Hesperian Health Guides

Dangers from heat

When you get very hot, your body sweats to cool off. And when you sweat, your body loses liquid. To stay healthy, you need to drink enough water to replace the liquid you lose as you sweat. If you do not drink enough water or if you do not get regular breaks from the heat, you can get sick very quickly.

The first signs of too much heat are heavy sweating and a quicker heartbeat. If you begin to have a headache, feel weak or tired, have painful muscle cramps, or feel dizzy, confused, or nauseous, you are in danger of heat illness. As soon as you feel these warning signs, you need to begin cooling off or you could collapse.

a woman speaking
If it is very humid inside the factory you might not notice you are sweating or how hot your body is getting.

If you keep working past these signs, you might suffer heatstroke. One sign of heatstroke is that you no longer sweat even if you are very hot. Heatstroke happens because your body gets too hot and it overheats your brain. It can cause permanent damage to the brain and other organs, and can kill you.

Other health problems caused by too much heat include:

  • skin rashes, boils, or infected hairs
  • heart problems
  • vaginal infections, especially in women who sit most of the time, and whose clothing stays damp with sweat
  • pregnancy complications and miscarriage
  • fewer sperm in men, making it difficult to conceive a child

Too much heat is especially dangerous for people with heart problems, high blood pressure, diabetes, and for people taking certain tranquilizers or medicine for nausea.

When people start a new job in a hot factory, it affects them more. Watch co-workers for signs of too much heat, especially in the first few weeks.

Stand together, fan together
a woman fanning herself.

I work in a shoe factory in Reynosa, Mexico. After work, I meet with a group of women to talk about problems at work. When the air conditioning in the factory broke a few months ago, the manager said fixing it was too expensive. We started to talk about how sick we felt working in the heat. The manager did not listen to us when we asked him to fix the air conditioner, so our group decided to find another way to convince him. One morning we walked into the factory, but we did not start working. We sat down and started fanning ourselves. Other workers saw what we were doing and joined us. Soon all the workers in the factory had stopped working and started fanning. By the end of the day, the manager had fixed the air conditioning!

Cool the air inside the factory

The best way to protect workers from too much heat is to keep the air inside the factory cool and give workers time to rest, to cool off, and to drink enough safe, clean water. (For information about ventilation, see Chapter 17.)

Rest and drink water

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  • Drink cool water whenever you feel thirsty. It is better to drink a little bit of water several times a day than drink a lot at one time. Do not drink coffee or cola because they will dehydrate you. Policies that let workers take enough bathroom breaks help them stay hydrated and healthy.
  • Take rest breaks. If your job makes you very hot, you should rest in a cool area for 5 minutes to recover. Take as many cooling breaks as you need.
  • Wear loose-fitting, lightweight clothes that let air through to your skin to help dry your sweat and cool your body. Loose underclothes made of cotton, instead of nylon, can also help prevent skin rashes and infections.
  • Limit time working in very hot areas by rotating jobs, so that nobody works in high heat all day or every day.
First aid for heat illness

Pay attention to people who act confused or delusional when working in a hot environment. The person is probably suffering from heat illness, though these are also signs of chemical exposure. Take action immediately. Do not wait until a person faints to give first aid.

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  1. Have the person lie down in a cool place.
  2. Raise his feet and rub his legs.
  3. Give him cool water to drink. You can give juice or other drinks if that is all you have, but do not give coffee or cola.
  4. Place cold cloths on his face and neck.
  5. If the person faints, get medical help right away.

Muscle cramps caused by heat

When you sweat too much and do not drink enough to replace it, your muscles will cramp. Drink fluids regularly during the day to prevent muscle cramps.

If you have a cramp in your legs, arms, or belly:

  1. Every hour until the cramps are gone, slowly drink 1 liter of cool water or rehydration drink, juice, or any drink except for coffee or cola.
  2. Sit or lie down in a cool place.
  3. Gently massage the painful areas.

To make rehydration drink:

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  1. Pour 1 liter of clean water in a container.
  2. Add ½ teaspoon of salt.
  3. Add 8 flat teaspoons of sugar and mix well.

Give as much as the person will take. For more on rehydration drink, see Where There is No Doctor.
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This page was updated:28 Feb 2021