Hazardous conditions when working in summer’s heat and humidity can range from the dangers of safety glasses fogging up leading to an obstructed view, to the more serious heat-related illnesses, which can be potentially fatal. Understanding how to prevent heat-related illnesses can take much if not all the risk out of working outside during the summer months. When a heat-related illness happens, it is critical to know to recognize the symptoms quickly and administer treatment.
This hazard can be mitigated by using the hierarchy of controls. Implement engineering controls provided by the shade and air conditioning of vehicles, or even offices for breaks and make sure that every employee has access to hydration sources. Administratively, we educate on risk factors and early heat-related Illness warning signs, promote proper hydration, monitor the weather forecasts and adjust schedules or jobs accordingly, promote taking breaks in shaded areas and using the buddy system. PPE controls include wide-brimmed hats, sunglasses, sunscreen and lightweight, light-colored, fast-drying clothing to promote sweat evaporation.
Physiology
Heat-related illnesses develop when the body’s two cooling mechanisms of sweating and blood vessel dilation aren’t able to rid the body of heat. Sweat evaporating from skin cools the body but can result in significant dehydration. When the relative humidity is high, sweat doesn’t evaporate quickly. Blood brought close to the skin surface releases heat. If the air temperature exceeds body temperature, the body cannot easily cool itself. Both conditions can lead to cardiovascular strain.
Hyperthermia is when the core body temperature of an individual is higher than 99°F. Heat stroke is potentially fatal without treatment as core temperatures can soar to >113°F!
Thirst is typically a sign you are already dehydrated. Drinking large quantities of water causes us to sweat and urinate more leading to significant loss of electrolytes, including sodium and calcium, which are key in thermoregulation. Working in hot conditions requires a balanced fluid-replacement strategy to prevent symptoms including headache, weakness, nausea and cramps, which may become a potentially life-threatening illness known as hyponatremia.
While working in the heat, employees should drink 8 ounces of water and other fluids every 15 to 20 minutes. During strenuous, prolonged work over two hours in hot conditions, 1/3 to 1/2 of fluid intake should be in sports drinks to replace the electrolytes lost from sweating. These electrolytes will also help reduce fluids lost when urinating. Alcohol and caffeine have diuretic properties that may cause dehydration or lead to a delay in rehydrating and should be avoided.
Heat Cramp: Sweating profusely during strenuous activity depletes the body’s salt and moisture. The loss of electrolytes causes lower salt levels in muscles which leads to cramping – usually in the abdomen, arms, legs.
First Aid:
- Rest briefly
- Cool down
- Stretch
- Replenish electrolytes with sports drinks
- If needed, delay strenuous activities for several hours after heat cramps subside
Heat Exhaustion: 100.4°F –103.1°F
This illness is often considered a leading indicator of the more serious heat stroke if not addressed quickly. It is the body’s response to an excessive loss of the water and salt contained in sweat and results in reduced performance of one or more organ systems. This illness may take several days of exposure to high temperatures and inadequate or unbalanced replacement of fluids to develop depending on the individual. Symptoms: Headache, dizziness, or fainting, weakness and wet skin, irritability or confusion, thirst, nausea, or vomiting.
First Aid:
- Move the person out of the heat and into shade or air conditioning.
- Lay the person down and slightly elevate the legs and feet.
- Remove tight or heavy clothing.
- Have the person drink cool water or other nonalcoholic, caffeine-free fluid.
- Cool the person by spraying or sponging with cool water and fanning.
- Monitor the person carefully, contact a physician if symptoms do not improve within one hour and call 911 immediately if the person's condition deteriorates.
Heat Stroke: >103.1°F extremely serious above >104.9°F
Strenuous activity in excessive heat can lead to a rapid rise in core body temperature. When combined with the failure of the body’s temperature-regulating mechanism (sweating), the body cannot cool down resulting in damage to the central nervous system, which can then cascade to affect other vital organs. Heatstroke can be permanently disabling or fatal if emergency treatment is not provided.
Symptoms: Sudden and sustained loss of consciousness, seizures, may stop sweating and have hot, flushed, or dry skin. Often these symptoms are preceded by vision loss, rapid pulse and breathing, vertigo, nausea, headache, cerebral dysfunction, or other bizarre behavior such as agitation or confusion.
First Aid:
CALL 911.
- Move the person out of the heat, into shade or air conditioning.
- Remove excess clothing.
- Cool by whatever means available, including:
- Place in a tub of cool water or a cool shower.
- Spray with a garden hose.
- Sponge with cool water.
- Fan while misting with cool water.
- Place ice packs or cool wet towels on the neck, armpits and groin.
- Cover with cool damp sheets.
