Blame Global-Warming, or El Niño, or just crazy Melbourne weather, but this summer is hotter and longer than any Melbourne summer that I can remember.
In summers like this (and if you play any kind of sport) the one-size-fits-all approach of drinking 2 litres per day doesn't cut it.
If you want to stay active this summer, you definitely need more than just 2L of water per day.
The science of hydration can be seriously complicated, but I have found a relatively simple formula that will make sure you drink enough water — even if it's 40 degrees or you're playing tennis.
n summer, your base daily intake should be 2.5L. That will make-up for the water we use as part of our metabolism, and the water we lose because of moderate sweating due to heat. However, 2.5 litres does NOT account for increased sweat due to exercise, or the increase in urination caused by diuretics. Therefore you need to add to your 2.5L goal:
Add 200mL (1 glass) to your daily goal for every shot of coffee and/or standard drink of alcohol. This is because caffeine and alcohol cause an increase in urination.
Add 200mL (1 glass) to your daily goal for every 30min of resistance exercise (e.g. weight lifting) you undertake in a day
Add 400mL (2 glasses) to your daily goal for every 30min of cargo exercise (e.g. running) you undertake in a day.
So, if you have a coffee in the morning, go for a 5km run before work, then have a red wine with dinner, you need 2.5L + 200mL + 400mL + 200ML = 3.2L of water that day.
More than 3 litres of water per day sounds like a lot, but you can mix it up with some other drinks. Sugary drinks DO NOT count towards your total, but pure fruit juice and sugar-free sports drinks DO count.
If you want more information on hydration, email me directly via the contact page.
Dr Mitch Clark