Whenever air temperature, humidity (amount of moisture in the air), and sun intensity are high, children shouldn’t exercise as intensely. They also need to rest more often during any outdoor activities.
At the beginning of the summer, when starting a strenuous exercise program, or after traveling to a warmer climate, exercise should start off easy and then increase gradually (over 10 to 14 days), as your child gets used to the heat.
Make sure your child is always well hydrated, especially when exercising. As a rule, for every 20 minutes of physical activity, a child weighing 88 pounds (40 kilograms) should drink 5 ounces (a bit more than half a glass) of cool water; and an adolescent weighing 132 pounds (60 kilograms) should drink 9 ounces (a tall glass). Sports drinks that have salt in them aren’t necessary, but may be used if strenuous exercise is expected to last longer than one hour.
Clothing should be lightweight, light-colored, absorbent, and limited to one layer to help with evaporation of sweat. Change from sweaty garments to dry ones periodically.