A widespread heat wave is moving across the United States, and for anyone hoping to stay active outdoors, a few adjustments to eating, drinking and timing can make a major difference. While extreme heat poses real health risks, experts say summer fitness routines do not have to come to a complete stop.
Extreme heat is generally defined as a stretch of high heat and humidity, with temperatures climbing above 90 degrees Fahrenheit for two or three days or longer. During these periods, the body has to work harder to regulate its temperature, which raises the risk of heat-related illness. Older adults, children and people with certain chronic conditions face the highest risk.
Know the warning signs of summer heat stroke
Heat stroke is the most serious heat related illness and occurs when body temperature rises to 106 degrees Fahrenheit or higher within 10 to 15 minutes, a level that can quickly become life threatening. Warning signs include loss of consciousness, confusion, slurred speech, profuse sweating, hot or dry skin and seizures.
If these symptoms appear, calling 911 immediately is critical, along with cooling the body as quickly as possible using cold, wet cloths or an ice bath. Moving the person to shade, removing excess clothing and increasing airflow around them can also help while waiting for emergency help to arrive.
These symptoms are especially important to watch for during outdoor exercise or athletic events. An estimated 9,000 high school athletes are treated for heat related illness in the United States each year, and even elite athletes are not immune. Research from the Tokyo 2020 Olympic and Paralympic Games found that roughly one in 100 athletes developed a heat-related illness during the competition.
What to eat before a workout
Before exercising in the heat, easily digestible, hydrating foods are key. Light snacks with high water content, such as watermelon with a pinch of sea salt, a smoothie or a frozen banana paired with nut butter, can provide quick energy without weighing down the stomach.
Carbohydrates from fresh fruit, including bananas and berries, help fuel the body ahead of moderate to high intensity workouts and can delay fatigue. For longer workouts in hot conditions, sports medicine experts recommend consuming roughly 30 to 60 grams of carbohydrates per hour of activity, while limiting dairy and high fiber foods beforehand to avoid digestive discomfort.
Timing meals throughout the day
How meals are spaced out matters just as much as what is on the plate. Heavy, high fat meals immediately before exercise can slow digestion and contribute to sluggishness in the heat. Nutrition experts recommend eating several smaller meals spaced about an hour and a half to two hours apart, rather than relying on three large meals.
Recovery should also begin quickly. Rather than waiting until after showering and changing to eat, experts suggest starting the recovery process within about 15 minutes of finishing a workout.
What to eat after exercising
Post workout nutrition becomes especially important during hot weather, when the body needs to rehydrate, refuel and repair muscle tissue. Combining 20 to 30 grams of protein with a source of carbohydrates within a few hours of finishing exercise helps replenish glycogen stores and support recovery.
Options like peanut butter, yogurt, cottage cheese or a protein smoothie paired with a turkey sandwich on wheat bread can cover both needs at once.
Hydration and electrolytes
Staying ahead of thirst is one of the simplest ways to avoid dehydration. For workouts under an hour, water is usually enough, but for sessions lasting longer than an hour, drinks containing electrolytes can help replace what is lost through sweat.
Water rich foods such as watermelon, oranges, berries and cucumbers can also support hydration after longer sessions. A protein shake made with fruit and coconut water offers a combination of fast digesting carbohydrates, protein and electrolytes in one option.
Limiting caffeine in the morning before a workout is also worth considering, since one or two cups of coffee is generally fine, but anything beyond that can contribute to dehydration. A quick way to check hydration status throughout the day is to look at urine color, with pale yellow generally indicating adequate hydration and dark amber suggesting a need for more fluids.
Choosing the best time to work out
Timing outdoor activity wisely can make a significant difference in how the body handles heat. The safest windows are generally early morning, before 9 a.m., or in the evening after the sun begins to set, when air and pavement temperatures are lower.
Exercising between 9 a.m. and 4 p.m., and especially during the peak window of 11 a.m. to 3 p.m., carries the highest risk of heat exhaustion. Humidity adds another layer of difficulty, since it slows sweat evaporation and makes it harder for the body to cool itself naturally.
With the right combination of timing, hydration and nutrition, experts say outdoor activity can remain part of a healthy summer routine, even as temperatures continue to climb.
