By Marnie Kunz, NASM-certified trainer, USATF- RRCA-certified run coach

If you’re wondering what is heart rate variability, this post will break it down and also offer insight into how you can use heart rate variability (HRV) in your training. As a running coach who enjoys using fitness tech, I have found heart rate variability can be a helpful way to measure fitness level, stress, and progress in training. It’s becoming increasingly popular to measure resilience and general fitness and wellness.

What Is Heart Rate Variability?

So what is heart rate variability exactly? Heart rate variability is a measure of the variation in time between beats of your heart. HRV is controlled by your autonomic nervous system (ANS), which regulates heart rate, blood pressure, digestion, and breathing. The autonomic nervous system is part of the peripheral nervous system that controls involuntary functions of your body like heart rate, blood pressure, respiration, digestion, and arousal. The ANS has two branches:

Sympathetic nervous system: This branch is responsible for the “fight-or-flight” response. It increases heart rate and blood pressure in response to stress or danger.
Parasympathetic nervous system: This branch is responsible for the “rest-and-digest” response. It slows heart rate, lowers blood pressure, and promotes relaxation.

Many factors can affect your heart rate variability, ranging from lifestyle factors like stress to mental state to fitness level. In general, a high heart rate variability shows good health. High HRV indicates a more flexible and adaptive autonomic nervous system. It suggests that your body can efficiently respond to different demands, such as stress, physical activity, and emotional changes.

In contrast, low HRV can mean that your body has reduced adaptability. A low heart rate variability may be an indicator of compromised physiological functioning and an increased risk of different health problems.

Heart rate variability is linked to many areas of health, including:

Cardiovascular health: HRV has been linked to various markers of cardiovascular health, such as blood pressure, heart rate, and arterial stiffness. A higher HRV decreases your risk of heart problems and high blood pressure. Low HRV, on the other hand, has been associated with an increased risk of cardiovascular disease, such as heart attack, stroke, and sudden cardiac death. Conditions like diabetes may also lead to a lower HRV. A lower HRV indicates a less adaptable heart rate, potentially making the heart more susceptible to arrhythmias (irregular heartbeats) - a complication associated with coronary heart disease.
Stress and mental health: Heart rate variability can be used as a measure of stress and mental health. Low HRV has been linked to increased levels of stress, anxiety, and depression. High HRV demonstrates better emotional regulation and resilience. Heart rate variability is also one of the measures used to determine the Body Battery level on Garmin devices. (Learn more in our Garmin Body Battery article).
Athletic performance: Heart rate variability can be used as a tool to measure and improve your athletic performance. High HRV usually means you’ll have better recovery from exercise, while low HRV has been linked to an increased risk of overtraining, injury, and fatigue.
Aging and lifespan: Heart rate variability declines with age. Low HRV has been associated with increased mortality risk in older adults.

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How to Measure Heart Rate Variability

If you want to find your heart rate variability, you can get the most accurate reading at your doctor’s office with an electrocardiogram (EKG). The intervals between R-waves, which represent the electrical activity associated with the contraction of the heart's main pumping chambers (ventricles), are analyzed to determine HRV.

Wearable fitness devices offer a more convenient alternative to going to the doctor but may not be as accurate at measuring heartbeats. A heart rate chest strap is a popular option for measuring HRV and these devices are generally more accurate than smartwatches or fitness trackers without chest straps.

Heart Rate Variability and Fitness

Regular exercise is one of the most effective ways to improve your heart rate variability and overall health. According to researchers, HRV can also help you adjust your training to improve recovery times and adjust your program to your fitness goals. Training places stress on your body that helps your body adapt and improve during recovery times.

Monitoring your HRV metrics allows you to see when your body is recovered and under low stress - ready for intense training, and when you’re still recovering from workouts and need to modify your workouts.

Daily HRV measurements can show you what your normal baseline is so you can adapt your training based on your HRV levels. You can tackle hard workouts such as speed workouts and long runs during training if your body has fully recovered from your last workouts and is unstressed. This will help reduce your risk of running injuries.

On the other hand, if your HRV is a lot lower than your baseline or shows signs of decreased variability, this means your body is not fully recovered from your last workouts. In this case, you can do lighter or modified training sessions to allow for better recovery.

If you need a customized training plan to help you reach higher fitness levels or crush your next race, check out the Runstreet Training Center.

What Is a Good Heart Rate Variability for My Age?

So now that you’re no longer wondering what is heart rate variability, you can see how your HRV measures up. HRV can vary based on age and health conditions so the best resource is to ask your doctor what range is best for you.

Here are some general heart rate variability guidelines based on age:

For teens and people in their 20s, HRV averages between 55 and 105 milliseconds.
There may be a slight difference in HRV based on gender, with males having a slightly higher HRV than females. Both genders experience lower HRV as they age, and the gender gap tends to close with age.
Older adults have lower heart rate variability numbers. In general, people aged 60 years and older have lower heart rate variability, averaging between 25 to 45 milliseconds.
Athletes across all ages have the highest heart rate variability, and people in their 50s and 60s who are masters athletes may have similar heart rate variability numbers to people in their 20s.

FAQs

What is a normal heart rate variability?
In healthy adults, average heart rate variability is 42 milliseconds, according to WebMD.
How to raise HRV?
A well-rounded fitness program can help your heart rate variability and overall health. Doing regular cardio exercise such as walking or running, paired with a nutritious eating plan can improve your HRV. Getting enough sleep and practicing stress reduction can also help.

Measuring Health

Heart rate variability is just one number that can help you monitor your heart rhythm, training, and health. Other ways to measure your wellness include heart rate, blood pressure, daily step count, Garmin Body Battery, and VO2 max. For runners, VO2 max is a popular way to determine your cardiovascular fitness level and estimate how well your body will respond to training.

If you have health conditions or concerns, talk to your doctor about your stats and see what tools are best for you to measure your health.

Have you tried using heart rate variability in your training? Comment below or tag @Runstreet on Instagram to share your training and get cheered on. Happy running to you! 😊

Marnie Kunz is a NASM-certified personal trainer and USATF- and RRCA-certified running coach based in Brooklyn, NY. Marnie likes helping people get and stay active to enjoy a better quality of life. When she’s not doing fitness things, Marnie enjoys exploring with her dog, a mischievous rescue Akita.

What Is Heart Rate Variability? And How To Use It In Training