Effects of Alcohol on the Body: Data Insights for HRV, Sleep & More

Physiological Effects of Alcohol Through the Lens of WHOOP

We all know alcohol isn’t good for you. From things like loss of coordination and concentration in the short term, to liver damage, cardiovascular disease and depression in the long term, the list of potential side effects is quite extensive. However, we’re not going to dive into all that here. Instead, we’ll break down specifically what we see in WHOOP data--how alcohol directly impacts the performance metrics we track like HRV, resting heart rate, recovery, strain and sleep.  

Effects of Alcohol on Sleep

Many people incorrectly believe that because alcohol is a sedative, it helps them sleep better. What they fail to realize is that it significantly inhibits the quality of their sleep, and not in a good way. In Episode 43 of the WHOOP Podcast, Alcohol's Effect on Sleep, Recovery and Performance, our Vice President of Data Science and Research Emily Capodilupo states:

Soon after falling asleep your body usually enters a period of deep sleep (also known as slow wave sleep, or SWS), which is the stage of sleep when it restores itself physically (more on this shortly). After that, a typical cycle includes time spent in REM sleep, which is the mentally restorative stage. But, when your body is sedated and must work to process alcohol in its system while sleeping, it is unable to reach these restorative stages and you get a lot of light sleep instead (learn more about sleep stages and cycles). In that case, even if you sleep for a long time after drinking, you will still fail to wake up feeling rested and recovered. Additionally, consuming alcohol at night often inhibits behaviors that benefit sleep, like a proper bedtime routine and going to sleep at a regular time (maintaining your circadian rhythm with sleep consistency).  

How Does Alcohol Affect Working Out?

To put it simply, your body is less capable of taking on strain when it isn’t well recovered. And while most athletes are well aware that they won’t perform to their usual standards following a night of drinking, the other side of this equation may come as a bit of a surprise--when you drink in the evening after you work out, you’ll likely fail to see any fitness gains from your exercise that day. Your body doesn’t actually get stronger or fitter while you’re working out. Strenuous exercise causes micro tears in your muscles and breaks them down. They then repair and regenerate themselves during sleep (slow-wave sleep in particular, when 95% of your human growth hormone is produced). But as discussed above, alcohol in your system prevents you from getting restorative sleep. Learn More: How Long Does Alcohol Stay in Your System and What Does it Do to It?  

Alcohol and HRV, Resting Heart Rate

Heart rate variability (HRV) and resting heart rate are two of the most useful metrics for quantifying your fitness on a daily basis. Consuming alcohol causes your HRV to drop (bad) and your resting heart to rise (also bad). With the WHOOP Journal feature, our members are given the option of noting whether or not they have any alcoholic drinks each day. From a Performance Assessment analysis representing everyone on WHOOP, when they report consuming alcohol (even just a single drink) their HRV drops by an average of 7 milliseconds, and their resting heart rate increases by an average of 3 beats per minute.  

WHOOP Recovery: How Alcohol Impacts Your Body’s Readiness to Perform

HRV and resting heart rate are two of the key components of WHOOP recovery (along with sleep and respiratory rate), a measure of how prepared your body is to perform each day. It should come as no surprise that 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. On average, WHOOP members’ recovery is 8% lower when they log consuming alcohol the day before (again, this includes everything ranging from one drink to several).

Also important to note, alcohol consumption can continue to affect your body well beyond just the next day. In fact, in a 2016 study of collegiate athletes, we found that the effects of one night of drinking can suppress WHOOP recovery for up to 4-5 days. Learn More: The Four-Day Hangover  

Benefits of Quitting Alcohol Seen in WHOOP Data

In 2019, WHOOP teamed up with Joe Rogan and friends for Sober October, and many of our members joined in to go alcohol free for the month. Across the entirety of our Sober October WHOOP team, we observed a number of improvements in the data. Comparing the 10-day averages prior to the month and at the end, we found each of the following increased:

• Sleep Duration: +6 minutes per night
• Sleep Performance: +1.28% (sleep achieved vs. sleep needed)
• Recovery: +1.58%

Beyond the members of our Sober October team, we’ve also had some of the best athletes and coaches in the world share the personal insights they’ve gained from WHOOP as to how alcohol affects their bodies. Learn More: What Happens to Your Body if You Stop Drinking Alcohol?