3 WINS Fitness recommends no testing or intense activities at or above 90 F, especially if humidity is above 35%. Please review the information below related to hydration/fluid replacement.

Pay attention to following symptoms when exercising on a hot day:

• Higher than normal heart rate during exercise.
• Very rapid breathing.
• Heavy sweating, sometimes followed by a decrease in sweating.
• Confusion, dizziness or disorientation.
• Pale skin.
• Extreme thirst and dehydration.

Treatments for heat stress

• Stop exercising.
• Move to a shaded or air-conditioned area.
• Remove excess clothing or equipment.
• Drink cold beverages.
• Sit in front of a fan.
• Put chilled cloth around neck.
• Place entire body in cool water.
• If you are feeling very hot and begin to have trouble concentrating, contact emergency services immediately. In addition, if any of the above symptoms persist despite treatment, contact emergency services.

Fluid Replacement Recommendations

Before Exercise
Prehydrating with beverages, if needed, should be initiated at least several hours before the exercise task to enable fluid absorption and allow urine output to return toward normal levels. Consuming beverages with sodium and/or salted snacks or small meals with beverages can help stimulate thirst and retain needed fluids.

During Exercise
Individuals should develop customized fluid replacement programs that prevent excessive (<2% body weight reductions from baseline body weight) dehydration. The routine measurement of pre- and postexercise body weights is useful for determining sweat rates and customized fluid replacement programs. Consumption of beverages containing electrolytes and carbohydrates can help sustain fluid-electrolyte balance and exercise performance

After Exercise
If time permits, consumption of normal meals and beverages will restore hydration. Individuals needing rapid and complete recovery from excessive dehydration can drink ~1.5 L of fluid for each kilogram of body weight lost. Consuming beverages and snacks with sodium will help expedite rapid and complete recovery by stimulating thirst and fluid retention. Intravenous fluid replacement is generally not advantageous, unless medically merited.

Additional Resources

ACSM Information on Exercising in Hot and Cold Environments
ACSM Position Stand on Exercise and Fluid Replacement