These days heart rate variability (HRV) is widely used as an index of health. There is a growing amount of research and information surrounding HRV, but what is it and what can it tell us? In short, it is an excellent metric for looking at your nervous system balance and general well-being. This article introduces HRV and provides some practical tips on improving HRV, and in turn performance!
What is Heart Rate Variability?
HRV is a little more complex than the heart rate measures (i.e. heart beats per minute) provided by typical activity trackers. Where heart rate can give you an indication of your physical exertion at a given point in time, HRV digs a little deeper. This may be surprising, but our hearts do not beat at identical intervals. In reality there are small differences in the time between beats. For example, if your resting heart rate was 60 beats per minute, there may be 960 ms between two consecutive beats and then 1020 ms between the next.
These variations are perfectly normal and can help to provide a picture of your current health. Healthy irregularities between heart beats is actually desirable! For HRV, we use a snapshot of these variations to gauge your autonomic nervous system’s (ANS) status. When we compare these snapshots over an extended period, we can help determine trends.
Your Autonomic Nervous System and Recovery
Emmi from Movement Matters Physiotherapy previously wrote a post on WODconnect about breathing and recovery. If you haven’t checked it out, it gives some great background about ANS function and some practical tips for promoting recovery. For a quick run-down, our ANS is responsible for regulating many of our body’s unconscious processes. It’s comprised of two branches:
Sympathetic Nervous System – Our “fight or flight” system, activated during periods of stress, exercise, fear or during other strenuous activities.
Parasympathetic Nervous System – Out “rest and digest” system, responsible for our recovery and rest.
Our Parasympathetic Nervous System is essential to our long-term survival and helps us grow stronger, healthier and more powerful. Unfortunately, within our modern, highly stimulating environment, our “fight or flight” mode is often overly dominant, restricting our recovery and ruining the pursuit of those all-important gains!
Why should I care about my HRV?
HRV measurements can help us gauge our autonomic nervous system balance and help identify loading on our mind and body due to internal or external stressors. To better understand this, a simplified way is to consider our evolutionary response to a stressful situation. Our bodies tend to focus on short-term survival, rather than long-term health. In the past this was important for avoiding life-threatening situations, however long-term response to stressors can drastically reduce our health and performance.
If your HRV is lower than your typical baseline, in the long-term this can lead to increased disease (for example cardiovascular disease), increased injury risk, chronic inflammation, reduced immune function, and poor mental health (reduced cognitive ability, depression, anxiety). This is just the tip of surface when it comes to health risks associated with low HRV!
So how can I improve my HRV?
Our HRV can be influenced by a range of factors. How you exercise, eat, sleep and even your level of stress can all have an effect. Generally speaking, a high HRV is the sign that your heart is healthy since it has more flexibility to react to different forms of stress on the body. Alternatively, a reduced HRV is symptomatic of health problems which can affect immune function, self-regulation and psychosocial abilities.
It’s important to realise that your HRV is unique to you. This makes it challenging to compare against others. Focusing on your personal HRV and associated trends will give the best indication of your nervous system balance and general well-being. There are a number of modifiable and non-modifiable factors that play a role in our overall health and HRV. Non-modifiable factors include things such as our age, gender and genetics. For example, women tend to have a higher HRV than men, with HRV decreasing as we age for both sexes.
Of the most interest are the factors we have control over. These modifiable factors can relate to our lifestyle and environment.
Lifestyle factors:
- Sleep – The quality, quantity and timing of our sleep all play a major role. Sleep is extremely important to our recovery. Therefore, a good night of sleep will typically see your HRV increase. Most adults need 7 to 9 hours a night for the best amount of sleep.
- Physical activity – Although this creates short-term stress on our body, our adaptation to appropriately periodized load can lead to improved HRV in the long-term. Ensuring you break-up your training with enough recovery days is important to your long-term health. This doesn’t mean you have to sit on the couch watching Netflix for days on end. Incorporating active recovery into your schedule, like a walk in nature, can help with recovery and improve your HRV.
- Breathing - Breathing is a central aspect of our whole being and is one of our most vital functions. It has the ability to modify the biochemistry of the body, potentially impacting emotion, circulation, digestive function and the musculoskeletal structures involved in the process of respiration. Breathing exercises can be great for activating your parasympathetic nervous system, encouraging higher HRV and recovery.
- Stress, depression and negative emotions – These factors can all reduce your HRV. It’s understandable that some of life’s stresses are unavoidable, however the way we respond to these stressful situations is important. Work related stress is one example that can significantly affect our HRV. Finding tools to cope with life’s stresses and negative emotions can not only improve your quality of life, it can also improve your overall health and HRV. The key is finding what works for you (more on this in the next point).
- Meditation – In today’s over-stimulating and stressful world, our brain and body appreciate a pause. There is a growing amount of research to show that incorporating meditation into your daily schedule can have a positive effect on brain function and HRV.
- Medications – Some medications can affect your HRV (for example, some antidepressants). The effect of medication on HRV appears to be very individual and you should discuss this with your healthcare provider if you are concerned that your medications are impacting your overall health and HRV.
- Alcohol, tobacco and drug use – Chronic smokers and drinkers tend to have a low HRV. The good news is that studies show this effect is reversible when consumption is stopped.
Environmental factors:
Our environment can also affect our overall health status. Studies have shown that long term exposure to certain chemicals, electromagnetic fields, and vibrating tools can all decrease HRV. In addition, working time (time of day/night and duration of work), psychological charge (for example, combat situations) and long-term fatigue can all play a negative role.
Tracking HRV and summing it all up
It’s important to remember, although HRV can provide valuable information about your nervous system balance, it’s only part of the picture. To really understand what’s going on, it’s important to look at short and long-term trends in your HRV, rather than a one-off snapshot. It may also be necessary to dig a little deeper to determine what factors could be negatively affecting your health and performance.
There are a number of great tools coming onto the market to help you track HRV. If you are interested in taking your performance to the next level, I highly recommend looking at investing in some of these tools to track your HRV.
Research
Fatisson, J., Oswald, V., & Lalonde, F. (2016). Influence diagram of physiological and environmental factors affecting heart rate variability: an extended literature overview. Heart International, 11(1), heartint-5000232.
Sammito, S., & Böckelmann, I. (2016, May). Factors influencing heart rate variability. In International Cardiovascular Forum Journal (Vol. 6).
