Conventional wisdom has it that a big glass of water after a night of drinking can stave off the worst effects of a hangover the next day. Now science has come riding in with the news that, while it’s not a bad idea, it isn’t the curative we’ve been led to believe.
What it comes down to, according to new research published in the aptly named journal Alcohol, is that dehydration and the hangover “are two co-occurring but independent consequences of alcohol consumption.” And while drinking water may alleviate the first condition, it’s not going to do much about the second.
The research paper, “Alcohol hangover versus dehydration revisited: The effect of drinking water to prevent or alleviate the alcohol hangover,” was written by a team led by Marlou Mackus, a PhD candidate in the pharmacology division of Utrecht University in the Netherlands.
They analyzed data from 13 previous studies over the past four decades, looking for links between dehydration and alcohol consumption, and between drinking water and hangover intensity.
The first link is strong. “Alcohol has well-known diuretic effects,” Mackus writes, “which means that it promotes water and electrolyte loss through (increased) urine production.” Additional hormonal changes brought on by alcohol consumption, she adds, “do not stimulate the drinker to consume more water. The result of these processes is a state of dehydration, characterized by thirst and dry mouth.”
Less clear is the link between dehydration and what Mackus refers to as the “core hangover symptoms” — fatigue, nausea and headaches.
One study showed that, while thirst tends to decrease throughout the day after a night of drinking, it’s also a condition we experience whether we’ve been drinking or not. “These findings … suggest that, in contrast to the alcohol hangover, the dehydration effect is mild and relatively short-lasting,” she writes.
Another study of 462 Dutch students found that consuming water was the most popular method they used to mitigate a hangover, and had been practiced by 55.8 per cent of participants. (Other would-be cures included Aspirin, coffee, tea, breakfast, more alcohol and, at 55.2 per cent, “sleeping.”)
However, the participants reported that the efficacy of drinking water while hungover was relatively modest, with a mean score of 5.8 on a scale ranging from 0 (none) to 10 (excellent). And remember that the hangover goes away over time anyway, regardless of how it feels first thing in the morning.
A third study looked at water consumption among hungover people who participated in a 15-kilometre hike on the Greek island of Crete after a night of drinking; a seemingly cruel study, it must be said. But the authors of that study reported: “No significant correlations were found between the amount of consumed water and overall hangover severity.”
Mackus crunched the numbers further and writes: “Subjects with more severe hangovers consumed more water. However, the consumption of water did not significantly change their level of hangover severity.” In other words, the belief in the power of water continues, even though there’s no science to back it up.
She also takes to task makers of hangover remedies. “Several companies market hangover treatments claiming that dehydration is the cause of hangovers,” she writes. However, “aiming at developing a product that counteracts dehydration effects will not likely … be effective in reducing or preventing the alcohol hangover. These products might alleviate thirst and dry mouth, but the core hangover symptoms such as fatigue, nausea, and headache will likely persist.”
She adds: “In this context, it is important to note that in contrast to the core hangover symptoms, dehydration effects such as thirst and dry mouth have no relevant impact on mood and performance of daily activities such as driving a car or work performance.”
In addition to her scholarly paper, Mackus has included a slimmed down version of her findings on her LinkedIn page. In an emoji-laden post she writes: “Even guzzling water the morning after doesn’t significantly ease the severity of the hangover or quench that relentless thirst. Takeaway: Don’t rely on water alone to save you from that hangover headache. The science shows that hangovers and dehydration, though often occurring together, are separate beasts to battle.”
She concludes: “Next time someone offers you a glass of water as a hangover cure, you’ll know the truth! Cheers to informed — and responsible — drinking!”