You should be drinking enough fluid that your urine is clear or pale yellow. Avoid prolonged outdoor activities such as hard labor, jogging, tennis, racquetball, etc. If you feel you must exercise, swimming is recommended. It is important to avoid alcohol and caffeine, which cause the body to lose fluid. A cold beer may sound good, but avoid it.
Clear liquids are best preferably water.
Other good choices include lemonade and juices. This causes excessive sweating, which removes large quantities of salt and fluid from the body. This condition happens abruptly and is considered an emergency. It is more common in the elderly, the young, and can be a threat to athletes.