How to Manage Occupational Heat-Related Illnesses

Read this list of the top five heat-related illnesses in construction, including how to avoid them if you can and resolve them if you can't.
By Deepa Rajakrishnan
May 17, 2023

The warm seasons are typically the busiest months for commercial construction. But with the warm seasons comes the risk of heat-related illnesses, which can have a detrimental effect on employee health and safety. Heat-related illnesses can cause serious health problems and, in some cases, hospitalization or death. From a business standpoint, the costs associated with occupational heat-related illnesses can be significant, affecting both work productivity and, ultimately, a company’s bottom line. But there are some key strategies and tactics business leaders can implement to protect their workforces from the dangers of excessive indoor and outdoor heat.


To better understand the risks and effects of working in hot conditions, it’s helpful to understand how heat affects the human body. When a person is exposed to excessive heat, the internal mechanism that controls body temperature can start to break down. The body’s response to overheating is evaporative cooling—or sweating. But in humid conditions, sweating becomes a less effective method of regulating body temperature. As the body continues to lose heat, the effects of overexposure to excessive heat can start to manifest. The physical demands of a job can increase an employee’s internal heat load and cause overexposure. Even an employee’s personal protective equipment (PPE) can increase the internal heat load and cause overexposure to heat. Signs and symptoms of excessive heat exposure can include:

  • Dizziness
  • Nausea
  • Weakness
  • Irritability
  • Profuse sweating

These signs and symptoms could signal the onset of a heat-related illness. Some heat-related conditions are mild and can be treated onsite; others are severe and require emergency medical attention.


The five most common heat-related illnesses in construction are heat rash, heat cramps, heat syncope, heat exhaustion and heat stroke.

  1. Heat Rash: Heat rash is a skin irritation resulting from excessive sweating, especially when exposed to hot, humid conditions for prolonged periods. To treat this condition, the employee should keep the affected area dry and wear breathable fabrics (e.g., cotton, linen).
  2. Heat Cramps: Heat cramps can result from fluid or salt depletion after rigorous physical activity in a hot environment. To treat, the employee should replenish the body with salty foods and water or electrolytes, which are commonly found in sports drinks. Salt tablets are not recommended.
  3. Heat Syncope: Heat syncope is a collapsing or fainting episode that can occur if the body doesn’t acclimate to extreme heat. Because the body is struggling to cool itself, inadequate fluid replacement may cause dehydration. The condition will usually resolve after a period of rehydration and rest. The employee should also be instructed to lie flat (on one’s back) and elevate the feet, and emergency medical attention could be called if deemed necessary.
  4. Heat Exhaustion: This is a precursor to heat stroke. Heat exhaustion can be the body’s response to the excessive loss of water and salt; it could be accompanied by extreme sweating. The condition can be triggered by both physical exertion and limited physical activity. Because heat exhaustion can rapidly progress to heat stroke, an employer should take immediate action. Take the employee to a cool environment; treat the employee with ice packs and cool water/electrolyte drinks; and seek medical attention. If the employee becomes confused or irrational, call 911.
  5. Heat Stroke: Heat stroke is a serious, life-threatening condition that occurs when the core body temperature reaches 104°F—sometimes reaching as high as 106°F within 15 minutes. Common signs and symptoms include loss of consciousness, slurred speech, confusion, seizures and profuse sweating. An employer should administer its emergency action plan for severe workplace injuries, which should include calling 911 immediately for emergency medical care. The employee should be immersed in ice or cold water, applying towels to the head, trunk, extremities and groins. If not treated immediately, a heat stroke victim could experience significant or permanent damage to vital organs such as the heart and kidneys. Death can even occur if treatment is delayed.

While these conditions can affect anyone exposed to extreme heat for a prolonged period, individuals with certain pre-existing medical conditions such as high blood pressure and heart disease can have a lower heat tolerance and be at greater risk.


Heat acclimatization is critical to how an employee’s body reacts to working in extreme heat. Acclimatization occurs after repeated exposure to heat, allowing the body to adapt to functioning in hot environments. Everything from the body’s heart rate and core temperature to the body’s ability to produce sweat and regulate electrolyte loss depends on how well the body acclimates to excessive heat exposure.

For industries like construction, the National Institute for Occupational Safety and Health (NIOSH) recommends that employers take gradual steps to acclimate employees to extreme heat. This is especially critical for new employees, employees returning from a prolonged absence and employees returning from a heat-related illness. This process involves establishing an acclimatization schedule of no more than 20% heat exposure on day one (or the first day back) and an increase of no more than 20% heat exposure each additional day for healthy unacclimatized employees. Various factors can influence an employee’s acclimatization period, such as an individual fitness level, pre-existing medical conditions (e.g., heart disease) and the level of heat stress experienced by an employee returning to work.


Heat-related illness can be preventable if a company is committed to providing the most effective controls. An effective heat-related illness prevention program is incorporated into a broader safety and health program and aligns with the core elements of OSHA’s recommended practices for safety and health programs.

Employees who have not spent time recently in warm or hot environments and/or been physically active will need time to acclimate to the heat. During their first few days in warm or hot environments, it is recommended that construction site employees:

  • Consume adequate fluids (e.g., water, sports drinks)
  • Work shorter shifts
  • Take frequent breaks

Engineering controls such as air conditioning (i.e., with cooled air and increased air flow, leading to increased evaporative cooling) can also make the work environment safer. And to ensure a proper response during a heat-related incident, employees should receive first-aid training and learn how to identify symptoms of a heat-related illness.


Coping with extreme heat is a recurring challenge for construction companies. As different parts of the country continually experience abnormally high temperatures during the peak months of construction work, these businesses must have a response plan in place that incorporates mitigation strategies along with procedures for a rapid response to heat-related emergencies. Having a response plan helps to ensure construction employees are better protected from the dangers and adverse effects of excessive occupational heat exposure.

by Deepa Rajakrishnan
Deepa Rajakrishnan, MD, MBA, is a physician and director of medical operations at Concentra. She oversees more than 30 clinicians to ensure quality care at Concentra medical centers in north Texas. She is board-certified in family medicine and specializes in occupational medicine and urgent care. As a member of Concentra’s Regulatory Testing and Exams Medical Expert Panel, Dr. Rajakrishnan helps ensure accuracy and efficiency of regulated and non-regulated exams across all Concentra medical centers.

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