What Is Heart Rate Variability (HRV) and Does It Matter?

Thanks to wearable devices, you can use all sorts of metrics to keep track of your health. You can check your weight, blood pressure, the number of steps you take, heart rate and more as you go about your day.

While heart rate may not need an explanation, another number may be new to you — your heart rate variability (HRV). So, what is heart rate variability, and how does it affect your overall health?

HRV, a measure of the variation between heartbeats, affects your health in many ways — and may even be a better measurement than the more commonly known ones for fitness, stress levels and more.

First, what is HRV and what’s considered normal heart rate variability?

Even when your heartbeat feels steady, there may be a slight variation in the intervals between heartbeats.

No need to panic, as these variations between heartbeats are teeny, measured in milliseconds or one-thousandths of a second. As you can probably guess, these variations are what you’re measuring when you measure heart rate variability.

You should also know that HRV isn’t the same as arrhythmia, which is an irregular heartbeat. It’s a type of normal heartbeat, which is called “sinus rhythm.”

The time between each beat varies (there could be 0.7 seconds between two beats and 1.20 seconds between two other beats), and the individual time intervals between two heartbeats are known as RR intervals.

HRV can vary between people, which means there’s no one “average” heart rate variability.

Your heart rate varies at all times, controlled by the balance of the sympathetic and parasympathetic nervous systems. Both are part of the autonomic nervous system that regulates body systems like breathing and digestion.

The sympathetic system controls “fight-or-flight” responses and prepares your body for strenuous physical activity. During sympathetic activity like outrunning danger (or just getting regular exercise), your airways expand, digestion slows down and your heart rate speeds up.

On the other hand, the parasympathetic system regulates “rest and digest” functions. During parasympathetic activity — like when you’re recovering from that challenging workout — your heart rate decreases, and your body returns to operating at baseline.

Since HRV can be influenced by several factors — like physical health, lifestyle, mental health, environmental factors, age and genetics — each person’s normal heart rate variability can differ.

So why should you know about HRV, and what is a good heart rate variability?

Heart rate variability is one sign of overall well-being.

Specifically, a high heart rate variability can be one sign of good health. Low HRV, on the other hand, is associated with poor cardiovascular health (anything from heart disease to heart attacks and high blood pressure) as well as mental disorders.

It sounds counter-intuitive, but a high HRV means your body adapts to different situations like it should, while a low HRV can mean your body is always a bit too stressed.

One way you can use average heart rate variability is to measure stress and recovery.  By timing the milliseconds between heartbeats, you can figure out how challenging your next workout can be or if you should rest after strenuous physical activity.

Knowing whether or not you have a low heart rate variability may help improve athletic performance and help you figure out if anxiety and depression treatments are working well for you. This knowledge can also help you improve your sleep and overall quality of life, according to a small number of studies.

How do you know if you have low heart rate variability? Low HRV symptoms can include fatigue, poor sleep quality, anxiety and depression symptoms.

After all this information, you might also wonder, "Why is my HRV so low?"

You might have a low heart rate variability if you’re exposed to a lot of stressors over a long period of time. This can lead to a high resting heart rate and a low HRV.

Now that you know why this metric is important, you may want to learn how to improve heart rate variability.

To know how to increase your heart rate variability, you’ll first need to measure your HRV. The most accurate way is to use the results of an electrocardiogram (EKG), a test that creates a visual representation of your heartbeats.

You can also wear an HRV monitor, which is available on many smartwatches and wearable fitness trackers like chest straps.

One way to achieve a healthy heart rate variability is by reducing and managing stress levels.

Several studies have also shown that people with obesity and excess weight can improve their HRV through weight loss.

Changes in nutrition and adding more movement into your days could also improve HRV, as well as reduce excess weight and the chances of obesity. Even low to moderately intense exercise like walking has been shown to improve heart rate variability in some people.

Improved quantity and quality of sleep are also important for weight loss efforts and could lead to healthy heart rate variability.

There are many metrics to track your health, from heart rate and sleep to weight and how many steps you take. But heart rate variability is another important health metric to keep track of. Let’s recap what you should know.

• What is heart rate variability (HRV)? HRV is the time between heartbeats. The average heart rate variability is influenced by age, genetics, physical health, lifestyle habits, mental health and more.

• What does HRV mean? A higher HRV can be a sign of good health. It typically means better heart health and reduced risk of heart failure, other cardiovascular diseases and mental health disorders, as well as improved cognitive function.

• How can you improve HRV? Reducing stress, weight management, increased movement and better sleep are some suggestions of how to improve heart rate variability.

Certain devices like smartwatches can track your HRV. You can also discuss any concerns or questions about improving your HRV with your healthcare provider, from increased physical activity and stress reduction techniques to weight loss treatments.