Heart Rate Variability is an important and objective measure of physical health and fitness that is tracked by many wearable devices, including the Oura Ring, a personal favourite. Despite its value as a fitness tracking tool Heart Rate Variability is often poorly understood and under-utilised. Because Heart Rate Variability can be a very useful aid to help gauge and improve your body’s resilience, adaptability to stress and longevity, let’s have a look at what it is, what it can tell you, how you can use Heart Rate Variability (HRV) to optimise your health.
Heart Rate Variability explained
Your heart beats a certain number of times a minute: this is your heart rate. You can measure your heart rate by placing two fingers on a pulse point, like your wrist or the artery in your neck and counting the number of beats over a period of 60 seconds. Say you count 60 beats; this means you have a current heart rate of 60. While it may seem like your heart beats every second in this case, in reality it doesn’t: the time interval between individual heart beats keeps changing by milliseconds. Heart Rate Variability is the variation in these intervals between heart beats or simply put it is your heart’s rhythm, which keeps speeding up and slowing down.
What regulates Heart Rate Variability
The variability in your heart rate is regulated by the Autonomic Nervous System. This is the part of your nervous system that takes care of all your body’s involuntary biological functions: those that happen automatically without needing your conscious attention, like breathing, blood pressure regulation, digestion or the beating of your heart.
The Autonomic Nervous System has two branches: the sympathetic and the parasympathetic branch. The sympathetic branch is best known for moderating the body’s stress response, or the mechanisms involved in what is known as the “fight-or-flight” state. It increases your heart rate and gets you ready to deal with the challenge facing you. The parasympathetic branch restores the body back to a relaxed, resting state and it is responsible for decreasing the heart rate.
The two opposing signals from these two nervous system branches cause your heart to continuously accelerate and slow down and respond appropriately to changes in internal and external conditions, while maintaining optimal cardiovascular function.
Heart Rate Variability reflects this dynamic interplay and the balance between the two branches of the Autonomic Nervous System. As a general guideline, a higher Heart Rate Variability means that the two branches of the Autonomic Nervous System are well balanced and that your body is able to adapt effectively and respond appropriately to stress and changes in the environment.
Understanding your Heart Rate Variability Data
Your Heart Rate Variability (or heart’s rhythm) changes from moment to moment, depending on what is going on in your body and your environment. Moving around, engaging in a lively conversation, sitting down for a quiet meal, exercising, giving a presentation, watching a scary movie, taking a nap; these are all examples of activities that influence HRV from moment to moment. Measuring your HRV at any point during the day will therefore not tell you much about your overall autonomic nervous system balance. A more useful measure for that is an average HRV reading at night, when you are sleeping, and your body is in a steadier condition.
Wearable tracking devices such as the Oura ring establish your average baseline HRV over a period of a few weeks, and this can range anywhere between below 20 to over 200 milliseconds. Your baseline is unique to you and is influenced by your age, fitness level, gender, and genetics.
Once you have a baseline, single HRV readings compared to this baseline can provide you useful insights into the impact of previous day’s activities on your body, your quality of sleep as well as your readiness for the next day.
A nighttime HRV is which is lower than your baseline can indicate higher sympathetic nervous system activity, which is not necessarily bad but can be a sign that you need to take it slow, recover or manage stress levels. It can also be a reflection of having slept in a warmer bedroom, alcohol consumption, eating late, exercising late in the day, an oncoming illness, travel, a stressful event or a strenuous workout.
A higher-than-baseline HRV is an indication of higher parasympathetic nervous system activity, which means you recovered and slept well and are ready to challenge yourself, for example with a more active day or a more strenuous workout.
Using HRV trends to support your health optimization goals
Your HRV trend over a period of time can be useful to support your health and wellness goals. An increasing HRV trend or an HRV which bounces back quickly after a lower reading is a good sign and can let you know if diet or lifestyle changes are having a positive impact on your body. If your HRV is decreasing over time, you may want to make some changes in diet and lifestyle habits such as stress management, exercise, or sleep routine to nudge your Autonomic Nervous System into better balance.
Heart Rate Variability is a useful tool to help you gain insights into how your body is functioning, how it responds to changes and which adjustments can help improve your resilience and your overall health and wellbeing.
If you want to learn more about ways to optimise your health and performance, schedule a free Discovery Session with me here.
Be well!
