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Heart Disease

What Is Heart Rate Variability and Why Does It Matter?

Christina Palmer, MDSophie Vergnaud, MD
Written by Christina Palmer, MD | Reviewed by Sophie Vergnaud, MD
Published on May 20, 2024

Key takeaways:

  • Heart rate variability (HRV) is a measurement that can give you information about your stress levels and overall health. 

  • There are now easy ways to track this yourself.

  • Low heart rate variability is associated with many health conditions including heart disease, diabetes, and depression. 

  • Easy changes in your daily routines can improve your heart rate variability including avoiding alcohol, staying well-hydrated, and getting a good night’s sleep.

In the quest for better health and wellness, there’s a metric increasing in popularity: heart rate variability (HRV). HRV can provide more information about your health than blood pressure or pulse rate. It’s a reflection of your body’s overall stress level and health. For example, your HRV will lower with a poor night’s sleep, illness, and stress. That matters because a low HRV is associated with many health conditions including heart disease and diabetes.

So what exactly is HRV, and why should you pay attention to it?

What is heart rate variability?

HRV is the amount of time variation between each heartbeat. Yes, you read that right. A healthy heart doesn’t beat at precise intervals like a metronome. Instead, there is (and should be) some change in the time intervals between each heartbeat. This amount of variation is impossible to measure by just checking your pulse — we’re talking about fractions of seconds. 

But, this small amount of time does reflect how much stress your body is under. 

What is the link between stress and HRV?

HRV is a window into your body's stress response. HRV changes based on the balance of your sympathetic nervous system (“fight or flight”) and your parasympathetic nervous system (“rest and digest”). 

Simply put: When you’re stressed and have more sympathetic nervous system activity, you have a lower HRV. And, when you’re relaxed with more parasympathetic activity, you have a higher HRV.

Knowing your HRV can help get an objective measure of your stress level. This may help you know when to make changes. It can also allow you to monitor your stress levels over time and in response to the changes you make.

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What can heart rate variability tell you about your health?

Having a high HRV suggests your nervous system is in a healthy balance. A low HRV means a higher nervous system activation — common with higher stress levels. 

HRV can help you better understand your overall stress level. It can also give you insight into your sleep quality, your heart health, and your mental health. 

Low HRV has also been linked to an increased risk of some serious health conditions. This is likely because autonomic nervous system dysfunction plays a part in these diseases.  

Heart disease and HRV

HRV may be a useful tool to assess overall cardiovascular health. Research suggests that low HRV is associated with a higher risk of hypertension, heart disease, and heart failure

Diabetes and HRV

Diabetes can have effects on the nervous system, including the nerves that control the heart. Low HRV has been linked not only to high blood glucose and diabetes, but also to early diabetes (prediabetes).  

Gastrointestinal conditions and HRV

The nervous system and the gut are connected (this is known as the gut-brain connection). Research shows that low HRV is linked to gastrointestinal (GI) conditions, including irritable bowel syndrome (IBS) and inflammatory bowel disease (IBD). 

Mood symptoms and HRV

Research shows that a low HRV has also been linked with mental health conditions like anxiety and depression. Monitoring HRV could help in evaluating and treating mood symptoms to improve mental health outcomes. HRV biofeedback is already being used for therapy, stress management, and athletic training.

Sexual dysfunction and HRV

There are links between low HRV and sexual dysfunction, too, including erectile dysfunction and female sexual arousal disorder. Using HRV as a metric could help evaluate and treat sexual dysfunction.

What is a ‘good’ HRV?

There’s no set goal for HRV, since it’s different for everyone. It can range from below 20 milliseconds to over 100 milliseconds. The optimal HRV for you depends on several factors, including your genetics, your age, and your overall health. 

It’s helpful to know your baseline HRV. Then you can track it over time to see how it changes in response to life events and behaviors. 

How do I measure my HRV?

HRV is too small to measure without an EKG, an app, or a wearable device. The good news is that these days there are many ways to track your HRV. Some options for at-home tracking include: 

  • Fitbit: Some Fitbits like the Fitbit Inspire 3 have HRV tracking and allow you to see your HRV trends in the Fitbit app.

