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The Dangers of Heat Stress

Heat stress needs to be taken seriously. Working in a hot environment puts stress on the body’s cooling system. When heat is combined with other stresses like hard physical work, loss of fluids or fatigue – it may lead to heat-related illness, disability or even death!

The body is always generating heat and passing it to the environment. The harder you work the more heat your body has to lose. Heat leaves your body in several ways:

  • Transfer from skin to air
  • Evaporation by perspiration
  • Exhaling hot air
  • Touching a cool object

Individuals over age 40 need to take extra care when the weather is hot, because the ability to sweat declines as we age. However, heat stress can also affect individuals who are young and fit.

Water is crucial to helping the body adjust to high temperatures. The rate of water intake must equal the increased rate of water loss by perspiration to keep body temperature normal. When it’s hot, drink plenty of water! Your body must work even harder to get rid of excess heat when conditions are both hot and humid. Unfortunately, perspiration can’t evaporate as readily under muggy conditions. The process is easier if the surrounding air is moving. That’s why we welcome a cool breeze, or turn on a fan when the air is sticky.

Sickness and accident rates increase when heavy work is done at temperatures above 30 degrees. Don’t push yourself beyond your limits. It could be harmful to your health, and could put you at increased risk of having an accident.

Heat Stress Hazards

There are three common conditions that can result from the body overheating

  1. Heat Cramps: Heavy sweating drains the body of salt which cannot be replaced by simply drinking water. Painful cramps occur in the arms, legs or stomach while on the job, or later at home. Move to a cool area at once if cramping is experienced. Loosen clothing and drink cool, lightly salted water or a commercial fluid replacement beverage. Seek medical aid if the cramps are severe or don’t go away.
  2. Heat Exhaustion: Inadequate water and salt intake causes the body’s cooling system to break down. Symptoms include heavy sweating, cool, moist skin, body temperature over 38 degrees, weak pulse, and normal or low blood pressure. The victim is likely to be tired, weak, clumsy, upset, or confused. They will be very thirsty and will pant or breathe rapidly. Their vision may be blurred. Get medical help immediately! Heat exhaustion can lead to heat stroke, which can kill. Move the person to a cool, shaded area. Loosen or remove excess clothing. Provide cool, lightly salted water. Fan and spray the victim with cool water.
  3. Heat Stroke: Heat stroke can kill a person quickly! Once the body uses up all its water and salt, sweating ceases. Temperature can rise quickly. You can assume a person is suffering from heat stroke if their body temperature is over 41 degrees, and any of the following symptoms are present:
  • Weakness, confusion, distress, strange behavior
  • Hot, dry, red skin
  • Rapid pulse
  • Headache or dizziness
  • In later stages of heat stroke, a victim may pass out and have convulsions

Call an ambulance immediately if heat stroke is suspected. The victim’s life may be on the line! Until help arrives, move the victim to a cool area and remove excess clothing. Fan and spray them with cool water. Offer sips of water if the victim is conscious.

Heat Wave Guidelines

The following measures should help prevent the development of heat-related illness.

  1. Slow down in hot weather. Your body’s temperature regulating system faces a much greater workload when temperature and humidity are higher.
  2. Be mindful of early warnings of heat stress, such as headaches, heavy perspiration, high pulse rate and shallow breathing. Take a break immediately and get to a cooler location. Watch for heat stress signs among your co-workers.
  3. Dress for hot weather. Lightweight, light colored clothing reflects heat.
  4. Drink plenty of water, don’t let yourself “dry out”
  5. Increase your salt intake, preferably by adding salt to your food (consult your physician if you are on a salt-restricted diet)
  6. Try to get used to warm weather gradually. Take it easy for those first two or three hot days. Your body will have a better chance to adjust if you take it slow.
  7. Get out of the heat occasionally. Physical stress increases with time in hot weather. Take breaks in a cool, shady location.
  8. Don’t try to get a suntan while you are working! It’s harder for your internal cooling system to work through sunburned skin. Wear a hat and long-sleeved shirt to prevent burning (which we know can increase the risk of skin cancer).

Finally, let’s take a moment to review some of the “do’s and don’ts” of preventing heat related illnesses.


  • Drink plenty of water
  • Take breaks in a cool, shady environment
  • Watch for symptoms of heat stress


  • Try to get a suntan while working
  • Try to “keep up” with the rest of the crew when you feel ill
  • Ignore symptoms of heat stress