Heat Stress

Students, faculty, and staff who are exposed to excessive heat or who work in hot environments may be at risk of heat stress. Various factors can contribute to heat stress such as air temperature, physical activity, individual susceptibility, radiant heat, humidity, air flow, and clothing type. Heat stress can result in heat stroke, heat exhaustion, heat cramps, or heat rashes.

Heat Stress Recognition and Mitigation SOP

Certain behaviors also put people at greater risk: drinking alcohol, taking part in strenuous outdoor physical activities in hot weather, and taking medications that impair the body’s ability to regulate its temperature or that inhibit perspiration. Heat stress can be induced by high temperatures, heavy workloads, and clothing inappropriate for the heat and humidity.

It often takes two to three weeks for humans to become acclimated to a hot environment. This acclimation can subsequently be lost in only a few days away from the heat. As a result, humans should be more cautious about heat stress during large temperature swings, during the season’s first heat wave after coming back from a vacation, or when beginning a new job. In short, precautions should be taken anytime temperatures are elevated and the job is physically demanding.

Contact EHS, 512-471-3511 with any questions or concerns regarding heat stress.

Control of Heat Stress

Employers should reduce workplace heat stress by implementing engineering and work practice controls.

Engineering controls might include those that:

  • Increase air velocity.
  • Use reflective or heat-absorbing shielding or barriers.
  • Reduce steam leaks, wet floors, or humidity.

Work practice recommendations include the following:

  • Limit time in the heat and/or increase recovery time spent in a cool environment.
  • Reduce the metabolic demands of the job.
  • Use special tools (i.e., tools intended to minimize manual strain).
  • Increase the number of workers per task.
  • Train supervisors and workers about heat stress.
  • Implement a buddy system where workers observe each other for signs of heat intolerance.
  • Require workers to conduct self-monitoring and create a work group (i.e., workers, a qualified healthcare provider, and a safety manager) to make decisions on self-monitoring options and standard operating procedures.
  • Provide adequate amounts of cool, potable water near the work area and encourage workers to drink frequently.
  • Implement a heat alert program whenever the weather service forecasts that a heat wave is likely to occur.
  • Institute a heat acclimatization plan and increase physical fitness.


Train workers before hot outdoor work begins. Tailor training to cover worksite-specific conditions.

Employers should provide a heat stress training program for all workers and supervisors about the following:

  • Recognition of the signs and symptoms of heat-related illnesses and administra­tion of first aid.
  • Causes of heat-related illnesses and the procedures that will mini­mize the risk, such as drinking enough water and monitoring the color and amount of urine output.
  • Proper care and use of heat-protective clothing and equipment and the added heat load caused by exertion, clothing, and per­sonal protective equipment.
  • Effects of nonoccupational factors (drugs, alcohol, obesity, etc.) on tolerance to occupational heat stress.
  • The importance of acclimatization.
  • The importance of immediately reporting to the supervisor any symptoms or signs of heat-related illness in themselves or in coworkers.
  • Procedures for responding to symptoms of possible heat-related illness and for contacting emergency medical ser­vices.

In addition, supervisors should be trained on the following:

  • How to implement appropriate acclimatization.
  • What procedures to follow when a worker has symptoms consistent with heat-related illness, including emergency response procedures.
  • How to monitor weather reports.
  • How to respond to hot weather advisories.
  • How to monitor and encourage adequate fluid intake and rest breaks.


NIOSH Occupational Exposure to Heat and Hot Environments

NIOSH Acclimatization Fact Sheet

NIOSH Hydration Fact Sheet

NIOSH Work/Rest Schedules Fact Sheet