After recently purchasing a device to track heart rate variability, I thought I would go into a little bit of detail as to why I have invested in something to keep track of it. You may have heard of the autonomic nervous system (ANS), or maybe you’ve heard of the “fight or flight” response at least. So before we look into why we keep track of heart rate variability, let’s discuss the ANS in general.


The ANS is an autoregulated system within your body that controls many of your bodies functions. There are 2 “modes” of your ANS; sympathetic and parasympathetic.

Sympathetic activity kicks in when your body is in its fight or flight mode. This can be during periods of stress, strenuous activity, or even when nervous or anxious. Your body reacts to this stimulus with an increase in heart rate, release of the stress hormone (cortisol), and a decrease in heart rate variability (to be discussed later). This is when our body generally is in a catabolic state and tissue is being broken down.

Parasympathetic activity kicks in when our body is in relaxation mode. This can be when we get home from work or the gym, during sleep, or any time we have a feeling of relaxation. This is when our heart rate decreases, our digestive system begins to work properly, and our heart rate variability increases. This is when our body generally is in an anabolic state and tissue is being repaired.

These 2 modes are constantly working to balance each other out, so when we train hard or have a stressful week of work, we need to ensure we recover properly by ensuring we relax and unwind. There has also been shown to be a significant relationship between the balance of the ANS and cardiovascular disease and mortality, just to reiterate its importance!


Heart rate variability (HRV) is a big indicator of this balance between sympathetic and parasympathetic activity, and how well rested we are. HRV is the slight difference in time between our heart beats. At first, it may sound like low heart rate variability sounds like a good thing! But it isn’t, a normal heartbeat should have a slight difference in the time between beats (50-100ms difference is fairly normal).

When we are training and/or working hard, our HRV decreases and our heart rate increases as a response to the stress on the body and mind. This is completely normal so don’t take this as a reason to not train! Our body has to go through periods of stress, this is just life. And the only way to physically improve fitness and strength is to put our body through stress and strain. However, if we put ourselves through this and do not recover properly, this can be when we either over train or become overly stressed. Being mentally stressed can be a huge influence on our HRV in particular.

This is when our parasympathetic activity comes into play. Our rest and digest mode is when we recover from that stress and our body becomes anabolic and repairs and rebuilds tissue that has been broken down, and our headspace improves and stress markers reduce. If we do not take time to unwind and recover, and eat a good amount of healthy, nutrient dense food then we do not allow our body to repair or our stress levels to decrease. So the next time we go to work or train hard, we are adding stress to already high stress levels.

This is why at GWD Performance we take our clients work and home life into account during each and every session. We do not take anything for granted and whilst some believe they need to train clients to absolute exhaustion every time, this may be counterproductive. We ask our clients questions at the start of each session such as how their week has been, how they are feeling and how they’ve slept. This then indicates to us as coaches how ready clients are to perform, and how hard we can push them. Our goal is to never overwork clients, but progressively improve their health and fitness through intuitive coaching.

The “stress bucket” diagram below is a great illustration of what we mean by all of this. The stress flowing into the bucket comes from work, strenuous exercise, poor diet, poor sleep, overworking, bad relationships, anxiety, the list goes on. If we allow this bucket to keep filling with these issues without using coping mechanisms (the tap at the bottom of the bucket) such as relaxation time, quality sleep, long walks, nutritious food, breathing exercises, meditation, great friendships and relationships, then the bucket will overflow and result in not being able to recover from exercise, become over stressed, depressed or ill.

So essentially, we can now use our knowledge of the ANS to categorise these influences on our health. The stress going into the top of the bucket is most things that trigger our sympathetic nervous system, such as work stress, poor sleep etc. and the tap allowing relief of that stress are our coping mechanisms and healthy lifestyle traits such as good nutrition and recovery from exercise, quality sleep etc., most things that trigger our parasympathetic nervous system.


As we previously discussed, there is nothing wrong with putting our body under stress or strain. For our body and mind to develop and grow, we need it. Its management of that physical strain and mental stress and coping with it that’s most important. Coping with the mental and physical sides are obviously slightly different, but here are some general recommendations for both:

  • MANAGE YOUR WORKLOAD – This is something more specific to your workplace, but extra hours rarely equate to extra productivity. Be sensible with your hours and workload, the better you recover and unwind, the more productive you will be the next day.
  • TRAIN SMART – For all of you sweating it out at the gym or on the pavements, be sensible with your training schedule. The benefits of exercise are endless, we don’t need to tell you that, but constant strenuous exercise with poor recovery can be detrimental to your health. The goal is always to improve and push a little further each time but don’t go from tortoise to hare in the space of a week. Progress at a sensible pace with a well-planned programme and your body will thank you for it.
  • EAT HEALTHY – No brainer here, but an amount of fresh, nutrient dense foods that matches your daily requirements WILL help you recover from both physical and mental strain. We could go on forever about what healthy nutrition is, so read our other blogs and social media posts if you need any help on that (or even better, come and see us!).
  • QUALITY AND QUANTITY OF SLEEP – Probably the biggest and most undervalued factor in recovery, and general health. Chronic under sleeping has been shown to affect our mental health, and also many illnesses and diseases, such as Alzheimer’s and cancer. Staying up an extra couple of hours to do some work is ironically going to make you less productive. Get a good sleep (on average 7-9 hours) and attack the next day! During sleep is when our body recovers the most, muscles repair and our brain is rested. Get your bedroom nice and cool, put away your phone and make your room as dark as possible. Tomorrow is a new day.
  • TAKE A LONG WALK AMONGST NATURE – Long walks are a great way to unwind, relax, and even recover from more strenuous exercise. At GWD Performance we always challenge our clients to do a minimum of 10k steps a day, not just to increase daily activity but also because it’s a great way to switch off from the world and de-stress. Little tip; leave the phone at home and enjoy being away from it all.
  • MEDITATION AND BREATHING TECHNIQUES – Another undervalued mechanism. Taking time out of your morning and/or evening to practice meditation or some simple breathing techniques have been shown to reduce stress significantly and also improve sleep. There are far better sources than myself to learn meditation so have a read up of it, and also learn a little about diaphragmatic breathing, I practice it multiple times throughout the day. Once you learn how to do it, give it a go when you are in bed in the evening and see if it can help to get you to sleep a little quicker.

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