How much to drink while cycling?
Riding a bicycle is the most efficient method of locomotion. By bicycle, one gets the furthest with a given amount of food (energy). This is true even though human is a very inefficient heat machine. Only about 25% of the energy ends up in useful movement, the rest becomes heat. To get rid of the extra heat derived from food while cycling, the cyclist will usually sweat. Only in very rare circumstances, such as riding slowly in cold weather, other forms of heat transfer (convention, radiation, etc) are sufficient. So, the cyclist sweats. The hotter it is and the faster the cyclist rides, the more he or she sweats. The cyclist is made of 60 to 70% of water, which makes sweating easy. There is plenty of water. Unfortunately, the human machine is rather delicate. Losing only 2-4 % of body weight as sweat both decreases efficiency and can lead to health problems, and if not replaced, may lead to heat exhaustion, and finally death. To maintain efficiency and to stay alive, the cyclist...