Working in Hot or Cold Places



Working in really cold or really hot spaces can lead to thermal stress.  A thermal stress evaluation can be requested by contacting Environment, Health, and Safety at (617) 452-3477 or 
Thermal comfort depends on temperature but can be affected by humidity, air movement, rate of activity, clothing, individual acclimatization, and individual preference.


Heat stress

Exposure to heat can cause illness and even death. The most serious heat illness is heat stroke.


Heat Stress Symptoms

  • Headache and/or dizziness
  • Irritability and/or confusion
  • Weakness and/or wet skin
  • Thirst, nausea, or vomiting
  • Loss of consciousness can occur

Heat Stress Prevention

  • Learn about heat stress before taking on work in hot environments (locally or out in the field)
  • Provide lots of cool water (at least 0.5 L) to workers and team members
  • Drink often approximately every 15 minutes
  • Allow more frequent breaks and gradually increase workloads 
  • Routinely check on colleagues workers and use a buddy system
  • Wear lightweight, light colored, loose fitting clothes.
  • Avoid beverages containing alcohol or caffeine

Cold stress

Hypothermia occurs when body heat is lost faster than it can be replaced. Hypothermia can occur at cool temperatures above 40°F or 4°C, if a person becomes chilled from rain, sweat, or submersion in cold water.


Cold Stress Symptoms

  • Shivering and stomping feet in order to generate heat
  • Loss of coordination and fumbling with items in the hand
  • Confusion or disorientation
  • Inability walk or stand, pupils become dilated, pulse and breathing become slowed
  • Loss of consciousness can occur

Cold Stress Prevention

  • Learn about cold stress before taking on work in cold environments (locally or out in the field)
  • It is easy to become dehydrated in cold weather, so ensure there are plenty of warm sweetened liquids available
  • Dressing properly is extremely important to preventing cold stress. Wool, silk, or a synthetic may offer better insulation even when wet.
    • Wear at least three layers of loose fitting clothing (layering provides better insulation)
    • Wear a hat it reduces the amount of body heat that escapes from your head
    • Use insulated gloves to protect the hands (water resistant if necessary)
    • Wear insulated and waterproof boots (or other footwear)
  • Radiant heaters may be used to warm workers, or shield work areas from drafts and  wind to reduce wind chill
  • Routinely check on colleagues workers use a buddy system
  • Avoid beverages containing alcohol

If you are concerned, please contact EHS at (617) 452-3477 or