Myth or fact

Water between drinks prevents a hangover

Short answerSort of

By GyroscopeUpdated November 14, 20265 sources

Sort of. Water during the evening had only a modest effect on the next day’s hangover, and water drunk during the hangover didn’t change it. Dehydration and a hangover happen together, but separately. After a big night, nights logged as well hydrated came with a slightly lower sleeping heart rate.

Why does everyone believe it?

The idea that a hangover is mostly dehydration is everywhere. You wake up thirsty with a dry mouth and a headache, which feels exactly like being dehydrated, so water seems like the obvious fix. The 2024 review that tested it calls this “a popular theory.”

Thinking water prevents a hangover is like thinking an umbrella stops the rain. It keeps one part of you drier, and the storm goes on.

What did the review find?

In 2024, a team of hangover researchers pulled together the evidence on hangovers, thirst and water. They describe a hangover as the mix of symptoms that starts “when blood alcohol concentration approaches zero.”

People who had worse hangovers also drank more water and felt more thirsty, which suggests the two travel together. But they behave differently. The dehydration was usually mild and short, while the hangover lasted. In survey data, water during or right after drinking had only a modest effect in preventing the next day’s hangover. And how much water people drank during the hangover wasn’t related to the hangover or the thirst getting better.

Their conclusion was that dehydration and the hangover are two consequences of drinking that happen at the same time but separately.

What did the WHOOP data show?

In a 2026 study of 20,968 WHOOP members, people could log whether they felt well hydrated. After nights with five drinks more than their usual, nights logged as hydrated came with a sleeping heart rate 0.3 beats lower and HRV 0.9 ms higher. The researchers called it a modest buffer. For scale, a night with one drink more than usual, against one less, came with a heart rate about 2.5 beats higher in the same data. WHOOP funded the study.

What does make a hangover smaller?

Less alcohol does. In a 2019 trial of 90 people who drank beer, wine or both to the same high level, how drunk they felt and whether they vomited predicted the worst hangovers. That’s why water between drinks is still a good habit. It’s a drink in your hand that isn’t alcohol, it slows your pace, and NIAAA’s binge line, 4 or more drinks for women and 5 or more for men in about two hours, is all about pace.

Nothing else has proven itself either. A 2005 review of eight randomized trials of hangover remedies found “no compelling evidence” that any of them worked.

The best case for water

“I always feel better when I drink water before bed.” You may well feel less thirsty, and there’s nothing wrong with that. The review found that dehydration after drinking is real, just mild and short. But it doesn’t explain the rest of the hangover, which didn’t get better with water.

Drink water, and drink fewer drinks. Hangovers covers what helps the next day, and Drinking with less cost to your night covers the evening.