On average, alcohol can be found in your bloodstream for roughly 6-12 hours after consumption (depending on the amount) and detected via breathalyzers or urine tests for about 24 hours. While your body usually breaks it all down within a day, we’ve found the effects of alcohol may actually linger for much longer.
Below we’ll look at how your body metabolizes alcohol, as well as factors that influence the speed at which it’s able to do so. We’ll also examine the impact drinking alcohol has on heart rate, HRV, sleep, and other physiological data tracked by WHOOP, plus how long these metrics can be negatively affected by it.
The first place alcohol goes when you drink it is into your stomach. It then enters your blood through the lining of your stomach and small intestine. Enzymes in the stomach can begin to break it down prior to hitting your bloodstream, but this varies from one person to the next. Food in your stomach may also help to absorb the alcohol and block it from moving on to the small intestine.
Most of the alcohol gets to your bloodstream through the duodenum (the beginning of your small intestine), where it is then carried to your brain and all other organs in your body. After that, the liver works to process alcohol in your blood. Although your liver is the primary organ responsible for metabolizing alcohol, small amounts of it also exit your body through your kidneys (urine), lungs (breath), and skin (sweat).
Many people falsely believe that since alcohol is a sedative it can help them sleep. Unfortunately they don’t realize that although it might technically put them to sleep faster, it drastically reduces the overall quality of their sleep.
When your body is sedated and simultaneously working hard to scrub alcohol from your system, it is unable to reach the restorative stages of sleep (REM and deep sleep). Even if you sleep for a long time following alcohol consumption, you’ll likely just get a lot of light sleep and not wake up feeling refreshed or well rested.
Here is an example of one WHOOP member’s sleeping heart rate on successive Saturday nights. The first represents a normal night’s sleep, while the second is after they had 4 drinks in the evening prior to bedtime:
You can see the dramatic difference in heart rate, with the first being significantly lower (average of 51 beats per minute compared to 64) and much more consistent. In the second example, the heart rate during the early portion of sleep is much higher as the body processes alcohol in the blood (a major stressor). Even once it begins to drop, the HR still continues to spike frequently.
Also notice that the first example includes more time asleep despite spending less time in bed–greater sleep efficiency thanks to fewer disturbances brought on by alcohol in the body.
Along with bad sleep and elevated heart rate, alcohol is extremely detrimental to your heart rate variability as well. In an analysis of WHOOP Journal data, when our members reported drinking alcohol before going to sleep (anywhere from just 1 drink to several) we found HRV decreased by an average of 7 milliseconds compared to baseline.
At the most basic level, your body is less capable of taking on strain when it’s poorly recovered. Most athletes fully understand they won’t perform at their best after a night of drinking, but alcohol can impact workouts from before you drink too. How is this possible?
You don’t actually get stronger or fitter while you’re exercising. Working out breaks down your muscles slightly, then they rebuild and repair themselves during deep sleep (when the body produces 95% of its human growth hormone). Since blood alcohol concentrations in your system inhibit deep sleep, they also prevent you from making fitness gains from your workouts that day.
Additionally, one night of alcohol consumption can have much longer-lasting effects that you might expect. In a study of collegiate athletes, we found that 74% had suppressed recovery metrics the day after reporting drinking (again with no amount specified). Surprisingly, 29% were still below baseline 2 days after consuming alcohol, and 19% after 3 days. Some even continued to be affected for 4 and 5 days.
READ MORE: The Four-Day Hangover
For the most part, it takes roughly an hour for your body to metabolize 1 drink. However, this can change due to a number of factors, in particular the size and strength of the drink. Traditionally, a 12-ounce beer, a 5-ounce glass of wine, and a 1.5-ounce shot all contain about the same amount of alcohol. But if you consume drinks that are larger or have a greater alcohol percentage, it will take your body more time to metabolize them.
Women’s bodies also usually take a bit longer to metabolize a drink than men’s do.
Beyond gender and the amount you drink, there are many other variables that determine how long it takes for your body to process alcohol. Other factors affecting alcohol metabolism include:
Drinking water can also help to lower your blood alcohol level, but it doesn’t speed up the rate at which you metabolize alcohol.