It’s summer and here in Maryland it’s been a hot one. My outdoor bootcamps are in full force and everyone is working hard. I always encourage my clients to bring water and stay hydrated. It’s great getting out in the fresh air, but it’s important to take the proper steps to protect you from fatigue and heat-related diseases. Here are a few tips to help get you ready to head outside.
Beginning a workout fully hydrated or even “hyperhydrating” (hydrating to a greater degree than normal) before a workout can delay dehydration during exercise, maintain exercise performance and decrease the risk for heat-related illnesses.
Pre-exercise fluid intake enhances your ability to control body temperature and increases plasma volume to maintain cardiac output. You should drink enough fluids before exercising in the heat to begin every workout fully hydrated, and you should continue to drink during workouts longer than 1 hour. (See next section for specific guidelines of what to drink.)
A good indicator of your hydration levels is urine color. The lighter the urine color, the better the level of hydration. Your urine should look like lemonade rather than apple juice.
Before Exercise. Drink 500 milliliters (ml) 2 hours before exercise.
During Exercise. Drink about 200 ml every 15–20 minutes, aiming to match fluid intake to sweat loss. Maintain 400–600 ml of fluid in the stomach to optimize gastric emptying.
After Exercise. Drink 1 liter (L) per kilogram (kg) of weight lost during exercise.
Sodium intake is necessary only if exercise lasts more than 60 minutes or if you have a sodium deficiency. Before, during and after exercise, consume 0.5–0.7 gram (g) per L of fluid.
Drinks that contain glycerol cause fluid retention. This effect facilitates hyperhydration, protects against dehydration and maintains core body temperature.
Chronically exposing yourself to a hot and humid environment simulates adaptations that lesson the stress. Cardiovascular adaptations to exercising in the heat are nearly complete within 3–6 days. Full acclimatization becomes complete after 2 weeks as the increased sweating response catches up to the other adaptations. Therefore, take 2 weeks of slowly introducing yourself to the heat to be fully acclimatized and prepared for prolonged continuous exercise.