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What Is Heart Rate Variability And How To Improve It

Everything we runners and athletes need to know to understand HRV, including what it is, why it's important, how to monitor it and how to improve it.

Many runners know about heart rate training and the many benefits of understanding your heart rate both from a training perspective as well as to learn more about your overall health and fitness status. But what about Heart Rate Variability?

Heart Rate Variability, or HRV, is increasingly used as a key metric not just for runners and other endurance athletes, but for anyone looking to improve their health and fitness, as we go about our everyday lives. 

Perhaps you’ve heard of it and know that it has something to do with sleep, training and stress levels, but aren’t sure how (or why) this metric can be helpful to track and monitor, and how to improve it for not just training gains but also in pursuit of improving your overall health and wellness.

It could even be something you may already be tracking on your smartwatch if you wear an Apple Watch, Garmin, Whoop, or Fitbit, for example, and it’s also gaining more recognition among recreational runners and other athletes, however, strangely it’s not particularly well-known or understood… yet.

Whether you’ve heard of HRV or not, in this post, I cover everything you need to know (particularly as a runner), to understand HRV, including what it is, why it’s important, how to monitor and how to improve it.

What is heart rate variability (HRV)?

Put simply, heart rate variability, often abbreviated to HRV, is the measure of the time gap between your heartbeats.

Now, you might be thinking, “Wait a minute, doesn’t my heart beat with a metronome-like regularity?” Well, not quite. Your heart rate varies, influenced by your autonomic nervous system, which is composed of the sympathetic and parasympathetic nervous systems.

The sympathetic nervous system speeds up your heart rate, preparing you for action. It’s your body’s “fight or flight” response.

The parasympathetic nervous system, on the other hand, slows your heart rate, helping you chill out, relax, and recover.

Now you may be thinking, “I don’t want my heart rate to vary much, right?”. 

Well, in fact, a higher HRV (i.e. a measurement with greater variation in that time period between heart beats over a given period of time), is widely considered as better than low HRV readings.

Confusing? Yes, a little bit at first but it makes sense if you also understand that a higher HRV score is associated with a healthier heart and a more responsive and adaptable nervous system.

As a runner rather than a sports or medical scientist, the key phrase that helped it make sense to me is ‘more responsive‘.

It’s all about providing an indication of how adaptable you are when dealing with stress, whether that’s mental or physical.

Why is understanding your heart rate variability important?

As runners and athletes, we are used to monitoring and tracking a variety of performance and health metrics – and if you’re reading this post you are probably already familiar with tracking your pace, cadence, speed, and heart rate with your running watch as you run.

Understanding your HRV can offer powerful insights into your body’s response to stress, both physical (like that marathon you’re training for) and emotional (like the stress of juggling work, life, and said marathon training).

High HRV is widely considered better than low HRV. A higher HRV is linked with improved cardiovascular fitness, resilience to stress, and even a greater capacity for high-intensity training.

When your HRV score is high, this indicates that your body is showing a healthy response to exercise and recovery periods.

A lower HRV, on the other hand, could be indicative of overtraining, inadequate recovery, or chronic stress.

Consistently low HRV may also hint at health conditions such as chronic heart failure or other cardiovascular diseases. So, keeping an eye on your HRV could help you pick up on health problems before they become serious too.

What is a good heart rate variability?

Your HRV differs based on a variety of factors including age, gender, fitness levels, and overall health. Each heartbeat is like a unique snowflake, varying with every beat. 

What counts as a “good” HRV varies by individual, so this isn’t something you can compare directly with someone else, even if they’re the same age and gender and have a similar fitness level to you.

Remember, comparison is the thief of joy – especially when it comes to your HRV. It’s more valuable to monitor changes in your own HRV over time, rather than comparing your numbers with others’.

Once you have taken a measurement of your baseline HRV (more on how to do that later), you can use this to focus your own efforts to improve HRV.

While regular exercise is one excellent way to improve your HRV, there are other things you can do as well, and we’ll get into more detail on that too, shortly.

What causes low heart rate variability?

A variety of factors can cause low HRV, including high levels of stress, overtraining, not getting a good night’s sleep, and certain medical conditions.

Your heart rate and HRV are a reflection of your body’s ability to respond to different demands and stimuli.

A consistently low HRV might signal an imbalance in your autonomic nervous system or excessive stress on the heart.

You may also be interested to learn that your HRV is likely to decrease when pregnant, although it should increase within a few months of giving birth.

How HRV changes with your training status

Your training intensity and volume can greatly impact your HRV.

An intensive workout may lead to a short-term drop in HRV as your body recovers.

If you’re giving yourself ample time to rest and are managing stress well, your HRV should rebound.

But if you’re constantly overdoing it, you might see a more significant decrease in your HRV, signaling that you’re overtraining and not giving your body the rest it needs.

These are all good reasons why it can be valuable for athletes to monitor changes in HRV, and pay particular attention if you notice you are recording a reduced HRV over time, as this could be an indication of anything from poor sleep quality to an overtraining trend that you need to pull back on as soon as possible to reduce the risk of it progressing.

How to monitor heart rate variability

The great thing about HRV is how easy it is to monitor.

There are many great wearables out there that will track your heart rate variability for you, including every day smartwatches to specific athlete-focused sports watches.

Most of these devices will also provide you with other valuable health, fitness and training-related insights, including heart rate monitoring, pulse ox tracking, breathing rate, sleep tracking as well as your running performance and overall fitness.

These metrics can also be used to produce other metrics. For example, many Garmin smartwatches will provide you with a stress tracking metric, which uses a combination of your HR and HRV to report on your stress levels throughout the day and as you sleep.

