Extreme Temperatures


Extreme temperatures can cause various problems for workers. Hot temperatures can lead to dehydration and muscle fatigue, especially in conjunction with high humidity. Cold temperatures make the muscles less flexible, resulting in muscle strain and pulls. Problems may include: trouble breathing, fatigue, reduced dexterity, sensory sensitivity, and reduced grip strength.

Hot or cold work environments can be encountered in areas beside the outdoors. Any location that is outside of the typical comfort zone of 55 to 85 degrees F is cause for consideration. Temperature should “fit” the worker much like a chair or tool.

Hot Environment

When a worker is subjected to a high heat environment, the internal body temperature rises resulting in the bodies attempt to regulate its temperature through increased blood circulation and increased perspiration. Relatively less blood goes to the active muscles, brain, and other internal organs; strength is reduced, and fatigue occurs sooner. If the body is prevented from cooling down, the body will continue to try to cool down and expend more energy, increasing fatigue. Heat stroke and heat exhaustion are the most serious health issues caused by working in hot environments. HEAT STROKE can be fatal and victims usually don’t recognize the symptoms. While the symptoms vary from person to person, they include dry, hot skin (due to a failure to sweat), an elevated body temperature, and ultimately a partial or complete loss of consciousness. HEAT EXHAUSTION is caused by a loss of body fluid through excessive sweating. Symptoms include heavy sweating, weakness, dizziness, intense thirst, nausea, headache, vomiting, diarrhea, muscles cramps and possibly palpitations.

The best solution to working in a hot environment is to reduce the temperature or remove the worker. This should be attempted first by increasing ventilation and/or cooling or providing heat shields as appropriate. This is not always practical and other solutions may have to be employed to mitigate the impact of the heat to the individual. Alternating work or implementing a work-rest schedule may provide relief. Additionally, workers should:
  • Drink fluids, preferably water, throughout the day to replace lost water,
  • Limit caffeine intake,
  • Protect yourself when working outdoors by covering up as much as possible,
  • Wear light weight, breathable fabrics,
  • When working outdoors, perform strenuous work during the coolest times of the day, reserving lighter tasks for the high heat periods.
  • Take rest periods to allow the body time to cool off,
  • Know the signs of heat stress and heat exhaustion.

Cold Environment

Low temperatures reduce sensory feedback, dexterity, blood flow, muscle strength, and balance. This can impact performance of complex mental and physical tasks and may even lead to potentially lethal side effects. A cold environment takes away body heat which can result in a lowering of the inner body temperature to dangerously low levels. HYPOTHERMIA is a common cold injury associated with low body heat. This occurs when the body loses energy faster then it is produced, dropping the body temperature. Warning signs are numbness, stiffness, drowsiness, and poor coordination. FROSTBITE is another common cold injury. The nose, ears, cheeks, fingers, and toes are the most often affected. The low temperature constricts blood vessels, which impair blood flow and may cause permanent tissue damage. If damage is only to the skin and underlying tissue, complete recovery may be expected. However, if blood vessels are affected, the damage may be permanent and could result in amputation of the affected part.

To cope with working in a cold environment you should stay active, dress warmly, and follow the basic safety rules. Working in a cold environment increases the risk of back injuries and other musculoskeletal injuries. Perform “warm up” stretching exercises before doing heavy work or handling heavy equipment and material. Important points to remember are:
  • Dress in multiple layers of loose, dry, protective clothing,
  • Ensure that your hands, feet, face, head, and eyes are covered,
  • Avoid getting wet,
  • Keep moving,
  • Take regular breaks in a warm location.