Can I check my hydration levels via my urine?
Wondering whether checking the colour of your pee is an effective way of monitoring your hydration status? We take a look at the evidence
The general rule has usually always been, the darker the colour of your urine, the more water you need (and maybe electrolytes, too). Most of us will have a darker urine colour after we exercise, even if we’ve been hydrating, so checking both before and after to get a better idea of your hydration levels can be a good idea.
However, we need to bear in mind that while it can be a useful indicator it’s not definitive. In a recent study Dr Hew-Butler found that while there’s definitely a relationship between how much we drink and the colour of our urine, that doesn’t necessarily always correlate with our actual hydration status at a blood and cellular level (where it really matters).
The study showed that, “a urine osmolality above 700 mOsmol/kgH2O would classify >50% of athletes as dehydrated, in a spot sample hydration check, despite normal blood sodium concentration, potassium concentration and osmolality values that would confirm the athletes were euhydrated (normonatremic) at rest.”
I personally find this extremely interesting because I’ve increasingly felt that the apparent obsession with ‘peeing clear’ is not necessarily a completely helpful a message to be promoting to athletes. I’ve seen it drive some pretty questionable behaviours in my interactions with sports people (from elite to amateur) over the years, myself included! I’d go so far as to say that it can actually be counterproductive in some circumstances.
The colour of your pee can depend on a variety of other factors, apart from your hydration levels, including:
- Drinking alcohol
- Drinking a lot of tea, coffee or other mildly diuretic drinks
- Swimming in cold water (due to cold diuresis and/or immersion diuresis)
- Drinking a large amount of plain water in a very short space of time
- Nerves
- Certain medication
The key thing is not to place too heavier emphasis on urine colour, and not to use it as your only hydration monitoring metric, instead you should use it as part of a larger hydration strategy. Because although being chronically dehydrated is definitely bad, you don’t don’t want to be over-drinking and forcing your body to urinate more frequently than is necessary just so you have clear pee the whole time.
If you’re regularly nearer to the darker end of the scale, then it might be worth experimenting with taking in a little more water or sports drinks, especially around times when you’re working hard and sweating a lot. See how that makes you feel and whether it’s of benefit.
Conversely, if you’re always seeing very light coloured pee, then maybe you could think about dialling back your fluid intake a touch to see if you’re over-doing it a bit.
Again, how you feel overall after making these adjustments will give you the best idea of whether you’re better or worse off as a result, and that is of course what actually matters most of all.
You can find out more about hydration and how to improve your hydration strategy at www.precisionhydration.com
Image: Getty Images
Andy Blow
Sports scientist 
