Menu Close

Preventing Injuries and Illness Related to Extreme Heat and Weather


Preventing Injuries and Illness Related to Extreme Heat and Weather

Your body has a natural cooling system. It is always working to maintain a safe temperature. Sweating helps your body cool down.

When you exercise in the heat, your cooling system has to work harder. Your body sends more blood to your skin and away from your muscles. This increases your heart rate. You sweat a lot, losing fluids in your body. If it is humid, sweat stays on your skin, which makes it hard for your body to cool itself.

Athletes are especially prone to heat exhaustion and other heat illness, such as heat stroke, heat cramps, and dehydration, when exercising in hot and humid conditions.

Taking precautions and recognizing the symptoms or early warning signs of heat exhaustion is essential if you exercise in hot weather.

What is Hyperthermia?

Hyperthermia is overheating of the body due to excessive exposure to high heat and humidity. Humidity is the amount of moisture in the air. High temps (80+ degrees ) and high humidity (75+%) can cause heat stress.

The body must be able to dissipate heat, and its primary method of doing this is through the evaporation of sweat.  For the body to cool, air must be cooler than the body. At 65% humidity, evaporation slows; at 75% humidity, evaporation stops.  65% of body heat is lost through the head and neck. If the body is dehydrated, it cannot dissipate heat with sweat, and become overheated. Devices such as the “cool suits” or “cool vests” worn underpads and hooked into a sideline cooling unit operate under the principle that increased evaporation of sweat serves to cool the body more rapidly.  The Cool Zone sideline fans seen at many sporting events emit a cool mist to perform essentially the same function via fast-moving cool moist air.

How to recognize that you are dehydrated?

As noted above, sweating dissipates heat but also causes the body to lose electrolytes (sodium, chloride, potassium, magnesium, calcium).   A 2% loss of body weight through sweating (i.e. 3 pounds in a 150-pound person) can impair the performance, and increase the chance of heat illness. Sweat that tastes salty or burns the eyes is a sign of significant loss of sodium, and it must be replaced.  Sports drinks such as Gatorade are effective because they contain a proper balance of electrolytes and sugar, and are beneficial during both endurance activities and short-term high-intensity activities.

Pre-hydration (2-3 hours before activity) with a sports drink containing electrolytes is effective at preventing dehydration because the increased sodium allows the body to retain fluid longer than drinking water alone. Drinking water alone turns on the kidneys prematurely and increases the need to urinate.  Sports drinks and/or water should be consumed cold (approx. 50 degrees), because colder fluids absorb faster and decrease the body’s core temperature.

Thirst is an initial sign the body is already slightly dehydrated. Other signs of advancing dehydration include dry mouth, headache, dizziness. irritability, and fatigue.

Common Heat Illness

The risk of heat-related illnesses increases when the air temperature and humidity are high and the sun is bright and direct.  A fitness professional should be able to differentiate between cramps, syncope (fainting), exhaustion and stroke.

Heat Syncope

Is a mild form of heat illness characterized by dizziness, collapse or fainting. It occurs when blood vessels dilate or blood pools in the legs or arms.  Persons suffering from heat syncope should lay down in a cool area and replace fluids.

Heat Cramps

A painful muscle cramp in arms, legs, or abdomen is often caused by overwork, prolonged sweating, or not being acclimated to heat.  Treat heat cramps increase through water and electrolyte (particularly sodium) intake and resting in a cool area. In the case of persistent cramping, direct compression and/or ice massage of the muscle can be utilized.  Additionally, reciprocal inhibition innervation (isometrically contracting the opposite muscle group) may prove effective. Persons suffering heat cramps are often unable to return to activity the same day, as the cramps are likely to reoccur.

Heat Exhaustion

A moderate form of heat illness categorized as mild hyperthermia (body core temp less than 104 degrees).  Most signs of heat exhaustion can be recognized and acted upon before the condition becomes more serious.  Signs of heat exhaustion include:

  • dry tongue and mouth
  • profuse sweating
  • fatigue/weakness/dizziness
  • mental dullness
  • loss of coordination
  • stomach and/or muscle cramps
  • nausea or vomiting
  • headache
  • pale skin
  • rapid pulse

Treatment consists of replacing or intravenously administering fluids, placing the person in a cool environment, and applying a sponge with cool water, especially to the head and neck.

