Although heat stress can happen any time of the year, most cases occur in the warmer weather months. A smartphone app developed by OSHA and NIOSH allows workers to calculate the heat index for their worksite, and, based on the heat index, displays a risk level to outdoor workers. Then, with a simple "click," you can get reminders about the protective measures that should be taken at that risk level to protect workers from heat-related illness-reminders about drinking enough fluids, scheduling rest breaks, planning for and knowing what to do in an emergency, adjusting work operations, gradually building up the workload for new workers, training on heat illness signs and symptoms, and monitoring each other for signs and symptoms of heat-related illness.

https://www.osha.gov/heat/heat-app

Working in full sunlight can increase heat index values by 15 degrees Fahrenheit. Keep this in mind and plan additional precautions for working in these conditions.

According to OSHA, every year thousands become sick from heat stress and some of those cases are fatal. In 50% to 70% of the outdoor heat illnesses occur in the first few days of working in warm or hot environments because the body needs to build a tolerance to the heat gradually over time. The process of building tolerance is called heat acclimatization. Lack of acclimatization represents a major risk factor for death due to heat stress. Workers also at risk of heat stress include those who are 65 years of age or older, or are overweight, have heart disease or high blood pressure, or take medications that may be affected by extreme heat.

Heat stroke is the most serious heat-related illness. It occurs when the body becomes unable to control its temperature: the body’s temperature rises rapidly, the sweating mechanism fails, and the body is unable to cool down. When heat stroke occurs, the body temperature can rise to 106°F or higher within 10 to 15 minutes. Heat stroke can cause death or permanent disability if emergency treatment is not given.

Heat exhaustion is the body’s response to an excessive loss of the water and salt, usually through excessive sweating. Workers most prone to heat exhaustion are those that are elderly, have high blood pressure, and those working in a hot environment.

Rhabdomyolysis is a medical condition associated with heat stress and prolonged physical exertion, resulting in the rapid breakdown, rupture and death of muscle. When muscle tissue dies, electrolytes and large proteins are released into the bloodstream that can cause irregular heart rhythms and seizures, and damage the kidneys. The symptoms of rhabdomyolysis include muscle pain or cramps and tea-colored urine.

Heat syncope is a fainting episode or dizziness that usually occurs with prolonged standing or sudden rising from a sitting or lying position. Factors that may contribute to heat syncope include dehydration and lack of acclimatization.

Heat cramps usually affect workers who sweat a lot during strenuous activity. This sweating depletes the body’s salt and moisture levels. Low salt levels in muscles causes painful cramps. Heat cramps may also be a symptom of heat exhaustion.

Certain medications are known to decrease the sweat rate of the body. Heat-interacting medications include antidepressants, antihistamines and diuretics. Talk to your doctor or pharmacist and ask if any of your medications fall into these groups.

Keep in mind that the hypothalamus regulates the body temperature by telling our body when and how much to sweat. Make sure that you have enough available liquid and electrolytes in your body so that you can sweat enough to cool down!

• Acclimating to Heat or Cold
• Heat Stress
• First Aid for Heat Illnesses