Protect Against Heat-Related Illnesses

June 10, 2019 | Abby Caviness

Soaking up the summer sun is all fun and games until the intense heat ruins your fitness plans. While breaking a sweat on a hot day may be an appealing thought, heat-related illnesses are far less appealing. However, there are several ways to stay cool and keep your internal body temperature low, so you can keep training.* USHEALTH Group® wants to help you understand the risks of heat-related illnesses and how to prevent a potentially fatal situation.

Heat-Related Illnesses

According to WebMD, heat-related illnesses occur when your body sends blood to the surface of your skin to cool itself, leaving your brain, muscles and other organs with less blood.1 So, when you are running outside on a hot day and your blood suddenly leaves your muscles, your workout can take an unexpected and harmful turn. This lack of blood can interfere with your physical strength and mental capacity, which can lead to serious problems. While none of these heat-related illnesses correspond directly with exercising outside and can occur just by being in a hot environment, the physical exertion of fitness activities can accelerate the process of overheating.

Hyperthermia refers to the three heat-related conditions characterized by high body temperature caused by external factors.2 For hyperthermia to occur, a person must have a body temperature of more than 100.4°F.

These conditions occur in stages and vary in severity. In fact, each stage has its own set of symptoms and at its most severe stage, can cause death if not properly treated.

Heat Fatigue and Cramps

This is the first and least severe stage of hyperthermia and can be categorized by the following symptoms:2

  • Excessive sweating
  • Exhaustion
  • Flushed or red skin
  • Muscle cramps, spasms, and pain
  • Headache or mild light-headedness
  • Nausea
Heat Exhaustion

Heat exhaustion is the second stage of hyperthermia and, if left untreated, can lead to heat stroke, which is a life-threatening condition. Symptoms include:2

  • Cold, pale, wet skin
  • Extreme or heavy sweating
  • Fast but weak pulse
  • Nausea, vomiting, and diarrhea
  • Headache
  • Muscle cramps
  • Exhaustion
  • Weakness
  • Intense thirst
  • Dizziness
  • Less frequent urination and dark urine
  • Difficulty paying attention or concentrating
  • Mild swelling of the feet and ankles or fingers and hands
  • Temporarily fainting or losing consciousness
Heat Stroke

Heat stroke is the most severe stage of hyperthermia and can have dangerous consequences if not treated.  At this stage, the internal body temperature is above 103°F. People with heat-related, heart and blood pressure conditions are more likely to be affected by hyperthermia, and those with a compromised immune system are more in danger of complications.

While many of the early signs of heat stroke are the same as those for heat exhaustion, there are a few telltale signs of this serious issue, such as:2

  • Fast, strong pulse or very weak pulse
  • Fast, deep breathing
  • Reduced sweating
  • Hot, red, wet, or dry skin
  • Nausea, headache, dizziness
  • Confusion and disorientation
  • Blurred vision
  • Irritability or mood swings
  • Lack of coordination
  • Fainting or losing consciousness

In the case of a severe heat stroke, complications include:

  • Seizure
  • Organ Failure
  • Coma
  • Death

As you can see, the consequences of too much sun and not giving your body what it needs can lead to extremely severe consequences. Thankfully, there are several ways to prevent these conditions from affecting you.

Avoiding Heat-Related Illnesses

It is unrealistic to try and avoid the summer heat all the time, because having fun in the sun is important for your emotional wellbeing. However, when it comes to exercise, there are a few precautionary measures you should take to protect yourself. For example:3

Watch the temperature

Start paying attention to weather forecasts and heat alerts for when you are planning on being outdoors. If you see an potentially dangerous temperature reading, avoid exercising outside and look for alternative locations and activities.

Get acclimated

If you are used to being inside in a cool environment, take your time incorporating outdoor exercise. Keep in mind it takes one to two weeks to adapt to the summer heat.

Know your fitness level

If you have just started exercising, your level of endurance is lower than that of someone who is consistently active. Be sure to take frequent breaks and reduce your intensity when your body tells you to.

Drink plenty of fluids

A key ingredient for heat-related illnesses is dehydration. Keeping hydrated can replenish the fluids in your body you lose through sweating. In addition, if you plan on an intense workout, sports drinks can also be incorporated to replenish the chloride and potassium you also lose through sweating.

Dress appropriately

Wearing loose-fitting and lightweight clothing can help to keep you cool in the summer heat. In addition, avoid darker colors and wear a hat with a brim to shade you from the sun.

Woman applies sunscreen to aid against heat-related illnesses.
Wear sunscreen

Along with the heat, the sun’s rays can also burn and damage your skin. When you have a sunburn, your body is less able to cool itself down and you have an increased risk of skin cancer.

Have a backup plan

When it comes time to work out and you see the weather is hazardous for outdoor activity, be sure you have a backup activity ready indoors. Whether you go to the gym or form a workout plan in your home, make sure you do not push yourself, and listen to the weather to know when it is too hot to be outside.

Avoid midday sun

The heat from the sun peaks at midday, so moving your exercise time to the morning or night will help you avoid the highest temperatures. However, if you need to exercise during this time, try finding a shady area or working out in a swimming pool.

Understand your medical risks

Certain individuals have an increased risk of heat-related illnesses, such as people who have heart conditions, compromised immune systems, and people over the age of 65. Additionally, certain medications can increase your risk. Be sure to contact your doctor if you plan to exercise in the heat and have health conditions which may put you at risk.

Fitness Couple Taking a Short Break after Jogging with an Energy Drink to aid against heat-related illnesses.


Exercising in the heat and ignoring the warning signs of a heat-related illness can be potentially fatal. Therefore, it is important to stay informed of the risks and educate yourself about ways to prevent this from happening to you. Exercise is good for you but can be dangerous if you are not careful. We want you to be healthy, but it is more important for you to be safe.

*This material is provided by USHEALTH Group for informational/educational purposes only and should not replace medical/clinical advice or direction from your health care provider.

  1. Felson, Sabrina, “The Basics of Heat-Related Illness,”, last modified July 20, 2017,
  2. Huizen, Jennifer, “What should you know about hyperthermia?”, last modified December 5, 2017,
  3. Mayo Clinic Staff, “Heat and exercise: Keeping cool in hot weather,”, May 6, 2017,
By |2019-09-23T11:32:33-05:00June 10th, 2019|Categories: Fitness|Tags: , |0 Comments