Working in extreme heat poses significant health risks. Extreme heat refers to prolonged periods of high temperatures, typically above 95°F (35°C), often coupled with high humidity. The heat index, which combines air temperature and relative humidity, is a crucial measurement as it represents how the heat feels to the human body. A heat index of 104°F (40°C) or higher is considered dangerous.
Effects of extreme heat
When exposed to extreme heat, the body strives to maintain a stable internal temperature through various mechanisms:
Sweating is the primary way the body cools itself because as sweat evaporates from the skin, it takes heat away
Blood vessels near the skin's surface dilate, increasing blood flow to the skin to release heat
The heart works harder to pump blood to the skin for heat dissipation, creating an elevated heart rate
However, prolonged exposure to extreme heat can overwhelm these cooling mechanisms, leading to several heat-related illnesses:
Heat cramps. Painful muscle spasms caused by the loss of electrolytes through sweating. Symptoms include muscle pain or spasms, usually in the legs or abdomen.
Heat exhaustion. A more severe condition marked by heavy sweating, weakness, dizziness, nausea or vomiting, tiredness and fainting. It occurs when the body loses too much water and salt.
Heat stroke. The most severe heat-related illness, where the body's temperature regulation fails. Symptoms include high body temperature above 104°F (40°C), hot and dry skin, confusion, slurred speech, seizures and unconsciousness. Heat stroke is a medical emergency and can be fatal if not treated promptly.
Keeping cool
When working in extreme heat, implementing effective cooling strategies is essential. Here are some steps to take:
Drink plenty of fluids, preferably water or sports drinks that replace electrolytes. Avoid caffeine and alcohol, as they can dehydrate you.
Wear lightweight, loose-fitting, and light-colored clothing to reflect heat. A wide-brimmed hat can provide additional protection from the sun.
Take frequent breaks in shaded or air-conditioned areas to cool down.
If possible, schedule heavy labor during the cooler parts of the day, such as early morning or late afternoon.
Use fans, cooling towels or portable air conditioners to help regulate body temperature.
Gradually increase the duration of heat exposure over several days to allow your body to adapt.
Sources: The National Institute for Occupational Safety and Health, U.S. Department of Labor, Occupational Safety and Health Administration