While here at Trail & Kale we test and review a wide range of fitness trackers and GPS sports watches, I have recently been using a Garmin Forerunner 965 as my everyday health, fitness and running watch.

This Garmin watch provides a comprehensive set of measurements that have helped me understand my running performance, as well as changes in my body based on my activity levels, sleep status and, more recently, pregnancy.

How wearables measure HRV

Monitoring your HRV has become more accessible than ever thanks to wearable technology.

Devices like smart heart rate monitors and fitness trackers can track your HRV in real-time.

While different companies and softwares may record HRV in slightly different ways, essentially what all these wearables are doing is tracking that time differential between your heart beats, and how much it varies over a given period of time. 

For example, many wearables will do this if you wear them while you are sleeping. This is a good time to track a consistent reading of your HRV because you’re at rest and not moving (much, at least), and they can take those measurements at a similar time each day with higher accuracy.

So the Garmin, Coros, Polar or Apple watch, for example, that you choose to wear overnight, will pick some five minute period(s) of time while you sleep to take your HRV recordings.

For our top recommendations when it comes to running and multi-sports GPS watches that will monitor your HRV (among many other things), head over to our GPS running watches buyer’s guide.

Wearables that may help you to improve HRV

Some watches like the Apple Watch and Garmin devices have meditation or breathing workouts which help to put you in a meditative state, effectively switching up your heart rate wave length to be longer (calmer) on the fly, and hence increasing your overall HRV for the day.

As well as those wearables that will track your HRV and overall health and fitness metrics, there are other more standalone devices available that may be used to improve your heart rate variability, at least in the short term.

These devices can help to put you and your body in a state of relaxation which can not only help you achieve a short term increase in HRV, but generally to help you relax and achieve a more peaceful state of mind during and after using them.

Two such meditative devices to consider are the Sensate and Apollo Neuro. To learn more about them, read our reviews:

You may also find other non-invasive ways to reduce stress can also help you improve your HRV. This can include things such as taking a warm, relaxing bath, having a massage or sleeping under a weighted blanket, for example.

How to increase your heart rate variability

While the wearables above may be helpful, they are more short-term tools to use at a certain point in time, rather than solutions that will help you achieve longer term improvements in HRV and your overall well-being.

Here are seven effective ways to increase heart rate variability:

1. Regular exercise

Regular exercise is one of the most effective ways to improve your HRV.

Activities that get your heart pumping, like running, swimming, or cycling, can contribute to a higher HRV over time. 

Therefore, if you’re regularly running or working out, or following a well-designed training plan that helps you keep your training moderated to avoid over-training, then you should see a relationship between your fitness levels and improved HRV.

2. Controlled breathing / breathing exercises

Controlled breathing exercises can stimulate your vagus nerve, which plays a key role in your parasympathetic nervous system.

This, in turn, can help improve your HRV. Take a few minutes each day to follow some breathing exercises like one of our favorites; the box breathing technique.

This technique is easy to try for yourself; simply breathe in over a 4 second period, hold that breath for 4 seconds, then breathe out over a 4 second period, hold with your breath expelled, and repeat the process.

Watch your heart rate decrease, and notice how calm you begin to feel – it’s quite a remarkable method of putting yourself into a calm state quickly.

To learn more about the power of breathing techniques on our health and state of mind, we recommend you go read Breathe by Paul Nestor – it’s one of our favorite books.

3. Adequate rest

Overtraining can cause a reduction in HRV, so ensuring you’re getting adequate rest and recovery time is crucial.

The quality of your sleep also impacts HRV.

Even if you’re not necessarily overdoing it in terms of your workouts and race schedule, simply being really busy with other aspects of life and not taking enough time for rest and recovery can be associated with reduced HRV.

4. Stress management

Stress can affect your HRV and overall wellbeing. Techniques like meditation, yoga, and mindfulness practices can help manage stress levels and therefore potentially increase your HRV.

This is also an area where the Apollo Neuro and Sensate devices mentioned above can really help, especially if you find yourself experiencing certain times of stress, or need help winding down after a particularly challenging or busy period of time.

5. Reduce your alcohol intake

Yep, I’m afraid that according to a study published in the American Journal of Physiology-Heart and Circulatory Physiology, more than one glass of wine adversely impacts HRV.

6. Spend time enjoying being in nature

If you’re already someone who enjoys hiking, trail running, camping or other ways to spend time in natural, green spaces, then you’ve probably already felt the effect that spending time in nature can have on your wellbeing.

‘Forest Bathing’ has been shown in various studies to have the effect of reducing stress and, related to this, improving HRV.

7. Eat more green leafy vegetables

You probably already knew that leafy greens such as some of our favorites, spinach and kale, have numerous health benefits – but did you know that including more of them in your diet can help to improve your HRV?

This fascinating study has shown that people who ate a lot of leafy greens such as spinach, kale and lettuces had higher HRV scores, so that’s another reason to incorporate more of these superfoods into your regular diet.

Essentially, increasing your HRV is all about balance between work and rest, between the sympathetic and parasympathetic nervous systems, and between all the demands we place on ourselves.

By keeping a close eye on our HRV and understanding what it can tell us, we’re better equipped to maintain that balance and ensure we’re training and living in a way that supports our best possible performance.

One of Trail & Kale's co-founders, Mom to Seb and guardian of our resident adventure dog, Kepler, Helen can be found trail running with Kepler and enjoying road runs with a jogging stroller, all while testing out the latest running gear for our readers.


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