Since the hot weather is here, it’s time to pay attention to fluids. Dehydration is a common cause of poor performance in athletics, but more seriously it can lead to life-threatening heat illness. Every year athletes and recreational outdoorsmen suffer from heat illness with a small number going on to die from heat stroke.
Under normal conditions, with little or no physical activity, the average adult loses between 2-3 liters of fluid in a day. Physical activity greatly increases fluid losses—sometimes up to 5 liters per day.
In order to prevent dehydration, adequate fluid intake should occur well in advance of the anticipated activity. We should all be drinking small amounts of liquids throughout the day:
- It is also recommended to take in about 500ml of fluid about 2 hours before exercise.
- To top off the tank on hot days, 250 ml should be ingested about 1 hour before the event.
Drinking small amounts of fluids during the activity is critically important to maintaining hydration. Research has revealed that we are more likely to drink chilled, flavored drinks. Sports drinks that contain some sugar and sodium have also been shown to be better absorbed by the stomach than plain water. In many ways, sports drinks were designed specifically for athletes from taste right down to content to match their needs. Drinks to avoid are ones with a sugar load greater than 8%, like fruit juices, and any beverages that contain caffeine or alcohol. Be very cautious with so-called “energy drinks” which often contain high levels of caffeine or other stimulants. Due to their diuretic effects, they will worsen dehydration rather than replenishing your fluid deficit.