Heat Stress

The body is designed to maintain an internal temperature of approximately 98.6°F. Excessive heat is released by circulating blood to the capillaries in the upper layers of the skin thus increasing heat transfer and perspiration. When the body heats up faster than it can cool itself down, mild to severe heat-related illnesses may develop. Because hundreds of people die annually in this country from heat-related illnesses, it’s important to recognize the symptoms of heat-related illnesses and understand how to prevent, control, and respond to its effects.

The following warning signs are what to watch for and how to respond as the body temperature rises:

• 98.6°F - Normal body temperature.
• 102°F - Significant overheating begins.
  • Symptoms: Profuse sweating, muscle cramps, exhaustion, weak but rapid pulse, fast but shallow breathing.
  • What to do: Move to the shade, cool the body by fanning and spraying with a mist of cool water, drink cold non-alcoholic fluids.
• 106°F - Heat stroke occurs.
  • Symptoms: Throbbing headache, dizziness, nausea and vomiting, confusion, seizures, loss of consciousness.
  • What to do: Cover the body with wet sheets/ice packs, move to an air-conditioned area, and use a fan to cool.
• 108°F - Death is imminent.
  • Symptoms: Comatose or unresponsive, organ systems shut down, body cannot sustain normal processes.
  • What to do: Even aggressive medical attention may not help.

How heat-related illnesses can be prevented:

• Drink plenty of water, not caffeinated drinks or alcohol. Salt tablets should never be taken.
• Limit exposure time. Try to schedule jobs during the cooler part of the day.
• Gradually build a tolerance (called acclimatization) to working in the heat as the weather warms up or after employees have been away from the heat for a couple of weeks at a time.
• Have a “buddy system”—a fellow worker spotting the early signs of heat stress, such as irritability, confusion, or clumsiness in a co-worker.
• Wear loose-fitting, light-colored, lightweight clothing.

California is the first state to enact a heat-illness prevention standard, GISO §3395. The regulation requires employers to provide water, shade, and training on heat stress to all outdoor workers, including supervisors.

Fed/OSHA has a number of resources available on this topic, including a heat index tool, a heat safety tool smart phone app, and heat stress cards in English, Spanish, and Vietnamese.

Revised: 04/2017