Abstract : The Importance of Hydration for Optimal Performance

This is the abstract of the paper presented by Prof Dr. Rabinderjeet Singh during the Sports Hydration and Nutrition Seminar.

Water is the body’s most important nutrient; it makes up 70-75% of the total body weight, and is needed in every bodily function. Therefore, satisfying our body’s water requirements is essential for good health and excellent physical performance. As major sports events in Asia are usually staged in hot environments with average daytime temperature of 29-32 degrees Celcius and average relative humidity of 70-90 percent, it is generally understood that prolonged bouts of exercising under these conditions can lead to a loss of one litre of body fluid per hour. This can have an adverse effect on the body’s cellular environment. Dehydration and hyperthermia can adversely affect mental and physical performance. The rapid replacement of fluids following a bout of exercise becomes the paramount concern to an athlete who may have to perform more than one such bout in a single day. Meeting water requirements under environmental conditions that promote large losses is not easy. Furthermore, water intake during exercise is usually inadequate and ‘voluntary dehydration ‘ occurs. A competing athlete may be near exhaustion despite absence of thirst. The athlete must begin the exercise fully hydrated and regular ingestion of fluids is beneficial when the exercise duration exceeds 40minutes. It is therefore pertinent to drink enough fluids before a game and during breaks to avoid dehydration and fatigue. Dilute carbohydrate-electrolyte drinks are best for fluid replacement while also supplying some substrate for the exercising muscles. Even after the exercise, thirst may not be sufficient stimulus to ensure full rehydration. What is ingested during recovery, especially in the first two hours, could also markedly influence the rate of recovery and performance in a subsequent athletic events. Athletes, especially in the tropics, are advised to drink to replace their sweat losses rather than simply to satisfy their thirst. The rehydration fluid must contain sufficient sodium to maintain the thirst stimulus and to promote the retention of the ingested fluid.

Applications:

• Dehydration and hyperthermia can acversely affect mental andphysical performance.
• Begin exercise fully hydrated and regular ingestion of fluids is beneficial when the exercise duration exceeds 40 minutes.
• Dilute carbohydrate-electrolyte drinks with sufficient sodium are best for fluid replacement, which not only supply some substrate for the exercising muscles but also maintain the thirst stimulus to promote the retention of the ingested fluid.