What Is Heart Rate Variability & What Can It Tell You?

If you've ever taken your pulse, it might feel like your heart is beating at a steady pace. However, the time between your heartbeats is not consistent. A fluctuation between the timing of heartbeats is called heart rate variability, or HRV. Measuring HRV can provide information about your overall health.

This article discusses how to measure and interpret heart rate variability and what the measurement means.

How Is HRV Measured?

Heart rate variability is most accurately measured with an electrocardiogram (ECG or EKG)—a test that provides a graph of your heartbeat from electrodes placed on your chest, arms, and legs. These electrodes sense the electrical signals in your heart that cause it to beat.

The electrocardiogram measures various electrical signals to determine how fast your heart is beating, as well as the timing between your heartbeats. HRV is also called the R-R interval. The "R" phase of your heartbeat is the spike in the pattern on your ECG.

To get a more accurate idea of your baseline HRV, you'll need to monitor it for 24 hours. HRV is influenced by your stress levels, sleeping patterns, and changes in your emotions and activities throughout the day. Heart rate variability is typically recorded in seconds or milliseconds, depending on your measuring device.

How Do I Interpret HRV Information?

Heart rate variability is a result of the actions of your autonomic nervous system (ANS). The ANS controls your heartbeat, breathing, and digestion. Two parts of the ANS impact your heart rate—the sympathetic and parasympathetic nervous systems, which are:

• The sympathetic nervous system (SNS) is responsible for your fight-or-flight response. When you get upset or scared, you might notice that your heart rate increases (along with your breathing). This helps get blood to muscles in your arms and legs so you can respond to potential danger.
• The parasympathetic nervous system (PSNS) is sometimes called the "rest and digest" system. When this part of the ANS is activated, your heart rate will slow down. More blood is directed to your internal organs for digestion, rather than to the muscles in the rest of your body.

What Should My HRV Be?

In general, normal heart rate at rest for adults is between 60 and 100 beats per minute. The average HRV for a person with a resting heart rate of 60 beats per minute would be one second, but actual HRV values could have a broader fluctuation.

Heart rate variability is different than heart rate—there isn't a specific "normal" range that applies to everyone. One person's normal could be abnormal for you. Consistently wearing a tracking device for a few weeks can help you determine your baseline HRV measurement.

Why Does HRV Matter?

Higher HRV can be a sign that your body adapts well to changes in your environment and different levels of stress. Higher HRV measurements are also expected to occur when your heart rate is increased during physical activities like running. However, higher HRV can also be a sign of certain medical conditions, such as atrial fibrillation (AFib, an abnormal heart rhythm).

On the flip side, if you are chronically stressed or dealing with depression, your HRV might be lower. A low HRV can also point to a higher risk of cardiac issues such as heart attack, congestive heart failure (heart doesn’t pump efficiently enough), or coronary heart disease (arteries cannot deliver enough oxygen-rich blood to the heart).

Factors That Affect HRV

There are many factors that can affect a person's heart rate variability, including:

• Lifestyle factors: Stress, poor diet, being sedentary, and eating an unhealthy diet can have a negative impact on HRV. Making positive lifestyle changes in these areas can improve your HRV.
• Inflammation: HRV can be negatively affected by higher levels of inflammation in the body. Inflammation is associated with a wide variety of causes and conditions.
• Medication conditions: The presence of other medical conditions, such as anxiety, asthma, depression, heart disease, and diabetes, can affect HRV.
• Age: Normal heart rate is higher in younger children, which causes a higher HRV. As a person ages, HRV naturally declines.
• Medication: HRV can be impacted by medications that regulate your heart, such as beta-blockers.

How to Improve HRV

If you want to improve your HRV, try these tips to reduce overall stress and improve your health:

• Practice meditation
• Start a gratitude journal
• Exercise regularly
• Breathe deeply and slowly
• Get a massage
• Spend time in the sun
• Eat more whole foods
• Listen to music
• Spend time with friends and family
• Avoid smoking and excessive alcohol consumption
• Get plenty of sleep

Summary

Heart rate variability (HRV) is a measurement of the time between heartbeats. Normal HRV varies from person to person, and levels naturally decrease with age. Lower HRV is often associated with high stress levels and the presence of other medical conditions, but higher values aren't always better.

HRV is most accurately measured with an electrocardiogram, but can also be assessed with home monitors, including chest straps and smartwatches. Tracking your HRV for several weeks can help you determine your baseline.

A Word From Verywell

Heart rate variability is only one piece of data that can provide information about your overall health. While there are many at-home tools used to measure pulse, the accuracy of this measurement can only be ensured with medical testing. Talk to your healthcare provider if you have concerns about your HRV.