed and waking up at the same time every day.
• Engaging in regular exercise. You should aim for 150 minutes of moderate-intensity or 75 minutes of vigorous-intensity weekly, in addition to two days of strength training. Those workouts will also help you sleep better, reduce your risk of heart disease and improve HRV.
• Recalibrating your diet. According to a study published by the American Heart Association, people who adhere to a Mediterranean diet have an HRV up to 58% higher than those who don’t. It also helps to avoid alcohol and snacking close to bedtime.

Just keep in mind that light-based HRV sensors on wearable technology aren’t always as accurate as EKG readings or a Holter monitor (a smaller, wearable EKG). That’s because EKGs directly measure electrical signals from the heart rather than read blood waves through the skin.

And while HRV is valuable information, it’s only part of your well-being. Your doctor can help you with a more comprehensive approach to your overall health.

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