I am a major believer in the importance of hydration in all that we do. As a scuba diver, I have come to realise that dehydration is one of the biggest issues in decompression sickness, and over the past few years, the fact that dehydration is a factor in many other maladies (non-diving) has become clearer and clearer to me.
Over on the Men’s Health website there is a good short article on staying well hydrated, especially when exercising.
In short, I aim to drink around 3–4 litres of water per day, upping that to 4–5 litres on days when I’m training. I also work to the rule that any cup of coffee (or caffeinated soft drink) will “cost” me an additional 500ml of water. Coffee now is a once a week thing for me in general, and I also limit soft drinks to a single can per week of a diet variery. Apart from plain water, I drink mineral water (non–flavoured) and green tea, as well as protein shakes, and the odd fruit juice.
In the dojo, I allow, actually encourage, students to bring a bottle of water and keep it at the side of the room, and I give plenty of water breaks. In hot weather, the number of short water breaks increases.
Consider good hydration to be an important part of your training and nutrition strategies.