In 1996, there was a concerted effort by health and fitness professionals to address the question of hydration for sport. The American College of Sports Medicine (1996) subsequently published a position stand on the issue, advocating athletes’ to drink as much water as possible at regular intervals. In 2007 the ACSM revised their position statement on hydration in relation to hydration volume, having come in for criticism of their position stand. Why?
The ACSM position stand was criticized and countered by eminent physiologists in the field, for example Dr. Tim Noakes (University of Cape Town). He argued that high volume hydration may lead to hyponatremia i.e. a state of excess water intake. Hyponatremia leads to a reduction in serum sodium concentration which in turn may induce symptoms of: confusion, disorientation, vomiting, nausea, cramps and fatigue.
As such, Dr. Noakes advocates a position of athletes’ being more in tune with their sensations of thirst, rather than drinking as much water as possible (2007). Some primary observations from his research include, but are not limited to:
1. World class marathoners drink very little during races, and well below their 1L.hr sweat rate. in fact, it is open to question whether hydration assists in the success of ultra-endurance athletes’ (even in difficult environments).
2. The addition of convective cooling e.g. wind blowing while athlete competes must be considered as a method of cooling and integrated into the equation when estimating the required hydration levels for an athlete.
A sensible position in regards to hydration is as follows: pre-hydrate at a rate of 200-250ml per 15min for 60min prior to competition. From there, replace water according to subjective perception of thirst afterwards.