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Heat index, Heat stress and Heat illness…what you need to know!

The Hot days of summer were upon us! Don't worry... they will be back!

As a native your one to understand how these heat waves can affect you. Did you know in 2005 the California Assembly enacted a piece of legislation designed to protect employees in the work place called “The Heat Illness Prevention Plan” Workers who are exposed to extreme heat or work in hot environments may be at risk of heat stress. Exposure to extreme heat can result in occupational illnesses and injuries. Heat stress can result in heat stroke, heat exhaustion, heat cramps, or heat rashes. Heat can also increase the risk of injuries in workers as it may result in sweaty palms, fogged-up safety glasses, and dizziness. Burns may also occur as a result of accidental contact with hot surfaces or steam.

Workers at risk of heat stress include outdoor workers and workers in hot environments such as firefighters, bakery workers, farmers, construction workers, miners, boiler room workers, factory workers, and others. Workers at greater risk of heat stress include those who are 65 years of age or older, are overweight, have heart disease or high blood pressure, or take medications that may be affected by extreme heat.

Prevention of heat stress in workers is important. Employers should provide training to workers so they understand what heat stress is, how it affects their health and safety, and how it can be prevented.

So what about those who are involved in other activities?

The National Oceanic and Atmospheric Administration (NOAA) has developed a heat index chart parents, coaches and employees can use to determine when heat and humidity have reached the point where athletes and workers are at serious risk of heat illnesses, such as heat cramps, heat exhaustion or even heat stroke.

Before getting ahead of ourselves let me explain what these terms mean:

Heat illness: is a spectrum of disorders due to environmental exposure to heat. It includes minor conditions such as heat cramps, heat syncope, and heat exhaustion as well as the more severe condition known as heat stroke.

Heat cramps: Muscle pains that happen during heavy exercise in hot weather.

Heat exhaustion: Can be a precursor of heatstroke; the symptoms include heavy sweating, rapid breathing and a fast, weak pulse.

Heat stroke: Defined by a body temperature of greater than 40 °C (104 °F) due to environmental heat exposure with lack of thermoregulation. Symptoms include dry skin, rapid, strong pulse and dizziness, most of the time this is considered a life threatening situation.

Thermoregulation: the ability of the body to keep its temperature within certain boundaries, even when the surrounding temperature is very different.

National Oceanic and Atmospheric Administration ("NOAA") Heat Index

This heat index chart is designed to provide general guidelines for assessing the potential severity of heat stress.

Individual reactions to heat will vary. In addition, studies indicate that the susceptibility to heat disorders tends to increase with age. Exposure to full sunshine can increase Heat Index values by up to 15° F.

How to use Heat Index:

  1. Locate on the chart above the current Air Temperature down left side

  2. Locate the current Relative Humidity across the top

  3. Follow across and down to find Apparent Temperature (what it feels like to the body)

  4. Determine heat stress risk on chart below

Heat Illness Risk

Note: All of the information in this article is available in a helpful iPhone application called iHydrate TM, which calculates the heat index at your location and provides the heat illness risk.

To be safe your best bet is to consult with experts that will help you identify common problems and make suggestions for change before it's too late. C & A Safety Consultants has over 30 years experience in working with business, government agencies, schools, churches, and youth groups, camps (day and sleep away). Group CPR and safety classes are available too.

C & A Safety Consultants is located in Southern California.

C & A Safety can be reached at: or by telephone: 805-750-0915

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