Heat Stroke

A severe form of heat illness in which the body’s thermoregulatory mechanism breaks down due to excessive core temperature; it is a life-threatening emergency that may lead to brain damage or death.  Many signs of impending heat stroke appear prior to the actual occurrence of heat stroke; those signs include:

  • headache
  • dizziness
  • diarrhea
  • vomiting
  • cessation of sweating (occurs in roughly 25% of heat stroke cases)
  • confusion or irrational behavior
  • sudden collapse with loss of consciousness
  • flushed hot skin
  • rapid, strong pulse (160-180 bpm)  
  • rectal temperature of 104 degrees or higher (107 degrees = death)
  • increased/shallow respirations

Treatment of heat stroke requires promptly decreasing the body temperature within 45 minutes.  Effective treatments are immersion in an ice bath, or use of a sponge with ice water and fan, followed by transport to an emergency room.  

Tips for Exercising Outdoors in the Heat

Monitor Dehydration and Fluid Replacement

For extreme exercisers, it’s important to monitor dehydration. Drink 2 cups of water 2 hours before going outside to exercise and sip about 4oz of water every 15 – 20 minutes while outdoors to prevent muscle fatigue and heat exhaustion. Fluids should be easily accessible before, during and after activity. Drink 7-10 ounces of cold water and/or a 6% glucose solution sports drink every 15 minutes to compensate for sweat loss.

Gradual Acclimatization

Progressively train/exercise to acclimate to hot weather.  A person can expect to achieve 80% acclimatization in 5-6 days, with 2 hours of activity in morning and 2 hours in afternoon. 100% acclimatization will take 10-14 days. Most heat-related illnesses occur during the first few days of training. Fitness professionals must monitor temperature and humidity readings and provide adequate rest periods in a cool, shaded area.

Identifying Susceptible Individuals – individuals typically more susceptible to heat illness include:

  • those with greater muscle mass
  • overweight individuals
  • those with poor fitness levels
  • excessive sweaters
  • people that don’t dissipate heat well (including carriers of sickle cell trait)
  • those with a history of heat illness
  • those with a poor diet
  • persons with an infection, fever, gastrointestinal condition, or diarrhea

Keep Weight Records

Weigh the person before and after activity for the first two weeks of training or activity. A loss of 3% – 5% of your body weight is extremely dangerous because blood volume is decreased. A well-balanced diet is a must.

Choose Your Workout Time Wisely

Exercise before 10 am or after 7 pm, when the day’s heat isn’t at its peak.

Wear Appropriate Clothing and Protect your skin

Choose light loose fabrics that wick sweat away from the body. Wear a hat to keep the sun off your face and the sweat out of your eyes. Use a sweat-resistant sunscreen designed to use for outdoor sports. Make sure to reapply accordingly. Wear sunglasses to protect your eyes from the sun.

Seek Shade

Go for a hike, trail run or walk in the shady woods or a bike ride along a breezy beach where the temperature is often 10 degrees cooler. Bootcamp-style exercises can be done in a shady spot for some heat relief.

Pay Attention to Your Body

Lower intensity on days of extreme heat and/or humidity and stop exercising if you feel dizzy, have chills, are nauseous or light-headed. These are possible signs of heat exhaustion.

Learn More

Check out what it takes to start a career in personal fitness training. This is your most affordable and fastest way to become a highly qualified personal trainer.

Is your recertification coming up? Learn more about earning your CEU credits. You can find the full list of CEU courses here.

One of the most popular and fastest ways to get started working with clients while you travel is to coach/train online. You will want to learn more about GymGo. GymGo lets you work with clients and make money in different ways: online, live-streaming virtual training & on-demand training. Use our link to get yourself a free 14-day trial >>>

If you are ready to start your online personal training or coaching business, don’t forget to learn more about our online coaching course. You will also really enjoy this very comprehensive training course called Online Expert Empire.

There is always something exciting about earning a new training or coaching certification and applying that new knowledge of how you train your clients. This also helps you hit the reset button.

NESTA and Spencer Institute coaching programs are open to anyone with a desire to learn and help others. There are no prerequisites.

That’s it for now.

Take action!

NESTA | Spencer Institute

PS: Click here to see many helpful business/career resources

NESTA Pinterest