Heart Rate Variability (HRV): Everything You Need To Know About This Important Health Measurable + How To Improve It

If you’ve been hearing a lot about heart rate variability lately, you aren’t alone. This powerful, trackable metric has been all over podcasts and social media for what it can reveal about the status of your health - for better or for worse.

As a functional medicine expert, I love to geek out on anything health related, and the more information I can gain about my health and the health of my patients the better. In fact, heart rate variability - or HRV for short - is one key measurement that can reveal to us the status of our current health, our risk for disease later down the line, and overall longevity. 

But what exactly is HRV and is it really worth tracking? Whether you are a biohacker or just wanting to be the healthiest version of yourself for years to come, I believe HRV is one metric you’ll want to keep close tabs on. So read on to learn more about HRV, how you can track it for yourself, and what you can do to improve your score.

What is heart rate variability?

Heart Rate Variability - or HRV for short - refers to the variation time in between your heart beats. So instead of measuring how fast or slow your heart beats, it measures the time between each beat in order to determine how healthy your cardiovascular system is - specifically your autonomic nervous system (ANS).

Your ANS consists of two branches: The sympathetic nervous system (SNS) that is responsible for the “fight or flight” response and the parasympathetic nervous system (PNS) that activates your "rest and digest" response. HRV offers insights into the relationship between these two branches of the ANS. Ideally, you actually want to have a high HRV as that is a sign of a healthy ANS, whereas a low HRV is a sign of distress and according to multiple studies, (1) poor health and increased disease risk.

What can heart rate variability tell you about your health?

While it might seem like you would want to avoid a high HRV, it is actually a sign that you are in good health as it shows that your body adapts well to change and is under less chronic stress. A low HRV on the other hand can be a risk factor for a multitude of health problems as it shows that your body isn’t as resilient to chronic stressors.

As a functional medicine expert, HRV is a valuable tool in a person’s health case. Since our goal in functional medicine is to identify the root cause of health problems rather than just treating symptoms, HRV provides a window into your physiological response to stressors and assesses your risk for different conditions. In fact, a low HRV has been linked to a variety of problems including:

• Cardiovascular disease (2)
• Inflammatory Bowel Disease (3)
• Irritable Bowel Syndrome (3)
• Metabolic syndrome (4)

And when we consider the fact that your autonomic nervous system influences everything from your digestion to your immunity, it only makes sense that a low HRV would have a cascading effect on your overall health.

How to measure your heart rate variability

Heart rate variability changes are so small - less than a fraction of a second each - that they are undetectable unless you use a special device. While heart rate variability can be measured through various devices, it all comes down to the level of precision and convenience you are looking for. 

One of the most common ways to measure HRV is through electrocardiography (ECG or EKG) machines in a clinical setting, which involves attaching electrodes to the chest to record the electrical activity of the heart. Although this provides highly accurate HRV data it isn’t the most realistic for everyday tracking.

That’s where wearable devices, such as fitness trackers and smartwatches, come in as they offer a more accessible and convenient means of measuring HRV. These devices use photoplethysmography (PPG) or other sensors to monitor heart rate and calculate HRV. While they may be slightly less accurate compared to EKGs, they can still provide valuable insights into your daily HRV trends to help make you aware of any lifestyle-related changes.

Since there are many HRV trackers on the market, you’ll want to take into consideration these factors before purchasing:

1. Brand reputation and accuracy

Look for well-established brands that have been clinically validated, as this ensures that the measurements are trustworthy.

2. Comfort and durability

The comfort of wearing or using the monitor is essential, as it should fit easily into your daily routine for the most accurate data. You should also consider what you’ll be doing while you’re wearing your device in order to determine the level of durability you need, especially if you have an active lifestyle.

3. Cost and budget

As with anything, HRV devices can range in price with many cost-effective options that still provide accurate readings. Some are just a one-time fee for the device, whereas other require a monthly subscription, so you'll want to note which one fits best within your budget.

If you are ready to start tracking your HRV, I recommend looking into the following brands:

• WHOOP
• Oura ring
• Fitbit
• Polar

What is a good HRV number?

There is no “one-size-fits-all” ideal HRV number as it varies from person-to-person. A "good" HRV number depends on factors like your age (your HRV naturally lowers as you age), overall health, and lifestyle. The key is to establish a baseline for your HRV and monitor changes over time. A decrease in your personal baseline might indicate a potential health issue or stress, while an increase can be a sign that your health has started to improve.

With that said, it is important to note that it is also natural for your HRV to fluctuate day-to-day, especially if you are exposed to different stressors that can lower your HRV, including:

• Alcohol (5)
• Dehydration (6)
• Poor sleep (7)
• Pregnancy (8)
• Stress (9)

Therefore, don’t be alarmed if you notice some slight changes after a stressful day or a night of poor sleep. Instead, take it for what it is - valuable information on how you adjust your lifestyle habits for improved health.

How to improve your heart rate variability

Here’s the good news: improving HRV doesn’t involve any complicated steps or crazy therapies. In fact, improving your HRV is as simple as following a healthy lifestyle, as many of the same practices that promote overall health have also been shown to improve HRV numbers. For example, studies have found that regular exercise, (10) proper hydration, (11) eating a well-balanced diet, (12) getting enough sleep, and (most importantly) managing your stress levels, go hand-in-hand with good HRV scores.

The takeaway

Ultimately, heart rate variability is a fantastic tool to measure your health. By giving you valuable insight into your overall health, HRV arms you and your doctors with the information you need to tackle health problems at the source. No matter what your health goals are, understanding your HRV can help you reclaim your health for years to come.

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