Summer is the perfect season for exercise buffs: The days are longer, the weather is consistently better, and cooling down requires porch-sitting with recovery beer.
But as temperatures rise into the triple digits, Exertional Heat Illness (EHI)—an umbrella term for heatstroke, heat exhaustion, heat syncope, and heat cramps—can interfere with your training and your health if you don’t take the right precautions.
We spoke with heat-related illness specialists Dr. Douglas Casa, a professor of kinesiology at the University of Connecticut; and Dr. Michael F. Bergeron, the heat, hydration, and research advisor to Major League Soccer, for some safety tips on staying active in the heat.
Knowing the symptoms of EHI and paying attention to your body are extremely important if you want to exercise safely in the heat. It’s easy to brush off a headache during a pickup basketball game, or attribute weakness and fatigue during a run to something like not getting enough sleep the night before, but your situation may be more serious than that.
Headache, dizziness, nausea, fatigue, and lightheadedness are all telltale signs of heat exhaustion according to Casa, whos is also the CEO of the Korey Stringer Institute, an exertional heat stroke prevention institute. Becoming disoriented or blacking out are both signs of heatstroke, which is a much more serious—even fatal—condition that requires immediate medical attention.
If you find yourself possibly suffering from heat exhaustion, Bergeron advises stopping what you’re doing and moving to a shaded or air-conditioned area immediately. Remove any excess clothing, lay flat on your back with your legs elevated, re-hydrate, and wait at least a day before working out again.
Having a motivator, a competitor, or just someone to talk to always makes a workout more fun. But working out with others is good for safety reasons as well, especially when exercising in the heat.
Bergeron, who doubles as president and CEO of Youth Sports of the Americas—a group that promotes health and safe exercise for children—suggests always making sure someone is there in case anything goes wrong. Your workout buddy can also be the voice of reason those times when you want to keep going, but doing so maybe wouldn’t be the best idea.
Staying hydrated is key to staying healthy, especially when you’re working out on a scorching day. Drinking water improves your ability to sweat, a process that cools you down; and it replenishes liquids lost to sweat.
The three key factors that determine how much fluid you need, says Casa, are the intensity of your workout, environmental conditions, and your weight. For example, if an offensive lineman loses 3 liters of water in the same time a cyclist might only lose 2 liters, that doesn’t mean the football player is more dehydrated.
Bergeron generally recommends drinking about 16 to 20 ounces of fluid per pound of body weight lost during exercise. It’s important to spread this out throughout the day and not consume it all at once if your body’s water deficit is large. It’s just as important not to wait to drink until you’re thirsty, as that’s a sign you’re already slightly dehydrated.
Working out early in the morning or late in the evening is best during the summer since it won’t be as hot out, and daylight is more widely available. This time frame can fit perfectly with most people’s work schedules: If you don’t feel like going for a bike ride at 6 a.m. before work (we understand completely), you can do it in the evening when you come home. (And for those on the night shift, you can finally work out outdoors when you wake up!)
But sometimes, afternoon workouts are inevitable. If your field hockey games are every week at 2 p.m., Casa says you need to be training in that type of heatall the time so you’re used to it. With that said, work your way up to it—don’t just start doing intense workouts in the sweltering heat from the start. It’s okay to take breaks and go slow.
It’s important to fill your workout wardrobe with clothes that keep you cool and dry on days where it may feel like you’ve taken up permanent residence on the sun. Bergeron advises wearing items that are lightweight, breathable, and thatprotect your skin from UV radiation. Dry-fit clothing, which helps wick moisture and prevents the buildup of excess body heat, is also a great option.
Fueling your body with foods that won’t dehydrate you is crucial when doing any type of activity on a hot day. Bergeron recommends avoiding foods that are high in fat and protein before exercising since they require time and energy to digest. As you exercise and your body heats up, blood flow to the GI tract decreases, which makes digestion more difficult and may cause nausea.
Instead, aim for hydrating foods that have high water content. Apples, melons, cucumbers, berries, grapefruit, avocado, and lettuce, among others, will all cool your body and keep you hydrated. But don’t worry: You can always have that big bowl of pasta you can’t stop thinking about during recovery.