Heat Stress: Overview
Understanding heat stress allows you to stay safe while working in hot environments.
Things you need to know:
- Heat exposure can cause a range of effects on your body, from irritating rashes to heat stroke, which is often fatal.
- Heat exposure can cause confusion and poor judgment—use the buddy system to monitor co-workers for symptoms of heat illness.
- Fatigue, heat exposure on recent previous days, certain medications and health conditions, age over 60 years, protective gear such as respirators or chemical-resistant apparel, recent illness, and intense exertion each increase the risk of getting heat illness.
- Drinking enough water is critical to preventing heat illness. Stay hydrated.
- Heat tolerance—but not the need for water—can be improved through gradual exposure (also called acclimatization).
Types of Heat Illness
Heat rash/"prickly heat"
Cluster of red bumps, pimples, or small blisters, usually on neck, upper chest, groin, under breasts, and in elbow creases
Muscle cramps, pain, or spasms in the abdomen, arms, or legs
Heat syncope (fainting)
Dizziness, light-headedness, or brief loss of consciousness during prolonged standing or suddenly rising from a sitting or lying position
Goose flesh or heavy sweating (Note: these symptoms may not always be present.)
Elevated body temperature, decreased urine output
Confusion, altered mental status, slurred speech, loss of consciousness
Hot, dry skin or profuse sweating
Very high body temperature
Fatal if treatment delayed
Factors that Increase Heat Illness Risk
- High humidity
- No wind or breeze
- Lack of acclimatization
- Physically demanding work
- Protective gear, including non-breathable or minimally breathable clothing, respirators, or chemical-resistant apparel
- History of previous heat illness
- History of recent illness unrelated to heat (especially involving vomiting or diarrhea)
- Recent alcohol use (within previous 24 hours)
- Certain health conditions
- Certain medications
- Age over 60 years
Workers need to look out for each other!
Use a buddy system!
Often it is a coworker who first notices signs of heat stress in another employee.
Points to Remember
Hot environments can be hazardous!
Acclimatization is critical, and may need to be repeated!
Give your body time to cool off. Pay attention to work/rest schedules!
Case Study: Heat Illness and Heavy Machinery
A 48-year-old employee was running a loader at an open pit mine in Arizona in mid-August when another employee noticed he was just sitting in the cab and not moving. A supervisor called the employee on the radio three times with no response. The supervisor went to the employee and discovered him to be confused and unresponsive.
More than just a health issue!
What might have happened if the employee had been driving or operating the loader when he became unresponsive?
- Page last reviewed: 9/23/2016
- Page last updated: 9/23/2016
- Content source: National Institute for Occupational Safety and Health, Mining Program