What Is Heat Stress?

Working muscles need a greater blood flow to cool the body. The body needs to shift blood away from muscles to assure an ideal sweat rate and to cool the blood. Dehydration can cause low blood volume, which can lower the body’s ability to cool the blood, leading to confusion, fatigue and potentially, heat illness.

Dry Clothes and Skin Don’t Mean You Aren’t Sweating!

You may not feel wet or sticky in dryer climates, but you are still sweating. You can lose as much as 68 ounces (half a gallon) of fluid on a very warm day. Fainting (heat syncope) may be a problem for workers who simply stand still in the heat when they are not acclimated to a hot environment. Victims usually recover quickly after lying down for a brief period. Moving around, rather than standing still, usually reduces the possibility of fainting.

Symptoms of Heat Exhaustion

  • Headaches, dizziness, lightheadedness or fainting.
  • Weakness and moist skin.
  • Mood changes such as irritability or confusion.
  • Upset stomach or vomiting.

Symptoms of Heat Stroke

  • Dry, hot skin with no sweating.
  • Mental confusion or losing consciousness.
  • Seizures or convulsions.

Ways to Prevent Heat Stress

  • Hydrating before work activity is crucial. Consume water or an electrolyte beverage 24 hours prior to activity.
  • Drink 16 ounces of water two-three hours before work activity.
  • Drink water frequently (every 15-30 minutes, drink six-12 ounces)
  • Most people consume enough salt in their diets. Salt tablets are NOT necessary for general use.
  • Post work activity – drink 16 ounces of water for every pound of weight loss.
  • Take breaks and move a person showing symptoms of heat stress away from heat sources or direct sunlight.
  • Utilize ventilation or fans in enclosed areas.
  • It takes one-two weeks for the body to adjust to higher temperatures. This adaptation to heat can be quickly lost, so your body will have to adjust after a vacation.
  • Avoid caffeine (makes the body lose water and increases the risk for heat illness).
  • Avoid alcohol consumption. Many cases of heat stroke have occurred the day after heavy drinking.
  • Wear light-colored, cotton clothes, and keep your shirt on.

What to Do for Heat-Related Illness

  1. Call 911 at once if a worker exhibits heat stroke symptoms.
  2. Move the worker to a cool, shaded area.
  3. Loosen or remove heavy clothing.
  4. Provide cool drinking water.
  5. Fan and mist the person with water.

Download the printable PDF and Recording Form here.

Members can download the audio version of this toolbox talk here.

Heat Stress

Originally published 7/18/2017

Working in a hot environment, such as a construction site, puts stress on the body’s cooling system. When heat is combined with other work stresses – like hard physical labor, loss of fluids, or fatigue – it may lead to heat-related illness, disability or even death. There are three stages to heat-related illness: heat cramps, heat exhaustion and heat stroke.

Heat cramps are painful, brief muscle cramps that are brought on because the body has lost minerals through sweating. If cramping occurs, move to a cool area at once. Loosen clothing and drink cool water or an electrolyte replacement beverage. Seek medical aid if the cramps are severe, or don’t go away.

Heat exhaustion can occur after you’ve been exposed to high temperatures for several days and have become dehydrated. Symptoms include confusion, dizziness, headache, fatigue and sometimes nausea. Without proper intervention, heat exhaustion can progress to heat stroke. If you experience heat exhaustion, get out of the heat immediately and rest, preferably in an air-conditioned environment. If you can’t get inside, try to find the nearest cool and shady place. Slowly drink fluids. If possible, lie down with your feet and legs slightly elevated.

Heat stroke is the most serious form of heat illness and is a medical emergency. It often occurs after heat cramps or heat exhaustion are not properly cared for. But it can strike even if you have no previous signs of heat illness.

Heat stroke can kill, or cause damage to the brain and other internal organs. Symptoms are similar to heat exhaustion, but the skin is hot and dry and breathing is deep and fast. The victim may collapse. The body is no longer able to sweat, and the body temperature rises dangerously. If you suspect that someone is a victim of heat stroke – also known as sun stroke – call 911 immediately. Move the victim to a cool area and remove excess clothing while waiting on help to arrive. Fan and spray them with cool water. Offer sips of water if the victim is conscious.

There are things you can do to prevent heat-related illnesses.

  • Drink plenty of fluids. Consider beverages that replace electrolytes. Stay away from beverages with caffeine. Caffeine contributes to dehydration.
  • Slow down in hot weather. Your body’s temperature-regulating system faces a much greater workload when the temperature and humidity are high.
  • If possible, get accustomed to the heat gradually.
  • Dress for hot weather. Light colored clothing reflects heat.
  • Get out of the heat occasionally. Take breaks in a cool, shady location.
  • Eat light, cool meals.

Download the recording form here.