The dreaded hangover – headaches, fatigue and nausea are normal Sunday morning sensations for many a Saturday night reveller. Dehydration is frequently said to be the reason for hangover symptoms – and some swear that a pint of tap water before bed thwarts any alcohol-induced ill-effects. But given the amount of fluid drunk during a night on the town, it sounds like quite an odd idea.
So just how dehydrating is alcohol – and can lack of water really explain a hangover? The data is difficult to find: no-one seems very interested in researching hangovers these days. It’s therefore time to blow the digital dust of a seventy year-old research paper to find an answer…
How much does alcohol dehydrate you?
The answer can be found in a piece of research from 1950. Back then, scientists were still bickering over whether a pint of beer makes you wee more than a pint of water (it does). To lay the issue to rest, three hospital researchers decided to crack out a bottle of whiskey.
Three volunteers (surely not the researchers?) were invited to sink a good portion of bourbon on an empty stomach – five hours after breakfast. Their urine output and composition were monitored over the next six hours. Just to be sure, blood samples were taken to test salt levels and kidney function. I know what you’re thinking, bourbon isn’t real whiskey, but let’s not get too picky.
Using the same volunteers on different occasions, they compared bourbon drinking to drinking equivalent amounts of water. They discovered that after five shots of bourbon, about 600ml of extra urine was passed. So that’s 120ml worth of dehydration per unit of alcohol (approximately). One has to assume that the volunteers were helped to walk to the toilet for this part of the procedure.
Helpfully, the researchers also wanted to find out if drinking tap water alongside alcohol could negate its dehydrating effects. The final test was to drink five shots followed by one and a half pints of water. Apart from the fact that they will have spent a long time on the toilet – the results showed that tap water did indeed reduce the dehydrating effect of alcohol by about a half.
Does drinking water prevent a hangover?
We now know that alcohol impairs the kidney’s ability to make normal strength urine – and even drinking lots of water won’t stop that. If you consider that for every unit of alcohol you drink you are losing a small cup-full of body water down the toilet bowl, it might make you think more about interspersing your night-out with some soft drinks.
To summarise, it would appear that tap water may go some way to prevent a hangover the next morning – but it won’t cure it. Crucially, there are other chemicals produced in the body from alcohol that also play a part in a hangover (look up Acetaldehyde).
Of course, I could tell you that there is only one way to never have a hangover again – but you probably know that one already.
Thanks for reading – feel free to comment below…
Strauss, M., Rosenbaum, J., & Nelson, W. (1950). THE EFFECT OF ALCOHOL ON THE RENAL EXCRETION OF WATER AND ELECTROLYTE 1 Journal of Clinical Investigation, 29 (8), 1053-1058 DOI: 10.1172/JCI102336