What HRV Can Teach You About Recovery

If you’ve ever owned a smartwatch or wearable that tracks sleep and heart rate metrics, it’s likely you’ll have come across heart rate variability (HRV). HRV is a metric often misunderstood and undervalued in its relationship with our well-being and recovery. 

The heart has a natural rhythm that changes according to how the body is distributing energy and regulating itself. Heart rate variability is the measure of this rhythm. Put simply, it’s the constant variation (measured in milliseconds) between your heartbeats. A healthy heart doesn’t beat as regularly as a metronome, its rhythm actually changes ever so slightly with each beat.

For example, if your heart beats 60 times in a minute, this won’t be 1 beat per second. There may be 0.8 seconds between two beats and 1.15 seconds between the next two. Generally speaking, the greater this variability is, the more ‘ready’ you are to perform at a high level!

LET’S TOUCH ON SOME OF THE SCIENCE

Heart rate variability is mediated by the balancing act between the two branches of your autonomic nervous system known as the parasympathetic (PNS) and sympathetic (SNS) nervous systems. Your autonomic nervous system (ANS) helps you respond to daily stressors and regulates some of your body’s most vital systems such as respiratory and digestion. 

Your Autonomic nervous system also heavily influences how your heart beats. The parasympathetic branch tells your heart to slow down, making room for greater variability between beats (high HRV). The sympathetic branch however, does the opposite, telling your heart to speed up, limiting space for variability (lower HRV). 

It’s important to remember however, neither the parasympathetic or sympathetic nervous systems work exclusively, they both sit on a spectrum, whereby the parasympathetic is dominant at rest and the sympathetic is dominant under stress. The body biases one or the other to achieve either a more restful and restorative state or a high stress fight or flight state.

WHY IS HRV EVEN IMPORTANT?

HRV is one of the body’s most powerful signals for gaining insight into general well-being, stress levels and recovery. 

When our HRV reading is high, generally, that means we’re recovered, well and in good shape to perform.

On the other hand, when your HRV score is low (relative to your baseline), this typically indicates you’re under-recovered, under-slept, possibly unwell and ultimately not in an optimum state to perform.

An important factor to remember when interpreting heart rate variability readings is how unique a reading is to the individual. There are many factors that heavily influence your autonomic nervous system and therefore, your HRV. These range from age, gender and fitness levels to sleep routine, illness, hormone cycle, nutrition and hydration. A low score to you, could be high for someone else. This is why it’s important you only compare the HRV score your smart watch says to your perceived personal baseline.

Generally speaking, consistent high scores above baseline indicate good well-being, general fitness and recovery. Long-term poor HRV scores below baseline could be an indication that something isn’t right, could be stress, poor sleeping habits, overtrained or unwell.

As a loose rule of thumb, it’s suggested that a score of 0-50ms is considered poor, 50-100 somewhat compromised with room for improvement and 100+ where we want to be. However, as previously mentioned, not only do some wearables score HRV slightly differently from others, many biological factors play into your overall reading. So, if you’re doing everything right, you feel great and your watch is saying you’re averaging 65 this week… don’t fret!

A quick thought on managing stress…

It’s assumed that if you’re a busy professional, worn down and highly stressed then you should focus on cutting out any major stressors and make a major shift to your life to reduce the chronic heightened state of stress. 

However, in practicality that can be relatively unrealistic. Of course, an analysis of the stressors is necessary and major lifestyle factors can be changed to help reduce stress levels, however if we’re looking through a physical wellbeing lens and focusing on habits that can be adapted to make long-lasting improvements, the focus should be on building and carving your physiology to favour a parasympathetic state, be well recovered and able to better cope with heightened stress. 

Typically this could be achieved through improved sleep quantity and quality, better nutritional choices, low intensity aerobic exercise routine, hot and cold exposure, mindfulness practices, breathing protocols and more.

Finding your balance: Heart rate variability has natural highs and lows

Many oversimplify HRV readings, basing the assumption that a higher HRV is good and a low HRV is bad. Although, in the big picture this is true, there are times that a lower HRV is necessary.

For example, during exercise we stress our bodies, so our ‘fight-or-flight’ sympathetic system should dominate during this period to help boost our heart rate and perform physically in the moment. You can expect low HRV readings during this, followed by higher readings as our body kickstarts recovery after the exercise.

During the day, our HRV is constantly varying. Simple daily tasks such as walking up the stairs, eating lunch and even getting excited about something or having social interactions will encourage fluctuations in our HRV readings. 

This is why it’s recommended to follow the trends of your HRV during sleep. During this time, our body is in a constant state over a 6+ hour period, giving us a more honest reflection of our chronic physiological state without daily tasks potentially masking our true autonomic nervous system balance. 

To find your current baseline, I recommend wearing your smart device during the day and to bed for 3-4 days so that a baseline can be established.

LONG-TERM TRENDS AND INTERPRETING PATTERNS

Due to HRV being so responsive, it’s recommended to keep an eye on both short and long term patterns.

Comparing your daily readings to your general baseline can give you insights into which daily activities positively or negatively affect your HRV. This can also provide an indication of how activities like exercise or meditation can benefit your current wellness.

How your HRV trends over a few weeks can give helpful understanding into whether you’re successfully rebounding from a stressful or tiring day, or whether you’ve recovered from an illness. Over much longer durations such as 2-3 months, taking readings can give excellent awareness into how major life changes are impacting your life, from coffee consumption and sleep habits to exercise regimes and the stress of starting a new job.

The Most Impactful Methods of Improving Your HRV If You’re Consistently Below Baseline

• Sensible and regular exercise - Following exercise your HRV will dip, followed by a rebound with effective recovery protocols in place. 

• Resistance training - Evidence shows that enhancing the testosterone:cortisol ratio can promote a more favourable environment for enhancing recovery. Improving metabolic clearance through an increase in global blood flow can also be very beneficial.

• Good hydration - Drinking adequate water is a must. A minimum of 2.5 litres each day, more if you’re training.

• Healthy diet - Consuming adequate minerals, vitamins and antioxidants play a key role in your recovery and HRV. Whether you use supplements to ensure regular consumption, that’s up to you.

• Quality sleep - Improving your sleep quality is vital. Sleep has such a major impact on all areas of our health and recovery. Sleeping in alignment with our circadian rhythm, monitoring caffeine intake, room temperature and light exposure are just a few things you can manipulate to improve sleep.

The most common reasons I see my client’s HRV balance decreasing is usually due to: long-term stress, impact of illness, disrupted/poor quality sleep, overtraining and drinking alcohol on a regular basis.

Keep in mind however, HRV can react to multiple different factors simultaneously, making it tough to pinpoint the true reasons behind your readings or trend. 

I hope this breakdown of heart rate variability has been valuable to you!  

If you have any questions or wish to discuss your personal data don’t hesitate to get in touch.