Why you might experience polyuria during Freshers’ week

The countdown is on. Only seven days until UoN Freshers’ Week commences! Whilst the most important thing about being a fresher is settling in, making friends and exploring campus, we know the best parts are normally the socials and nights out. For most (with a few exceptions of those who don’t drink), we know alcohol is going to be number one priority for that first food shopping trip.

Whilst you’re busy partying hard there’s a lot of science that explains the changes in your body’s function that happens on a night out (probably the last thing on your mind, right?) – but it doesn’t harm knowing a few fun facts.

First thing’s first, alcohol is a diuretic; ‘diuresis’ means increased urinary excretion. I’m sure for those who are familiar with drinking, you may remember (or not) having to take more trips to the bathroom than normal (and not just to check out your hair or take a selfie). The consumption of alcohol causes the receptors for ADH or vasopressin, a hormone that acts on the collecting duct of the kidneys to conserve water, to switch off. So when the pituitary gland normally (and soberly) signals for ADH receptors to insert aquaporins to channel water back into the body it is allowed to filter out and more water is lost in urine.

Once you ‘break the seal’ on a night out, you might find that you keep having to go. 

This is because you’ve emptied the liquid you first started drinking and get rid of the excess liquid caused by the diuretic effect of alcohol. This means after consuming alcohol you’re excreting more liquid than you’re taking in (imagine the quantities in all those empty bottles!); for every 1g of alcohol, urine excretion increases by 10ml. And if you think you’ll just stick to shots to minimise the volume of alcohol, then think again; all alcohol has the same diuretic effect.

You may wonder why you feel so dehydrated at the end of the night or the next morning since you were taking in a lot of fluid.

But as explained above, you’re urinating more water than you’re taking in and this is happening so quickly in fact, that you are dehydrating yourself. Not to mention the extra fluid you’re losing through sweat busting those moves. The worst case scenario would be visiting the bathroom because you’re being ‘sick to your stomach’, to put it nicely, losing even more fluid. So, despite feeling like you’ve spent half the night in the ladies, drinking small amounts of water throughout the night and before you sleep will help the head the next day!

Even by trying to trick the brain with water instead of alcohol half way through the night, you’ll still end up losing about half of it and will still unfortunately be dehydrated. The only option is to stay up all night drinking water at certain intervals until the diuretic effect wears off and you can start conserving that precious water. But at that rate, you’d probably fall asleep on the bathroom floor since alcohol is a sedative. If you’re really trying to fight the hangover, having a teaspoon of salt before bed will help replenish the salts you’ve lost, or I suppose a portion of cheesy chips will do the job!