Chugging fluids to quench an intense thirst is like pouring water on a wilted plant. The feeling of thirst is a late signal that the body needs water, so relying on your thirst to tell you when to drink is not a good idea. By the time you are thirsty, the lack of water could already be affecting your health.
The best way to reduce the risk of heat illnesses while working or playing outdoors is to steadily replenish the water you lose as sweat. Drinking small amounts frequently, such as a cupful every 15 minutes, is more effective than large amounts less often. Three to four cups of water every hour are typically needed to replace fluids lost during strenuous work in the heat.
Because coffee, beer and other alcoholic drinks stimulate the loss of fluid as urine, they are poor choices for replenishing fluid in the body.
When starting a job in hot weather, or returning to work after an illness or extended break, you are more vulnerable to heat stress than after your body adjusts. Irregular schedules in some farm work and variations in summertime weather can make it harder to get used to controlling excess heat. As the body gets used to the heat over a period of 4 to 14 days, sweating becomes more efficient -- beginning earlier and carrying fewer electrolytes out of the body.
Although not always possible, it is a good practice to start by working only a part of the day and gradually increasing both work time and effort over the first week when the weather is very hot or humid.
If you cannot limit your work to get used to the heat, be especially alert for symptoms of heat illnesses.
For best protection from the heat, wear a loose-fitting, long-sleeved cotton shirt and light-weight cotton pants, a brimmed hat and sunglasses. Workers who are obese, pregnant, older and on certain medications should be aware they are at greater risk from heat.