Working in heat and cold

Trades work happens outside in every season. Both heat and cold can make you seriously ill.

Heat

• Heat cramps: sharp muscle pains caused by a salt imbalance from heavy sweating.
• Heat exhaustion: caused by losing water and salt through heavy sweating. Signs include heavy sweating, weakness, dizziness, intense thirst, nausea and headache. First aid: get medical aid and stay with the person until help arrives; move them to a cooler, shaded spot; remove as much clothing as possible; apply cool, wet cloths or ice to the head, face or neck, or spray with cool water; and encourage them to drink water, clear juice or a sports drink.
• Heat stroke: the most serious heat illness and a medical emergency. Signs include a high body temperature (often over 40°C) and partial or complete loss of consciousness. Call 911 immediately, stay with the person, move them somewhere cooler and shaded, and cool them with water and cold, wet cloths. Don't force them to drink. Delayed treatment may result in death.

Watch out for these signs in yourself and your co-workers.

Cold

• Frostnip is the mildest freezing injury: the top layers of skin freeze. Toes, fingers, ears and nose are most at risk. First aid is gentle rewarming, such as holding the area against warm, unaffected skin. Never rub it, and don't use very hot objects like hot water bottles.
• Frostbite is more serious. Never ignore numbness. Don't rub the area and don't try to rewarm it on site; keep it from getting colder and get medical attention.
• Hypothermia: the most severe cold injury, caused by losing so much body heat that your core temperature drops. It can be fatal. Shivering is an early sign; muscle weakness and drowsiness follow, and shivering may stop as it gets worse. Get medical help and move the person somewhere warm.

Your body loses heat faster when you're wet. Keep dry where you can.

Some provinces and territories have specific heat or cold rules. Check with your regulator and follow your employer's plan.