Should I Exercise in a Heat Wave?

Are you telling yourself it’s too hot to exercise? Should I exercise in a heat wave? How am I going to stay fit? Lazy days of summer can often lead to reduced levels of activity and may lead to complications down the road. But how hot is too hot? There are two factors that determine just how hot it feels:

    1. Air Temperature
    2. Humidity

Generally speaking, when the heat index is over 90 degrees you should use caution when exercising outdoors. When it is too hot the risk of heat-related illness rises significantly. While exercising outdoors in warmer weather is safe, consider the following suggestions when exercising to prevent the adverse effects of heat-related illnesses:

  • Get Your Workout in Early: Structure your exercise early in the morning or evening when temperatures are cooler. The hottest time of the day is typically around 11-4 pm.
  • Head Indoors: If you are not able to avoid the heat, consider going to a mall or public that has air conditioning. The Orange County Sheriff’s Department published a list of cooling centers that can be found here: 2022 Cooling Center Locations
  • Join a Class: Several exercise courses are available online and at your local gym. Swimming is also an excellent way to exercise during a hot day.
  • Dress Smart: Wear a hat and loose, light-colored clothing. There is plenty of activewear these days designed to keep you cool. Protect your eyes and skin from the damaging rays of the sun. Make certain your sunglasses are polarized to maximize UV protection.
  • Hydrate Well: Make sure you hydrate before you start. If you wait until you are thirsty, it probably too late. Keep your drinks cool and drinking a little bit often is better than a lot at once. If you are planning to participate in vigorous exercise, sports drinks can be helpful to replenish the minerals lost during sweat.

Recognize The Warning Signs

While exercising in warm weather is possible, you must be able to recognize the early signs of heat exhaustion to avoid serious complications. Heat exhaustion is the body’s response to an excessive loss of water and salt, usually through excessive sweating. It’s most likely to affect the elderly population and those working in hot environments but if left unmanaged can lead to a deadly condition known as heat stroke.

Heat Exhaustion

Heat exhaustion is the body’s response to an excessive loss of water and salt, usually through excessive sweating, and is most likely to affect the elderly and those who work in a hot environment.

Symptoms Include:

  • Headache
  • Nausea
  • Dizziness
  • Weakness
  • Irritability
  • Thirst
  • Heavy sweating
  • Elevated body temperature

Heat Stroke

Heat stroke is the most serious heat-related illness. It occurs when the body can no longer control its temperature: the body’s temperature rises rapidly the sweating mechanism fails and the body is unable to cool down. Heat stroke can cause permanent disability or death if the person does not receive emergency treatment.

Symptoms Include:

  • Confusion, altered mental status, slurred speech
  • Loss of consciousness
  • Hot, dry skin or profuse sweating
  • Seizures
  • Very high body temperature

If you or someone you know is experiencing symptoms of heat stroke, stop what you’re doing and call 911 Emergency Medical Services. Move the person away from direct heat if possible or to an air-conditioned room. Use water to cool the skin and apply wet cloths to aid in rapid cooling. Continue to monitor levels of consciousness until Emergency Medical Services arrive.


One of the keys to staying active in the heat is to maintain adequate levels of hydration. Many people believe that consuming water is enough to rehydrate and while it does help, studies have shown as much as 30% more fluid is consumed with flavored drinks compared to plain water. Flavored Carbohydrate-electrolyte drinks are more affective in promoting post-exercise rehydration than plain water or low electrolyte diet cola.

Many athletes do not consume enough sodium in their regular diet to support strenuous physical activity, especially in the early stages of training and in hot and/or humid environments. Having recovery drinks and food that contain sufficient levels of sodium is useful for a number of purposes:

  1. Replaces sodium lost in sweat
  2. Stimulates glucose (energy) absorption by the muscles
  3. Increases athletes’ drive to drink
  4. May reduce the symptoms of exertional heat cramps exertional heat exhaustion and exertional hyponatremia

Measuring Your Hydration Level

The easiest and most simple way to understand your current hydration level is by looking at the color of your urine. If you are light in color, you are generally well-hydrated. If your urine color is towards the darker end of the scale, be sure to supplement your intake with fluids and monitor the color over the next few hours. Continued signs of dehydration, even after consuming fluids may be an indication of a serious condition. Contact your nearest medical provider to avoid further complications.

Image showing Urine Color Chart

Use It or Lose It

In summary, don’t let the heat of the summer allow your level of fitness to decline. Without regular doses of exercise and activity, the body will decondition. Typically, cardiovascular fitness is reduced first, followed by muscular strength. As people become less fit and activity becomes harder, they do less, leading to further deconditioning and down into a vicious cycle. Deconditioning can also lead to more aches and pains, illness, and disease. It only takes two weeks without exercise to have a significant loss of cardiovascular fitness. Two to eight months of detraining can erase virtually all of your gains. If you need help with conditions that are preventing you from exercising, contact our team to get yourself back on track.