When playing sports on hot days, be aware of the risks of heat-related illness.

Healthy Hints to Avoid Heat-Related Illness

At this time of year, it’s important to take precautions to avoid heat-related illness, which can develop rapidly when your body is unable to keep itself cool.


The Centers for Disease Control (CDC) recommendations for preventing heat-related illness emphasize staying cool, which may mean staying indoors in air conditioning on very hot days. But not all of us have air conditioning, and when it’s a beautiful weekend, of course we all want to be outside!

So here are the signs to look for that may signal the onset of heat-related exhaustion:

  • Excessive sweating
  • Heat rash
  • Darker colored urine
  • Rapid heartbeat and pulse
  • Feeling lightheaded or faint
  • Weakness and fatigue
  • Muscle and/or abdominal cramps
  • Nausea and vomiting

If signs of heat exhaustion are not recognized and activity continues, you may develop signs and symptoms of heat stroke, which may include:

  • Fever over 104 degrees
  • Dry, hot, red skin
  • Lack of sweating
  • Rapid, strong pulse
  • A high body temperature
  • Confusion, bizarre behavior or possibly unconsciousness

Signs of heat stroke are a true medical emergency. Call 911 immediately and move a person to a cooler environment. Quickly attempt to reduce body temperature with cool compresses, ice packs or even an ice bath. Stay with the person until help arrives.

How to Decrease Your Risk for Heat-Related Illness

The best way to protect yourself is to be aware of risk factors that increase your chance of becoming ill. These include:

Environment: Playing outdoors sports, such as football, in hot weather can lead to heat illness. Your risk also increases if you suddenly move from a cooler to a hot climate and aren’t used to it.  In this case it’s best to limit your activity for a few days and allow your body to acclimatize to the change.

Dehydration: The amount of sweat that a person can potentially lose in an hour can be a liter or even two, so you have to drink a lot of water when exercising in heat – more than most people plan for. Humidity plays a large role in heat illness because when it’s humid, our cooling mechanisms are diminished and sometimes we don’t even realize how much water we might be losing. Pre-hydrate before exercise, carry plenty of water, and stop to drink frequently.

Body Mass: Those with a high BMI are more at risk of heat-related illness.

Clothing and gear: Thicker clothing and sports gear that includes padding decreases the body’s capability for heat evaporation. Helmets can increase risk for overheating since you lose heat through your head. Certain fabrics and types of clothing such as bike gear containing spandex also retain heat. Look for moisture-wicking fabrics and clothing designed for breathability. Hats are a mixed blessing; they protect from glare and UV rays but can trap heat. The best hats for hot days are loose and made of breathable fabrics.

Age: At a very young age and in adults over 65, the central nervous system is less efficient at regulating temperature, partly because we don’t sweat as much, and sweating is an important part of the body’s heat-regulation mechanism. Both age groups often have difficulty hydrating regularly. Seniors also store fat differently, another factor in heat-regulation.

Certain drinks: Coffee, soda, energy drinks and caffeinated teas are dehydrating, as they increase urination. Drink water and electrolyte beverages that are low in sugar instead.

Alcohol: Like coffee and tea, alcohol is hyper-osmotic, causing your body to lose fluid. And because alcohol alters your mindset, it may skew your perception of how hot you are. If you’ve had any alcohol to drink, wait until another time to exercise.

Health conditions: Many health conditions increase your risk of heat illness. Diabetes, kidney issues, and sickle cell trait affect fluid in the body, and anyone with heart or lung issues needs to be extra careful. Medications such as diuretics, beta-blockers and stimulants can affect your susceptibility to heat illness so check with your doctor about any medications you’re taking.

What to Do If You Start Feeling Sick in the Heat

If you feel you’re becoming overheated, it’s important to take steps immediately to cool down and get help. Start by getting into the shade, drinking fluids, and get some ice or if possible take a cold shower or bath. To start the cooling process more rapidly, place ice packs around the body. At races, medical tents will often put those with heat-related symptoms in an ice bath.

Heat illness symptoms can progress rapidly, so if there’s any concern, get emergency treatment right away.

How Do I Protect Myself When I’m Outdoors in the Heat?

Train early in the morning or in the evening when temperatures cool.  Stay in the shade whenever possible. Drink plenty of water. Wear loose, lightweight clothes. Take advantage of moving air; use a fan or look for a breeze.  Cool down with cold showers or iced towels.

Updated June 23, 2022

Asha Mehta, MD, currently works at the minor injury center at Kaiser Permanente San Francisco, helping patients manage both acute and chronic musculoskeletal issues. With board certifications in internal medicine and sports medicine, she integrates these areas of expertise to promote a healthy, active lifestyle and help patients be at their very best. Since childhood, Dr. Mehta has played soccer and tennis. She stays fit with yoga, pilates and weight training, runs the occasional 5/10K or 1/2 marathon and plays soccer for the Golden Gate league in San Francisco.