Heart rate variability, or HRV, is the difference in the length of time between heartbeats.
If youve evertaken your pulse, it might feel like your heart is beating at a steady pace.
However, the time between your heartbeats is not consistent.
Illustration by Jessica Olah for Verywell Health
HRV is that fluctuation in the timing of heartbeats.
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.
Illustration by Jessica Olah for Verywell Health
What Is Heart Rate?
Heart rate is the speed of your heartbeats.
Count the number of beats in 60 seconds to determine your heart rate.
What Is HRV?
Heart rate variability results from the actions of yourautonomic nervous system(ANS).
The ANS controls your heartbeat, breathing, and digestion.
Heart rate variability is most accurately measured with anelectrocardiogram(ECG or EKG).
This test 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 is a recording of the electrical activity of your heart.
Heart rate variability is typically recorded in seconds or milliseconds, depending on your measuring rig.
Measuring HRV at Home
This is a bit more challenging, but technology is progressing.
Chest straps that use electrodes can be worn to monitor your HRV.
This technology is also being incorporated into smartwatches and apps that go along with them.
What Should My HRV Be?
There isnt a specific normal range that applies to everyone.
One persons normal could be abnormal for you.
Consistently wearing a tracking rig for a few weeks can help you determine your baseline HRV measurement.
Why Does HRV Matter?
Higher HRV can signify that your body adapts well to changes in your environment and stress levels.
On the flip side, your HRV might be lower if you are chronically stressed or dealing with depression.
Thats because if your body is in fight-or-flight mode, the variation between heartbeats tends to be lower.
Researchers observe that those with better cardiovascular fitness have higher HRV.
Lasting improvements in HRV can take several weeks or longer to achieve.
Summary
Heart rate variability (HRV) measures the time between heartbeats.
Normal HRV varies from person to person, and levels naturally decrease with age.
Tracking your HRV for several weeks can help you determine your baseline.
Harvard Health Publishing.Heart rate variability: How it might indicate well-being.
Hospital for Special Surgery.How the parasympathetic nervous system can lower stress.
2021;21(4):1061. doi:10.3390/s21041061
American Heart Association.Target heart rates chart.
2021;17(5):e160721189770.
doi:10.2174/1573403X16999201231203854
Shaffer F, Ginsberg JP.An overview of heart rate variability metrics and norms.Front Public Health.
2016;11(8):e0161648.
