Health & Wellbeing
July 22, 2021 David Roche
A few months ago on our podcast, my co-host (what other cultures call a “wife”), Megan, mentioned how she started using a WHOOP heart-rate-tracking strap because of the Journal feature. The Journal lets users log life events, tracking how the body responds over time. Megan was interested in tracking one category of activities in particular. But I’ll let you listen to the podcast to find out because this article is rated PG (may contain graphic podcast promotion).
WHOOP heard the episode and eventually signed on as a formal sponsor (promo code “SWAP” for 15% off! Selling out never felt so life-affirming!). Many of our athletes got WHOOP straps, letting us track recovery patterns over time. Some training logs became unofficial Journals, with athletes reporting added data each day. And something jumped out pretty quickly. Those unexplained drops in recovery that would occasionally pop up?
Often, it was the day after an athlete drank alcohol.
We weren’t just seeing spurious patterns. An article by WHOOP states: “of all the behaviors available to record in the WHOOP Journal, drinking alcohol is the one with the single greatest negative impact on next-day recovery.” They even recorded a podcast on elite performers sharing stories of alcohol’s impact on their bodies.
Back in 2019, I wrote an article on the uncertain, individual-specific science of alcohol and athletic performance. One of the big uncertainties was related to how alcohol consumption may affect longer-term athletic trajectories based on changes to recovery and adaptation. That article reviewed some possible impacts to sleep, the immune system, endocrine system, and metabolic processes, with no satisfying conclusion. These heart-rate-tracking apps could theoretically integrate many of the uncertain variables into a global recovery analysis. What might that heart-rate analysis add to the discussion? Let’s dig into some of the science.
RELATED: A Nutritionist Shares What a Month of No Alcohol Did to His Body
WHOOP, Oura Ring, and other tracking tools often look at similar metrics. While wrist-based straps are less accurate than chest straps at measuring heart rate during intense running, they are reliable at rest. Resting heart rate provides insight into recovery status because it increases in periods of higher stress. That’s the horse-and-buggy, old-school data. HRV is the new hotness.
HRV measures the gap between heartbeats. As stated by a 2017 article in the Frontiers in Public Health journal, “a healthy heart is not a metronome.” The autonomic nervous system controls involuntary behaviors, like heartbeats or our unquenchable attraction to Timothée Chalamet. The parasympathetic branch of the autonomic nervous system responds to information from internal organs (“rest and digest”). The sympathetic branch responds to stress (“fight or flight”). When the nervous system is overloaded, HRV goes down as the heart essentially goes on autopilot, less receptive to nervous system signals.
A 2018 review article in the journal Psychiatry Investigations found that HRV correlates with stress, validating its use as one data point to inform stress management practices. There are tons of cool studies of how it can be used in practice (though the jury is still out on its universal effectiveness for athletes). For example, a 2018 study in the European Journal of Applied Physiology monitored the HRV of 24 elite skiers in a high-altitude training camp. In the experimental group, if HRV dropped too much (30%+) or too long (multiple days) relative to an individual baseline, athletes reduced training; if it increased or stayed the same, they would increase training. Training using shifts in HRV as a general guideline led to fitness increases, along with improved HRV.
While HRV is just one data point to inform training, recovery, and adaptation, it provides helpful clues into what stress we are handling, and what stress we aren’t. Hard training days can reduce HRV for some athletes. For example, I have a moderately low baseline of 70 (I don’t think I’ve remembered to breathe while writing the last 2 paragraphs, so it makes sense). The first time I did a long bike with Megan this season, it dropped to 51, around the 30% threshold in the 2018 study. Normal life stress also reduces HRV. My lowest reading yet was 41, the day after a short recovery jog, but when I heard tough news for a loved one. Care Bears wish they could care as hard as I do. Care swag.
And alcohol works similarly for my body. For me, it’s approximately a hard workout, even in relatively small quantities. Megan responded similarly. So did some athletes on the team. Is it signal, or is it noise? Confounding variables that make alcohol a passenger on the stress train (i.e. maybe people drink in more stressful situations), or is alcohol a stress conductor?
Fitnessaware 