Yesterday I suffered the worst muscle cramps I have ever experienced (near the end of a 70 mile ride). I don't consider this a great distance and wasn't expecting this problem. In restrospect the conditions were not good. Having worked in the morning, I set off at 1230. The hottest part of the day, in the hottest month of the year here in Thailand. The forecast had said 35 C in the shade, but it seemed a bit hotter, and anyway I wasn't in the shade. The first two hours were great but during that time I only drank 1.5 litres of fluid. Dehydration undoubtedly played a part in my problems, and by the end (4 1/2 h) I was feeling weak and suffering badly with muscle cramping. My question is, what do you long distance cyclists do to avoid muscle cramps? When cycling in hot conditions (say into the mid 30s celcius), how do you manage to keep up your fluid intake? And if you do start cramping up, what do you do?