Heat, Hydration and Exercise
by Jeremy Gentles, MA, CSCSAs summer temps rise, so does the risk of falling victim to heat-related illnesses such as heat cramps, heat exhaustion and heatstroke. Fortunately, heat-related illnesses are nearly always preventable. Due to the restrictive nature of weight loss surgery, those who have had WLS and plan to be active outdoors during the summer must be extra vigilant in their efforts to properly hydrate and employ additional measures to successfully and safely participate in outdoor summer activities.
Heating It Up
Just standing outside in hot weather can cause a person to sweat, so it is no mystery that exercising or even being moderately physically active in hot weather, places more stress on the body. As body temperature increases with both exercise and hot or humid weather, blood flow is diverted to the skin and away from muscles, the brain and other organs. (Why, oh why, is the brain always getting in the way?) Just as the radiator of a car helps to maintain proper engine temperature, blood is diverted toward the skin to dissipate heat. Since muscles and useful organs, such as the brain, require significant blood flow, excessive temperatures may divert enough blood flow away from these organs to cause reductions in mental ability, strength and endurance, which can also present a serious danger.
In addition to diverting blood flow toward the skin to control body temperature, sweat is also produced in order to cool the body. Sweat evaporates from the skin and takes a bit of heat along with it (convection). Unfortunately, high humidity prevents sweat from evaporating and therefore decreases the body’s ability to cool itself with sweat. In most situations, the body can adequately handle the heat produced during exercise and/or high temperatures. However, prolonged periods of exercise in hot or humid conditions, especially when fluids and electrolytes are not consumed in proper quantities, can result in heat-related illnesses such as heat cramps, heat exhaustion and, in some cases, heatstroke.
In addition to diverting blood flow toward the skin to control body temperature, sweat is also produced in order to cool the body. Sweat evaporates from the skin and takes a bit of heat along with it (convection). Unfortunately, high humidity prevents sweat from evaporating and therefore decreases the body’s ability to cool itself with sweat. In most situations, the body can adequately handle the heat produced during exercise and/or high temperatures. However, prolonged periods of exercise in hot or humid conditions, especially when fluids and electrolytes are not consumed in proper quantities, can result in heat-related illnesses such as heat cramps, heat exhaustion and, in some cases, heatstroke.
Simple Strategies to Stay Safe
Avoiding heat-related illnesses is generally fairly straightforward, but in our “hurry-up” lifestyle, sometimes we forget to keep our safety in mind. Follow the tips below to avoid heat-related illnesses as the temps outside heat up.
- Fit or unfit. As you become more fit, your ability to tolerate exercise and physical activity in hot and humid conditions will also increase.
- Take your time. Even if you are a rather fit individual, suddenly changing from an exercise routine performed indoors to an exercise program outdoors in the middle of the summer is probably not a wise choice. Just as it requires time to acclimate to new climates, if you need or want to begin exercising more outside during hot and humid times of the year, start with shorter periods of time and gradually increase the time spent exercising outdoors. Of course, you could also choose to exercise during the coolest part of the day, assuming your schedule permits, or exercise indoors on days that are too hot to be outdoors.
- Wear proper clothing. Loose fitting, lightweight and light-colored clothing are best. Many “wicking” fabrics are also available that often help cool the body better than fabrics such as cotton.
- Know Your Limits. If you experience weakness, headaches, dizziness, muscle cramps, nausea/vomiting, or rapid heartbeat, get out of the heat and stop exercising. If your temperature exceeds 102° F, seek medical attention.
- Drink up. Perhaps the most important and common sense weapon against heat-related illnesses is proper hydration. Consuming adequate fluids and electrolytes, prior to, during and after exercise in hot and humid conditions is extremely important. Do not wait until you are thirsty to begin replacing fluids; by that time you are already behind in your water consumption. For periods of long exercise, electrolyte replacement should also be considered. Sport drinks, such as Gatorade, can be used for hydration and electrolyte replacement. You can also use water in combination with carbohydrate/electrolyte gels or other supplements.
A Bit More About Hydration
Due to the restrictive nature of weight loss surgery procedures, fluid and electrolyte consumption are often compromised. If you are going to be exercising in fairly high heat or humidity, it is imperative that adequate fluids and electrolytes are consumed. It is also important to consider that being overweight or obese also compromises the body’s ability to cool itself. If you know that you will be exercising outside in the heat and humidity, plan to start hydrating several hours before the exercise or activity begins. If the exercise session is greater than an hour, fluid, carbohydrate and electrolyte beverages or supplements should be considered. Once exercise is complete, fluid consumption replenishment should continue.
Since body size, temperature, humidity, fitness level, and exercise choice are all variables to consider, there is no “one size fits all” approach to hydration and electrolyte replacement. But, if you follow the strategies discussed above, make common sense decisions and adjust your exercise level if needed, participating in outdoor summer activities can be done safely and successfully.
Since body size, temperature, humidity, fitness level, and exercise choice are all variables to consider, there is no “one size fits all” approach to hydration and electrolyte replacement. But, if you follow the strategies discussed above, make common sense decisions and adjust your exercise level if needed, participating in outdoor summer activities can be done safely and successfully.
Comment below to share your summer hydration tips, questions, and concerns.
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