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Preventing and Responding to Heat Illness

Best Practises - Your Written Program

I. Effective Work Practices

4. Preventative Recovery Periods

Men taking a break under a tree - shaded area

A Preventative Recovery Period means a period of time to recover from the heat in order to prevent heat illness. Providing cooling (see Provide Cooling from Shade and Provide Cooling Using Alternative Measures) by resting in adequate shade or using alternative measures (which have been demonstrated to be equally effective) allows the body’s internal temperature to come closer to the "normal range" (i.e., within a very narrow temperature range above or below 98.2 °F). Also, as the body cools heart rate and respiration slow down.

Access to Shade - Employees suffering from heat illness or believing a preventative recovery period is needed, shall be provided access to an area with shade that is either open to the air or provided with ventilation or cooling for a period of no less than five minutes. Such access to shade shall be permitted at all times. Except for employers in the agriculture industry, cooling measures other than shade (e.g., use of misting machines) may be provided in lieu of shade if the employer can demonstrate that these measures are at least as effective as shade in allowing employees to cool. See Provide Cooling Using Alternative Measures.


Because of extreme environmental conditions during a heat wave, the risk of developing heat illness is greater. Employees’ physical and mental condition can change rapidly into a serious medical condition. Therefore, during a heat wave employees should be encouraged not to discount any discomfort or symptoms they are experiencing. They should immediately report any problems they are experiencing to a supervisor and coworker.


A Preventative Recovery Period is not a substitute for the treatment of heat illness by medical personnel. The progression to serious heat illness can be rapid. Even the initial symptoms may indicate serious heat exposure. Therefore, if any of the signs and symptoms of heat illness (e.g., headache, muscle cramps, fatigue, fainting, seizures, unusual behavior, nausea or vomiting, hot dry skin, or unusually profuse sweating) are recognized, worksite first aid procedures should be initiated by a trained and certified first aid provider followed immediately by emergency response procedures as indicated by first aid assessment.

Smart Tips

Provide Preventative Recovery Periods

  • Train your employees and supervisors so they understand the importance of Preventative Recovery Periods in preventing heat illness
  • Train your employees and supervisors on your Emergency Response Procedures
  • Have supervisors and /or other designated person(s) closely monitor the victim(s) during Preventative Recovery Periods
  • Ensure that employees recognized as having any of the symptoms of heat illness are never left alone or sent home without medical authorization
  • Ensure employees frequently drink sufficient amounts of water
  • Provide locations for PRPs which are:
    • Available to all employees and supervisors at all times
    • Spacious enough to accommodate workers in a relaxed body posture
    • In the shade and are either open to the air or provided with ventilation or cooling
    • Near sufficient supplies of drinking water