No sooner does summer arrive then weather stations are issuing heat advisories. For some workers, the heat is a serious occupational hazard.
The human body is usually good at maintaining its ideal temperature of 37 C. At any time of year and in various circumstances, the body produces its own heat and prevents overheating by sweating. In extreme temperatures however, when the air is as hot or hotter than the body, the body’s cooling mechanisms can’t keep up. When the body can no longer cool itself properly, a number of heat-related health problems may occur.
Heat stroke and heat exhaustion are the most serious health illnesses caused by hot environments, and pose a real danger to people who work outside in the summer. In outdoor occupations such as construction, road repair, open-pit mining and agriculture, summer sunshine is the main source of heat. In laundries, restaurant kitchens and canneries, high humidity adds to the heat burden. In all instances, the cause of heat stress is a working environment which can potentially overwhelm the body's ability to deal with heat.
Without immediate medical attention, heat stroke can be fatal. In previous years, people have died of heat stroke at work in occupations ranging from agriculture workers to football players. Heat exhaustion, fainting, heat cramps and heat rashes are other less harmful, heat-related health risks that can cause temporary illness.
Know the warning signs
?Heat stroke victims usually don't recognize their own symptoms. Their survival therefore depends on their co-workers' abilities to detect symptoms and seek first aid and medical help immediately. While the symptoms vary from person to person, they include dry, hot skin (due to failure to sweat) or profuse sweating, a very high body temperature (often exceeding 41 C), hallucinations, confusion, seizures and complete or partial loss of consciousness.
Signs of heat exhaustion include heavy sweating, weakness, dizziness, thirst, nausea, headache, vomiting, diarrhea, muscle cramps, and elevated body temperature. Heat exhaustion can quickly progress to heat stroke.
[strong]How to prevent health problems from overheating
• Avoid sun exposure: Move some tasks indoors or into the shade. When that's not possible, erect a temporary shelter. Take frequent breaks in a cool or well-ventilated area to get out of the sun and heat. Schedule hot jobs for the cooler part of the day (early morning, late afternoon or night shift).
• Don't be afraid to sweat: Sweating is the body's most effective cooling mechanism. The cooling occurs as sweat evaporates. In some cases a fan can be used to move cool air into a room and help keep body temperatures down.
• Become acclimatized: Don't take on strenuous activities too soon if you're not accustomed to the heat. It can take seven to 14 days for the body to fully adapt (or acclimatize) to a hot environment. Ease into your tasks gradually, taking frequent breaks from the heat as needed. It is advisable to assign about half of the normal workload to new employees or those back from vacations or illnesses on the first day of work and gradually increase day by day.
• Stay hydrated: Drink plenty of cool water (on average one litre every hour) in hot weather conditions. Drink every 15 to 20 minutes whether you feel thirsty or not to replace the fluid loss. Avoid consuming caffeine and alcohol, which can dehydrate you.
• Wear appropriate clothing: For protection from the sun and heat when working outside, cover up as much as possible with loose-fitting clothes made of a light fabric that breathes. When you work in the sun without a shirt or hat, the sun dries your sweat too quickly and prevents it from cooling the body.
• Watch for signs: Learn to recognize the signs of heat-related illnesses, and how to respond to them.
• Have an emergency action plan: An emergency plan should include procedures for providing affected workers with first aid and medical care. Workplaces where heat stress can occur should monitor conditions and ensure that workers get specified rest periods dependent on the measured heat levels. The Threshold Limit Values for Heat Stress and Strain, produced by the American Conference of Governmental Industrial Hygienists (ACGIH) offers guidelines to determine when the weather should have no effect on outdoor workers, when caution should be exercised and when work should be discontinued.
The Canadian Centre for Occupational Health and Safety (CCOHS) is Canada's national resource for the advancement of workplace health and safety. CCOHS promotes the total well being — physical, psychosocial and mental health — of working Canadians by providing information, training, education and management systems and solutions that support health and safety programs and the prevention of injury and illness. Visit www.ccohs.ca for more information.