DIY Test for Heart Rate Variability
HRV (Heart Rate Variability) has been all the rage for the past few years. All sorts of trackers, watches, and chest straps have been made to “score” HRV. To start, none of them are very accurate. Sure, you can track and see patterns, which is helpful, but why spend all the money on a HRV-specific tracker when you can do it for free. Plus the test I’m about to tell you about also turns into treatment… so it’s a much better use of your time!
First, HRV is the measure of time between heartbeats measured in milliseconds. The more variable (or higher) this time is, the better. It sounds a little counterintuitive but a higher rate of variability between heartbeats indicates the body is more flexible and able to adapt to stress. Therefore HRV is a measure of the flexibility and capacity of your autonomic nervous system. There’s a little more physiology to it, but here’s a quick explanation: the variability in the pace of the heart beating and relaxing is a battle between our sympathetic (fight or flight) and parasympathetic (rest and digest) nervous system. The sympathetic dominant state quickens the pace and demands the heart to be consistent like a metronome (who wants an inconsistent heart when you’re being chased by a lion… nobody, we want it beating quickly and consistently); whereas parasympathetic states call for a slower, more laid back heart (think chilling on a beach watching a sunset). So, picture the all-gas, no-breaks David Goggins on one side versus the Dalai Lama on the other. Imagine these two battling it out in your body throughout the day… if David Goggins consistently wins, then you’ll be living a ramped-up lifestyle 24/7 and you’ll most likely burn out. The body will be more prone to staying in that "regular metronome state", even when you are craving calm and relaxation. If the Dalai Lama consistently wins then you may have difficulty performing at an alert, high level throughout the day. There is a 3rd option… these two powerful opposites living in harmony giving your body the option to ramp up or be calm and collected depending on the circumstances. In summary, a high HRV means you have the capacity and flexibility to be both David Goggins and the Dalai Lama.
Lauterbrunnen Valley, Switzerland - Fall 2023
Anyways! Enough of my poor analogies, back to my original purpose of showing you a quick, reproducible way to test your HRV / autonomic functional capacity.
CO2 Tolerance Test or the BOLT (Body Oxygen Level Test):
Take 4 easy breaths, ideally at a 1-breath every 5-10 seconds pace (a 3-5 second inhale, followed by a 5-8 second relaxed exhale, plus a 1-second pause before beginning to inhale). Don’t worry about counting if that throws you off; simplify it: 4 easy breaths with the exhale being longer than the inhale.
At the top of the 4th full inhale start the timer and exhale as slowly as possible. Stretch out the exhale as long as possible and then hold your breath. Stop the timer when your air runs out, or you feel the first urge to inhale***. It’s helpful to close your eyes to assist in staying relaxed.
***Don't be too competitive... this isn't a breath-holding contest. Your first breath following the breath-hold should not be a gasp. If you are gasping for air following the test then you held too long and the timer should have stopped sooner at “first urge to inhale”. In other words, your breathing rhythm should remain fairly smooth following the test.
Evaluating your score
< 20 seconds: Poor - High anxiety and stress sensitivity, poor pulmonary capacity
20-40 seconds: Average - Moderate to high stress/anxiety, breathing needs to improve
40-60 seconds: Advanced - Flexible autonomic function and healthy pulmonary system
> 60 seconds: Elite - Excellent stress control and breath control
Yes, this test is more indicative of how well a person tolerates carbon dioxide and utilizes oxygen, but this correlates strongly to the state of one's autonomic system aka “Heart Rate Variability”. A low CO2 Tolerance score leads to feeling more stressed, anxious, and not in control; whereas a score ideally above 40 seconds gets you closer and closer to the Goggins / Dalai Lama combo!
I recommend performing this test upon waking to get a feel for where your body is heading into the day. What I love most about this test is how it also serves as an intervention in breathwork. Performing the test will not only get you better at the test but also improve your HRV and overall stress tolerance.
Article I Found Interesting:
94-year-old rower debunks age-related physical decline
Peter Attia said it best…
“Exercise is a powerful intervention with no expiration date”
A good chunk of my client population is the aging adult and nothing frustrates me more than hearing “I’m too old to make progress exercising”. Most clients believe this to be true, and for many others, it’s just an excuse. There are all sorts of lab-based randomized controlled trials to prove this wrong, but these studies lack the gripping storytelling that can inspire individuals. I highly recommend you read the article linked above. It discusses how a 94-year-old gentleman in Ireland picked up rowing at age 73 after a lifetime of inactivity. He now has the metabolic and performance markers of a man half his age! His story is so inspiring and proves age-related physical decline is manageable and within your control. Oh, and by the way… 70% of his exercise is low-intensity.
Fun quote and a little neurobiology
“That which we persist in doing becomes easier for us to do – not that the nature of the thing is changed, but that our power to do is increased.”
-- Ralph Waldo Emerson
Here’s the neurobiology to back up Emerson… There’s a portion of the limbic system in our brain called the anterior cingulate cortex (ACC). It acts as an administrator in regulating attention and emotion. The ACC plays a role in motivation, decision-making, learning, error monitoring, conflict resolution, and inhibitory control. In other words… the ACC has its hands in many processes that make for a well-regulated, competent human being. What’s also super interesting is the ACC is very adaptable and grows as we push ourselves to do hard things we don’t particularly want to do. Just another example of neuroplasticity – the brain's ability to adapt and improve. But this growth isn’t always permanent. Take the challenging stimulus away and the ACC’s size can diminish. So, do hard things and get comfortable being uncomfortable!
I think Mr. Morgan from the story above would agree with the Emerson quote.
Thanks for reading!
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