HRV, Breath, and the Nervous System: A 3-Way Impact on Performance
How three different physiological factors come together to impact your performance.
Heart rate variability (HRV) is a popular biometric these days, and for good reason. Harvard Medical School reports that HRV is a useful metric for understanding your overall wellbeing, as it can help quantify the toll that stress, lack of sleep, and fatigue are having on the body.
This information is especially useful in sport. But to understand why, it’s helpful to know how HRV, the nervous system, and our breath are related.
What is HRV, and how does it relate to breathing and the nervous system?
HRV measures the variability in the time that occurs between heart beats. Although the heart beats at a regular interval, the amount of time from one beat to another is not actually the same.
This is due to two different, but related factors: the breath, and the nervous system.
When we breath in, we activate the sympathetic nervous system (SNS). This is the part of our nervous system that is responsible for “fight or flight” mode. As Bessel van der Kolk states, it’s the body’s “accelerator.” It prepares us for competition.
When we breath out, our parasympathetic nervous system (PNS) becomes activated. van der Kolk refers to this component of the nervous system as the body’s “brakes.” It promotes the “rest & digest response” and helps the body with restorative processes.
However, our breath also impacts our heart rate. When we breath in and the SNS becomes active, our heart rate increases; when we exhale and tap into the PNS, it decreases.
Thus, with each breath we take, we increase or decrease our heart rate. These changes in speed result in slight temporal differences between beats, which is where the name heart rate variability comes from.
How do these factors impact performance?
HRV represents a snapshot of how one’s nervous system is functioning. When there is more variability it means that the PNS and SNS are in balance. Low variability, on the other hand, may indicate heightened levels of stress and fatigue, or inadequate rest. This information is useful for performers, as it can can help them identify when they may be overtraining or under-recovering. It can be thought as how ready your body is to perform.
The ability to balance these two systems is essential for performance. The Individual Zone of Optimal Functioning (IZOF) theory is built on this concept. It posits that the optimal level of physiological arousal is dependent on 1) the demands of the task, and 2) what the individual determines is helpful for said task. Some may find that feeling calm, cool, and collected is necessary to perform. Others may prefer to feel so amped they could run through a brick wall.
In either case, to reach this optimal level of arousal requires an ability to modulate one’s PNS and SNS accordingly.
Our breath is a powerful tool that can help us do so, especially leading up to a performance.
There are hundreds of breathing patterns out there, but here are three key tips:
- Deep breaths into the diaphragm will have the biggest impact. Try putting your hands on your belly, middle fingers touching. Your fingers should separate if you are breathing through the diaphragm.
- If you using breath work to relax, focus on the exhale. Try making your exhale longer than your inhale (for example: 4 seconds in, 6 seconds out).
- Taking several deep breaths into the diaphragm can be challenging when you are physically exerting yourself. If you feel a need to calm yourself in the heat of the moment, try the physiological sigh, a technique recently popularized by Dr. Andrew Huberman. Check out this video below for a demonstration.
Bringing in all together
HRV serves as a “window” into the nervous system. High variability indicates that PNS and SNS are well balanced, while low variability may indicate the body is experiencing heightened effects of stress and fatigue, or is perhaps suffering from a lack of sleep. Thus, HRV serves as a useful “check in” for performers to understand what how prepared they are for training or competition.
The ability to balance the PNS and the SNS is equally important for performance. Achieving one’s IZOF depends on their ability to up-regulate or down-regulate these systems. The breath is one tool that people have at their disposal to help them do so.
If you’d like to explore more breathing practices, check out Breath by James Nestor. This is a phenomenal book that investigates a variety of breathing techniques, and how our breathing patterns impact health and well being.
Lastly, if you like to measure your own HRV, check out this link with a list of recommendations.
Resources
van Der Kolk, B. (2021).The body keeps score: Brain, mind, and body in the healing of trauma (S. Pratt, Narr.) [Audiobook]. Audible. https://www.
audible.com/pd/The-Body-Keeps-the-Score-Audiobook/0593412702 (Original work published 2015)
