June 2009 Safety Tip


Here in Maricopa County, a lot of us spend many hours outdoors. Sometimes for work and sometimes for pleasure. It is important to understand that heat can be very dangerous.

One effect of high heat is Heat Stress. Here are somethings you should know about Heat Stress.

What it is

Heat Stress is the inability of the body to cool itself down when its internal temperature rises above 98.6 degrees Fahrenheit.

There are four common forms of heat stress:

  • Heat Fatigue, which occurs when the body is straining under a tough workload in hot conditions.
  • Heat Cramps, which occur when people continue to work in hot conditions without resting.
  • Heat Exhaustion and Heat Stroke occur when people lose a significant amount of body fluids. Heat exhaustion and stroke involve symptoms consistent with severe confusion, rapid pulse, upset stomach, or fainting. Heat exhaustion and heat stroke represent life threatening conditions if not dealt with immediately.

According to the City of Phoenix Fire Department,

  • Hot weather triggers a variety of medical emergencies, even healthy people should take it easy
  • Those with respiratory and other health problems must be especially careful.
  • Stay out of the sun as much as possible.
  • Drink extra fluids, but avoid alcoholic beverages which can cause dehydration. The best ways to prevent a sun stress emergency are to drink before you're thirsty and drink often.
  • Eat a healthy diet.
  • Wear a hat or cap, keep the neck covered and wear loose fitting clothing.
  • If you can, work in the cool hours of the day or evening.

The greatest amount of heat loss from the body occurs at the head. This is why it is important to wear a hat or cap in the sun.

Heat Stress is the result of the body losing moisture AND electrolytes due to sweating which results in the build up of excess salt. Sweating is the body's natural means for keeping cool. Electrolytes are crucial for the proper functioning of the body. Thus the use of table salt or salt tablets to replace body electrolytes is no longer recommended. There are many electrolyte replacement drinks are available on the market.

The OSHA Technical Manual (TED 1-0.15A), Section III - Chapter 4 (January 20, 1999, 19 pages) is an excellent place to start if you are unfamiliar with heat stress. This document contains useful sections on the signs and symptoms of heat stress, sampling methods, control suggestions, and guidelines for investigating heat stress in the workplace.

A web-based PowerPoint presentation for HEAT STRESS in PDF format, prepared by the International Union of Operating Engineers and the US Department of Energy's jointly operated "International Environmental Technology and Training Center" in Beaver, WV, is another source for information. Although it is designed to address workers involved in hazardous waste operations, the information in general can be applied to everyone in an easy-to-read format.

What you should do

Here is what you should do if you suspect someone is suffering from Heat Exhaustion:

  • Call for medical help immediately!
  • Move the person out of the heat
  • Remove any protective clothing and loosen restrictive clothing
  • Cool the person down
  • Do not provide any fluids until the person is conscious.

Things to remember

The five important things to remember about Heat Stress:

  • Heat Stress can strike at any time
  • Heat Stress illness can range from fatigue to death
  • Heat Stress results when the body’s cooling system cannot keep up with the body’s rising temperature
  • Know the signs and symptoms of heat stress
  • When heat stress symptoms appear, take immediate corrective actions

For additional information or a video on Heat Stress contact the Maricopa County Risk Management Safety Office at (602) 506-8601.