"It'll be fun," your friends said, when they convinced you to pay for a livestream Pilates class less than 12 hours after your Zoom happy hour. "You'll sweat it out," they claimed, when you woke up with a miserable hangover and questioned whether or not you should still do it. How being hungover impacts working out might be obvious in one sense — goodbye motivation, hello couch — but how it impacts you physiologically might be a bit more surprising. When fully hydrated, sweat therapy can have relaxing, muscle-soothing effects, but when dehydrated, aka hungover, engaging in sweat-inducing activities is counter-productive. According to internist Dr. Sunitha D. Posina, M.D., you simply can't sweat out a hangover, and most certainly should not try to. "Sweat is not a vehicle by which toxins leave the body. This is the liver’s job," she tells Bustle.
What Happens When You Work Out When You're Hungover
While working out can increase endorphins, which might make you feel better in the short term, Dr. Posina says, "it is your liver that is doing the heavy lifting to detoxify your system," so the only things that will actually fix your hangover is staying hydrated, eating something nourishing, and resting, so your liver can do its thing.
"Almost all the alcohol that you consume will be metabolized and absorbed mainly by the liver, but the brain, stomach, and pancreas also metabolize some of it," Dr. Posina says. But here's where the "sweat it out" rumors come into play. "The alcohol that remains, which is between 2 and 10%, is discharged from the body by sweating, urinating, vomiting, or bowel movement." So when you sweat, you're not sweating out the wine or tequila that you drank the night before — even if it smells like it. Instead, you're sweating out byproducts of the alcohol which is being processed in your system. So what's coming out of your pores is not healing your hangover, it's just evidence that your body is dealing with it internally.
"Hangovers really come down to dehydration, so sweating or making yourself sweat with physical activity or layers of clothes is not going to help you get over the effects of the alcohol," Dr. Posina says, adding that you're actually better off skipping the workout and amping up your water intake instead. This advice goes for saunas, too.
Is Working Out With A Hangover Dangerous?
It depends on how dehydrated you are. But if you have an obvious hangover, an intense cardio session will likely make you more dehydrated and feel worse. "This means your fatigue, your headache, your stomach issues can all be compounded," Dr. Posina says. When you're already in a dehydrated state, doing anything to exacerbate that can become dangerous.
According to trainer and nurse Kristi Nickless, R.N., "Exercising while being severely dehydrated can cause an increase in heart rate (tachycardia) which can impair blood flow to the rest of the body, resulting in mental and muscular fatigue.“
Dr. Posina also points out that when you're hungover, no matter how comfortable you are with your workout routine, you are physically not in peak condition and are more likely to make mistakes. "The lack of coordination and focus in your workout when hungover can lead to an injury or strain which can range in severity."
What To Do Instead Of Working Out When You're Hungover
After you chug a Nalgene full of water, a gentle walk or light yoga flow that doesn't require a lot of core wor,k can help to increase circulation, relax the body, and release endorphins without jeopardizing too much sweat or worsening effects. But anything that's going to jack your heart rate up, or make you break a serious sweat, is going to do more harm than help. Though it might not feel productive, sitting on the couch or taking a slow stroll while pounding water all day is going to be far more supportive for your body in this state. So don't feel bad about canceling that 7 a.m. class. It's actually the healthiest choice.
Dr. Sunitha D. Posina MD, a board-certified physician of Internal Medicine in Stony Brook, New York.
Kristi Nickless, R.N., nurse and trainer at SLT Miami.