What is Heat Stress?
Working where it is hot puts stress on your body’s cooling system. When heat is combined with other stresses such as hard physical work, loss of fluids, fatigue or some pre-existing medical conditions, it may lead to heat-related illness, disability and even death. This can happen to anybody – even the young and fit. Heat exposure & stress is prevalent in our industry, because we work outside for long periods in open areas with high exposure to the sun.
How we cope with heat?
Your body is always generating heat and passing it into the environment. The harder your body works, the more heat it has to lose. When the environment is hot and/or humid or has a source of radiant heat (such as a furnace or the sun), your body must work harder to get rid of heat. If the air is moving (for example, by fans) and it is cooler than your body, it is easier for your body to pass heat into the environment.
Workers on medication or with pre-existing medical conditions may be more susceptible to heat stress because some medication and/or medical conditions may impair the body’s response to heat. Such workers should speak to their personal physicians to see if their medication(s) and/or health condition(s) affect their ability to work in hot environments.
Heat-Stress–related disorders
Cause Symptoms Treatment Prevention
Heat rash Hot humid environment; plugged sweat glands. Red bumpy rash with severe itching. Change into dry clothes and avoid hot environments. Rinse skin with cool water. Wash regularly to keep skin clean and dry.
Heat cramps Heavy sweating from strenuous physical activity drains a person’s body of fluid and salt, which cannot be replaced just by drinking water. Heat cramps occur from salt imbalance resulting from failure to replace salt lost from heavy sweating. Painful cramps occur commonly in the most worked muscles (arms, legs or stomach); this can happen suddenly at work or later at home.
Heat cramps are serious because they can be a warning of other more dangerous heat-induced illnesses. Move to a cool area; loosen clothing, gently massage and stretch affected muscles and drink cool salted water (1½ to 2½ mL salt in 1 litre of water) or balanced commercial fluid electrolyte replacement beverage. If the cramps are severe or don’t go away after salt and fluid replacement, seek medical aid. Salt tablets are not recommended. Reduce activity levels and⁄or heat exposure. Drink fluids regularly. Workers should check on each other to help spot the symptoms that often precede heat stroke.
Fainting Fluid loss, inadequate water intake and standing still, resulting in decreased blood flow to brain. Usually occurs in un-acclimatized persons. Sudden fainting after at least two hours of work; cool moist skin; weak pulse. GET MEDICAL ATTENTION. Assess need for cardiopulmonary resuscitation (CPR). Move to a cool area; loosen clothing; have the person lie down; and if the person is conscious, offer sips of cool water. Fainting may also be due to other illnesses. Reduce activity levels and⁄or heat exposure. Drink fluids regularly. Move around and avoid standing in one place for too long. Workers should check on each other to help spot the symptoms that often precede heat stroke.
Heat exhaustion Fluid loss and inadequate salt and water intake causes a person’s body’s cooling system to start to break down. Heavy sweating; cool moist skin; body temperature over 38°C; weak pulse; normal or low blood pressure; person is tired and weak, and has nausea and vomiting; is very thirsty; or is panting or breathing rapidly; vision may be blurred. GET MEDICAL ATTENTION. This condition can lead to heat stroke, which can cause death quickly. Move the person to a cool shaded area; loosen or remove excess clothing; provide cool water to drink; fan and spray with cool water. Do not leave affected person alone. Reduce activity levels and⁄or heat exposure. Drink fluids regularly. Workers should check on each other to help spot the symptoms that often precede heat stroke.
Heat stroke If a person’s body has used up all its water and salt reserves, it will stop sweating. This can cause body temperature to rise. Heat stroke may develop suddenly or may follow from heat exhaustion. High body temperature (over 41°C) and any one of the following: the person is weak, confused, upset or acting strangely; has hot, dry, red skin; a fast pulse; headache or dizziness. In later stages, a person may pass out and have convulsions. CALL AMBULANCE. This condition can kill a person quickly. Remove excess clothing; fan and spray the person with cool water; offer sips of cool water if the person is conscious. Reduce activity levels and/or heat exposure. Drink fluids regularly. Workers should check on each other to help spot the symptoms that often precede heat stroke.
Controlling Heat Stress
Acclimatization
The longer you work in a hot environment, the better your body acclimatizes to the heat. If you are ill or away from work for a week or so you can lose your acclimatization. Be aware that it may take you a little while to become acclimatized again, and take the necessary steps to protect yourself. If you have health problems or are not in good physical condition, you may need longer periods of acclimatization.
When there is a potential for exposure to heat stress, control measures must be taken to prevent heat exposure in the workplace. These include engineering controls, administrative controls and protective clothing. Selection of appropriate workplace controls will vary, depending on the type of workplace and other factors. Some measures may include:
Engineering controls
• Reduce physical demands of work task through mechanical assistance
• Reduce the temperature and humidity of your rest area (doghouse) through air conditioning
• Provide cool, shaded work areas
• Increase air movement if temperature is below 35°C (e.g. use fans).
Administrative controls
• Assess the demands of all jobs and have monitoring and control strategies in place for hot days
• Increase the frequency and length of rest breaks on hotter days
• Provide cool drinking water and drink a cup about every 20 minutes, or more frequently, to stay hydrated
• Train staff to recognize the signs and symptoms of heat stress and start a buddy system since people are not likely to notice their own symptoms
• Investigate any heat–related incidents
• Trained First Aiders are available and an emergency response plan should be in place, for hot days, in the event of a heat related illness.
Protective clothing
• Light summer FR coveralls should be worn to allow free air movement and sweat evaporation
If you have ever had a heat stress related ailment, you’ll know that it was not enjoyable and you do not want to go through the experience again. Take all the precautions possible and ensure if you feel the symptoms of heat stress that you tell your supervisor, take a break, and take in ample amounts of fluid!