If you are thirsty, it's too late!

Dr Neil Gardner, Contributor

Athletes often state they do not feel thirsty during competition and may trivialise the need to hydrate. Do not be fooled by lack of thirst. Strenuous exercise inhibits thirst sensors, even though you are losing water fast. There are three major consequences of a body that is short on water: overheating, disruption of chemical balances and dehydration. The chief problem is overheating.

Exercise increases body temperature in direct proportion to exercise load. Even in cool environments and with optimal hydration, exercise can raise core temperature to 103F within 15 minutes. Studies show that outside of the narrow range of 98-100F core temperature, your body will always sacrifice muscle function for temperature regulation. Decline in muscle function to complete immobility is not life threatening, but if body core tempera-ture rise a mere 9F, normal biochemistry cease and you die. This is particularly critical when you are training in the hot Jamaican sun.

Prehydrate

In London, it is important that our athletes perform pre-event water loading. The rule is: drink extra water for two days before the event, then between four to one hour before competition, drink one eight-ounce glass every 10 to 15 minutes.

Drink another two glasss between 30 and 20 minutes before the start. Gain bladder comfort again and drink nothing during the 20 minutes before the start, so that your stomach has a chance to be completely empty.

Drink During Performance

Do not try to 'tough out' training or competition without water. During exercise a common sweat rate is six ounces per mile of moderate running. When training, it is important to drink three and a half ounces every five minutes, just to try to keep up with the water lost in sweat, and it still may not be enough to prevent water depletion.

Rehydrate

After competition, immediately start drinking plain cold water. Avoid juices, especially citrus juices because sugar inhibits absorption and the citrus adds to stomach acidity and promotes cramping. Until you have already had at least four large glasses, avoid sodas, beer, fruit, candy bars, and all other sugary, fatty foods. Continue drinking extra water for the next 12 hours.

Maximise Absorption

Getting your body to absorb the water that you have drunk is the key. Research shows that cold water, below 50F (10C) is absorbed faster than room-temperature water. Gulping swallows air which disturbs stomach function and slows absorption so sip, don't gulp. Almost anything added to water slows absorption. Many sports drinks contain high levels of glucose, sucrose or other simple sugars. They inhibit absorption so do not use them during exercise. Avoid sodas and soft drinks.

Dr Neil Gardner is an Olympian, a doctor of chiropractic, and a diplomate of the American Chiropractic Neurology Board. They are located at: Gardner Chiropractic & Neurology Ltd, Suite 15, Braemar Suites, 1D-1E Bramar Avenue, Kingston 10.