I’m always on the lookout for ways to improve overall health and fitness…

In recent years, research has started to uncover a new health indicator that can serve as a canary in a coal mine when it comes to your overall wellness: heart rate variability (HRV). 

HRV has been linked to cardiovascular health, athletic performance, and stress levels; measuring HRV over time can help you spot and address health issues even earlier.

Let’s talk more about heart rate variability—what it is, why it matters, and what you can do to improve yours.

What Is Heart Rate Variability Anyway?

This may come as a surprise, but a healthy heart is not a metronome. 

Let’s assume, for example, that you have a resting heart rate of 60 beats per minute. It seems to make intuitive sense that your heart would therefore beat exactly once every second. Except it doesn’t.

The truth is, the time in between your heartbeats is not consistent. There is a small amount of fluctuation in the timing between beats—on the order of just a few milliseconds. That means a heart beating 60 times per minute may rest for 59.95 seconds between one pair of heartbeats, only to rest 60.01 seconds in between the next.

Does it really matter if your heartbeat changes by a few milliseconds? Well, science is beginning to discover that HRV just might be able to tell us more about our overall health than you might think. 

The Science behind HRV

Your heartbeat is controlled by the autonomic nervous system (ANS); this system is also in charge of breathing and digestion. The ANS is comprised of two parts: the sympathetic nervous system (SNS) and the parasympathetic nervous system (PNS). 

The SNS is responsible for your fight-or-flight response. When you are scared or stressed, the SNS causes your heart rate and breathing to increase; it does this to ensure you get enough oxygenated blood into your major muscle groups to take action if needed. 

The PNS, on the other hand, is also known as the “rest and digest” system. It slows down your heart rate and directs blood to your internal organs to aid in digestion. 

With these two systems both influencing your heart rate, what you end up with is a constant tug-of-war match between them. Overall they are normally very evenly matched, with no clear winner. But this is actually a good thing, and it is what determines your heart rate variability. 

Factors That Affect HRV

So now we know that the SNS and PNS each play a part in determining both your overall heart rate and HRV. But what are the factors that help determine which system is stronger at any given moment?

We know that a number of factors affect HRV. Insults to one system or the other can cause that tug-of-war match to become imbalanced. These factors include:

• Lifestyle factors. Excess stress, eating a poor diet, and being sedentary can all have a negative impact on HRV.
• Inflammation. It should come as no surprise that inflammation can negatively affect HRV, just as it has adverse health effects on so many other systems in the body.
• Medical conditions. Certain conditions can affect HRV, such as anxiety, asthma, depression, and diabetes.
• Medications. Beta-blockers and other heart medicine can negatively impact HRV.

How to Measure and Interpret Your HRV

For a long time, the only way to measure your heart rate variability was with an electrocardiogram (or EKG). This method is extremely accurate, but it’s also rather cumbersome and inconvenient.

In recent years, however, products have come on the market that allow people to measure their HRV at home. Some fitness trackers come with chest straps, and now even smartwatches and apps like WHOOP can reliably measure HRV. 

If you decide to measure your HRV, there are some key things to know. First, there is no “normal” range when it comes to HRV. What’s normal for you could be abnormal for someone else, and vice versa. So rather than comparing your numbers with a family member or friend, it’s much better to monitor your data relative to your own personal trends over time.

Second, when it comes to HRV, a higher number is usually better than a lower one. Generally speaking, the higher your heart rate variability, the more fit and healthy you are likely to be. This is because, as I mentioned above, your nervous system is balanced—the SNS and PNS typically push and pull with similar strength. This is what causes the fluctuations in your heartbeat. 

When one or the other system dominates, however, it sends stronger signals to the heart, without giving the other side as much of a chance to fight back. This in turn lowers your HRV. This is normal if you’re doing something strenuous like running a 5K, for example. In that case, you want the SNS to win! But if you aren’t doing something active and your HRV is low, it likely indicates your body is working overly hard for some other reason (e.g., sickness, fatigue) and you need to take note.

Simple Steps to Improve Your HRV

The upside is HRV can actually be a leading indicator of health. That means you can use it as a data point to better understand and personalize your own health journey. It also means improving your HRV can lead to better overall health and well-being.

Thankfully, there are many ways to work on improving your HRV. Here are five to get you started:

• Exercise intelligently. Specifically, it’s important not to overdo it when it comes to exercise or training programs. Pushing hard for too many days without adequate rest can lead to fatigue, which can lower HRV.
• Stay hydrated. Your body needs adequate water for your blood to circulate throughout your body. Without sufficient hydration, your heart has to work harder to pump the more-viscous blood to where your body needs it. Drinking one ounce of water per pound of body weight is a good goal to shoot for to maintain adequate hydration levels.
• Eat healthy and avoid alcohol. Poor diet and excess alcohol can negatively affect HRV because these practices increase inflammation in the body, which of course can lead to a whole host of health-related issues.
• Get good sleep. Sleep deprivation can wreak havoc on your body, including your HRV, which can go down due to tiredness or exhaustion. Practice good sleep hygiene habits like going to bed and getting up at the same times every day and limiting screen time at night.
• Focus on mental health. Your mental health is a vital aspect of HRV. Learning to effectively manage stress, anxiety, and even depression can make a big difference in your HRV and overall health, so take the time to prioritize mental health (and reach out for help if you need to).

We truly live in an exciting time health- and technology-wise. We can make use of unobtrusive wearables to measure and monitor key health indicators in ways that scientists and doctors could have only dreamed of in the past. I am excited about where science and technology will take us next! In the meantime, if you’re ready to take the next step in your health journey, consider learning more about—and even tracking—your heart rate variability. It could be the key to taking your wellness to the next level.

Want a personalized game plan to improve your HRV and overall health?

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