Interim NIOSH Training for Emergency Responders: Reducing Risks Associated with Long Work Hours

Protecting Yourself from Heat

Getting overheated increases fatigue and sleepiness as well as increases the risk for developing heat-related illnesses such as heat stroke, heat exhaustion, or heat cramps. Heat stroke can cause death or permanent disability.

  • Workers are at an increased risk of heat stress when wearing personal protective equipment (PPE), especially from wearing semipermeable (penetrable) or impermeable clothing, when the temperature exceeds 70°F, or while working at high energy levels. These types of clothing materials trap heat close to a worker’s body. Workers should be monitored by establishing a routine to periodically check heart rate, temperature, and other physiological signs of overexposure. (OSHA guidance, page 17, iconexternal icon)
  • A manager at the worksite who is well-informed about heat-related illness can modify work activities and the work/rest schedule as needed.
  • Workers who are not acclimated to working in the heat are at higher risk. A Cal/OSHA study in 2005 found 80% of the cases had only been on the job for four or fewer days ( icon). To help new workers and those returning to a job after time away build up a tolerance for hot conditions, gradually increase the workload or allow more frequent breaks.
  • Make sure that workers understand: 1) the signs and symptoms of heat-related illness; 2) importance of drinking water often and frequently resting in a cool environment; 3) steps if someone is having symptoms.
  • See OSHA’s guidance for scheduling work and rest periods when working in hot environments. icon
  • Rest periods to cool down and drink fluids can be productive times in a cooler environment. Workers may continue to perform mild or light work, such as completing paperwork or attending a meeting.
  • For information to prevent risks from heat, see OSHA’s “Water, Rest, Shade: The work can’t get done without them” ( icon) and the NIOSH heat stress and heat illnesses fact sheet (

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Page last reviewed: April 1, 2020