When we feel thirsty, we drink something, that’s how it works, isn’t it? Actually a small drop in water levels in your body can have a big effect. We take in water through drinks and also contained in most of the food we eat. We lose it in more ways: in urine, through breathing and perspiration. Physical activity makes you lose more water, because as you get warmer you sweat more.

The surprising bit is just how much difference small water loss can make to athletic performance. A 3% loss of water leads to up to a 19% loss in muscle strength. You generally don’t feel thirsty until you get to about a 5% loss, and by that time you could be 30% down on strength. The solution is not to wait until you feel thirsty, and not even to rely on having a cuppa halfway through the round, but to have regular mouthfuls all the way through, say after every couple of ends. Try it and see what difference it makes.

What to drink? Well, water, but a small amount of carbohydrate and salt will help top you up. This is what isotonic sports drinks are all about – they have the same concentration of salt and glucose that is normally found in your body. So use them if you like. They can be expensive, though, and it is easy to make your own. A mix of half fruit juice and half water, with a pinch of salt per litre of drink will do the job. There are plenty more recipes for home-made isotonic drinks on the web as well.