I take a slow, deep, belly inhale for five, following a little dot that’s climbing up a line graph on the screen in front of me, then breathe out for seven as the dot rolls back down. A strap around my waist measures my exhales, while a blood-pulse oximeter on my finger calculates my blood oxygen and pulse rate. Three colorful bars next to the moving dot track my stress levels in red, my parasympathetic nervous system in green, and how hard my nervous system is working in blue.
I’m exercising resonance frequency breathing, which, unlike regular breathing, uses an individualized, calibrated frequency so I can mechanically increase my heart rate variability. Why do I want to do that? Because higher HRV, relative to my own baseline, helps me activate my parasympathetic nervous system, which controls my body’s ability to relax, rest, and digest, leading to a slower heart rate, lower blood pressure, and a restored state of relaxation.
Administering the biofeedback session is Erin Ayala, PhD, a licensed psychologist, certified mental performance consultant, and the founder of Skadi Sport Psychology based in Minneapolis, Minnesota. I’m sitting underneath her tent at FeistyFest, a three-day movement and educational festival for women held in September in Breinigsville, Pennsylvania. Translation: My nervous system is feeling very happy.
I’ll be very grateful later that I audio-recorded the session, because I’m so relaxed that I’m tuning Ayala’s words out—I’m in the zone. This type of breathwork is “a straight shot to the nervous system, where it starts to hang out with your changing heart rate at the sweet spot, and that increases your HRV,” Ayala said during her HRV session earlier that weekend. Essentially, she added, resonance frequency breathing is “a strength-training session for your nervous system.” You heard right: strength-training session for your nervous system.
Several small studies have shown that resonance frequency breathing has a physiological impact on HRV and blood pressure regulation—and, in turn, can be linked to a positive effect on performance. By practicing resonance frequency breathing, you’re teaching your parasympathetic nervous system to kick in, and by its activation, you’re supporting your recovery and regulation—both very important to runners. A small 2020 study published in the Journal of Human Kinetics also found a promising improvement in 5K performance of track athletes after heart-rate-variability biofeedback training.
Your heart is not a metronome; it doesn’t have a perfectly steady pace. Heart rate variability measures the micro-fluctuations (in milliseconds) in the time intervals between adjacent beats, and it’s a good indicator of how well your nervous system balances stress and recovery. The normal HRV range for healthy adults is between 19 and 75 milliseconds, and our individual baselines vary greatly based on age, genetics, fitness level, and daily habits (the genetic part accounts for 50 to 60 percent of the difference).
Extract — continue reading at the source.