  • Apple Watch: The Apple Watch tracks HRV, and this data is available in the Health app 

  • Garmin: Watches like the Garmin Forerunner 255 and many other models track HRV.  

  • Oura ring: The Oura ring is a smart ring that tracks HRV throughout the day and night, and provides this data and insights through the Oura app.

  • WHOOP: WHOOP is a wearable fitness tracker that continuously monitors HRV, and provides trends and insights through the WHOOP app.

  • Polar Watch: Polar has several watches and wearables sensors that track HRV and provides this data and insights through the Polar Flow app.

  • HRV4Training app: HRV4Training is an app for HRV tracking that uses your smartphone camera. 

What causes low heart rate variability?

There are a lot of factors that can lower HRV. Some you can influence, and others you can’t. 

For one, we know that simply aging will lower HRV — especially for people over the age of 70. Certain physical stressors, like pregnancy or fevers, can also lower HRV. And medications, too, such as tricyclic antidepressants (TCAs).

But there are other causes of a low HRV that may be more within your ability to change, for example: 

HRV can change quickly as a result of lifestyle improvements. But, while HRV will fluctuate from minute to minute, your average HRV will gradually change day by day if you maintain the positive changes in your habits and environment. So, tracking HRV over time can provide helpful feedback about how your lifestyle decisions are affecting your health.

What should you do if your heart rate variability is low?

If you notice that you have low HRV, the first step is to track it over time. Try to identify what impacts it. For example, changes in your sleep, what you’re eating, how much you’re exercising, and your stress levels. Keeping a daily record of your habits, how you’re feeling, and your HRV may help you identify patterns over time. They may also help you stick with healthier lifestyle choices as you see positive benefits on your HRV.

When should you see a doctor about your heart rate variability?

You may try to review your HRV data with your medical team during a preventive visit or wellness exam. It could also be useful to bring up your HRV patterns with your care team if discussing related topics like stress, lifestyle, or sleep. They may be able to help you identify and address areas to focus to improve your health and HRV.

Additionally, it’s a good idea to see your primary care provider if you notice the following:

  • Ongoing low HRV over time that doesn’t improve with lifestyle changes

  • Symptoms like dizziness, fainting, fatigue, irregular heartbeats, gastrointestinal symptoms 

  • Health conditions like heart disease, diabetes, or mental health disorders

  • A sudden severe decrease in your HRV, especially if you have any other symptoms with this, such as chest pain or shortness of breath

How can you improve your heart rate variability?

There are some simple changes you can make to improve your HRV. But since HRV is very individualized, the key is to track your own HRV over time, and see what matters most for you and your health. 

The following are a good place to start when it comes to improving your overall health and stress levels:

The bottom line

Heart rate variability (HRV) is a measurement that gives you an understanding of your body’s level of stress. It reflects the balance of your sympathetic and parasympathetic nervous systems. Low HRV is linked to problems affecting your heart, mind, metabolism, gut — and more. 

With home trackers and wearables, you can now easily measure and track your HRV. Most importantly, you can see what is normal for you, and what happens when you make small but impactful changes in your life. Try limiting alcohol, getting a better night’s sleep, exercising, and adding in a mindfulness practice — and see for yourself how this affects your HRV and your health. 

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Why trust our experts?

Christina Palmer, MD, is a board-certified family physician with a focus on chronic care management, women’s health, and mental health. She’s the co-author of the book, “Open Heart: When Open-Heart Surgery Becomes Your Best Option”.
Sophie Vergnaud, MD, is the Senior Medical Director for GoodRx Health. A pulmonologist and hospitalist, she practiced and taught clinical medicine at hospitals in London for a decade before entering a career in health education and technology.

References

Bourdillon, N., et al. (2021). Sleep deprivation deteriorates heart rate variability and photoplethysmography. Frontiers in Neuroscience

Castro-Sepulveda, M., et al. (2014). Hydration status after exercise affect resting metabolic rate and heart rate variability. Nutricion Hospitalaria

GoodRx Health has strict sourcing policies and relies on primary sources such as medical organizations, governmental agencies, academic institutions, and peer-reviewed scientific journals. Learn more about how we ensure our content is accurate, thorough, and unbiased by reading our editorial guidelines.

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