Let's face it, living in South Louisiana comes with its challenges when training for endurance races scheduled for the fall and winter. While most biking and running endurance races will take place during cooler weather, the actual training takes place during sweltering heat.
With heat indexes soaring over 100°F, it becomes difficult to find time to train for longer runs and rides during morning or evening hours. If you are training for one of these events outdoors in the heat it is important to eat and hydrate properly to prevent electrolyte imbalances, dehydration and to perform at your peak.
So, what is so special about exercising in the heat? First, with the presence of heat and humidity, the heat index rises. This is relevant to exercising outside because with increased heat and humidity it becomes harder for the sweat on your skin to evaporate, making it harder for your body to cool itself. Also, the hotter it is outside, the more you will sweat and the more fluid your body will lose, which will in turn increase your fluid needs.
In addition, the hotter it is outside, the hotter you can become inside. Consuming enough fluids can help lower your core body temperature, making it safer to exercise in the heat. In addition to keeping your temperature down, consuming enough fluids can prevent dehydration, which is not only a dangerous medical condition, but will also impair your exercise performance.
Which fluid is best to consume? Both water and sports drinks with 4 to 8% carbohydrate will work well to decrease core temperature and prevent dehydration. In addition to providing fluid, the carbohydrate sports drink will supply much-needed electrolytes lost in sweat and carbohydrate used for energy during exercise. When training sessions last longer than 1 hour, be sure to drink water and/or sports drinks every 20-30 minutes.
Staying hydrated while exercising is just as important as staying hydrated all day long. If you begin a training session dehydrated, your performance will be impaired and it will be more difficult to prevent dehydration while exercising.
How much is enough? Each person's individual fluid needs are different, due to each individual's body mass and sweat rates. The gold standard is to go by the color and volume of your urine. Your urine should be pale yellow and of adequate volume in relation to the amount of fluid you have consumed. If your urine is dark yellow or low volume, you may be dehydrated and need to increase your fluid intake. Disregard the color of your urine after taking multivitamins, since the color will be darker after taking vitamins.
Staying hydrated is not the only concern exercising in the heat creates. Research suggests that certain nutrients are utilized differently in hot environments versus cooler environments. For instance, when exercising in hot weather, your body uses carbohydrate more for energy than fat, so your carbohydrate needs increase. If you were exercising in the cooler months, you would not need as much carbohydrate as you do during hot weather. If you do not consume enough carbohydrate, your exercise performance will decrease. Take home message: do not skimp on the carbs when training for endurance events outside in the heat.
How much carbohydrate you need to perform at your best is totally individualized depending on the type of event you are training for. In general, you need to consume carbohydrate before, during and after an endurance training session. You also need to ensure you are consuming enough carbohydrate at your meals and snacks. Examples of carbohydrate dense foods include: dried fruit, grains (rice, noodles, pasta), breakfast cereal, granola, sports bars, smoothies, liquid meal supplements, frozen yogurt, sports gels and carbohydrate containing sports drinks.
Training for an endurance race is not a time to cut back on calories to lose weight, especially during hot months. Due to your increased carbohydrate needs your total calorie needs will increase during this time. Do not cut back on much needed protein or fat to ensure adequate carbohydrate intake. If you are trying to shed some extra pounds and are training for an endurance event outdoors, make an appointment with a Registered Dietitian specializing in sports nutrition to ensure you are getting enough nutrients to fuel your activities.
Rebecca M. Lee, RD, LDN, is the registered and licensed dietitian/nutritionist at East Jefferson General Hospital's Wellness Center. Lee specializes in adult weight management, chronic disease prevention and sports nutrition. To schedule an appointment with Lee, call: (504) 849-6801, (504) 849-6868 or e-mail: firstname.lastname@example.org.