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Health & Safety: avoid dehydration

Stay hydrated working in heat

June 5, 2018  By By the CCOHS

It’s humid and the temperatures are soaring. You’ve been working hard for hours. You feel dizzy, have a pounding headache, and your intense thirst suddenly reminds you that it’s been hours since you’ve paused to drink something. You may be dehydrated, and that can cause severe health problems if left unchecked.

About 60 per cent of your body is made up of water. Water is essential to human life. You need it to keep your body functioning properly and to regulate your body temperature. It flushes out wastes and toxins, helps digestion, lubricates the joints and eyes, and keeps skin healthy. You can’t live without it.

How you can become dehydrated
When you don’t drink enough fluids to replace the water that you lose through sweating and everyday activity, you can become dehydrated. When the normal water content of your body is reduced, it upsets your body’s balance of minerals (salts and sugar), which affects the way that it functions. Just a small drop in body fluids will cause a loss of energy in the average person and a 15 per cent drop in body fluids can cause death.

There are several factors that can contribute to dehydration: environment, amount of physical activity, illnesses or health conditions, and diet.


Working outside in sun, heat, and humidity can cause you to sweat and lose fluids rapidly. Heated indoor air also can also cause loss of fluids. Being in high altitudes, greater than 2,500 metres (8,200 feet), may increase the amount you urinate and quicken your breathing, in turn, using up more of your body fluids.

If you do strenuous work or intense exercise that causes you to sweat, you are at increased risk for dehydration.


You can also become dehydrated as a result of an illness or a health condition. Fever, vomiting, or diarrhea can cause your body to lose additional fluids, as would a condition such as diabetes that causes frequent urination.

Drinking too much alcohol can dehydrate you. As well, drinking sugary soda and coffee or tea to satisfy your thirst yourself can actually dehydrate you even more. These drinks usually have caffeine that can cause you to urinate more. Also, drinking anything loaded with sugar makes your body work harder to process it, causing further dehydration.

Signs of dehydration
Dehydration can be described as mild, moderate or severe. Watch for the following signs.

Mild to moderate

  • excessive thirst
  • dizziness or light-headedness
  • headache
  • fatigue or drowsiness
  • dry mouth, lips and eyes
  • dark yellow urine
  • urinating only small amounts, infrequently (less than three or four times a day)

Moderate dehydration causes you to lose strength and stamina, and is the main cause of heat exhaustion. You should be able to reverse this level of dehydration yourself by drinking more fluids.

If dehydration is ongoing, it can affect your kidney function and cause kidney stones, liver, joint and muscle damage, cholesterol problems, and constipation.

Untreated mild or moderate dehydration can lead to severe dehydration, which is a medical emergency that requires immediate medical attention. Watch for the following symptoms:

  • dry, wrinkled skin that falls slowly into position when pinched up
  • unable to urinate or not urinating for eight hours
  • feeling drowsy, disorientated, and irritated
  • sunken eyes
  • weak pulse
  • rapid heartbeat
  • cool hands and feet
  • seizures
  • blood in your feces or vomit

Mental performance and concentration begin to decrease as you become increasingly dehydrated, affecting the safety of yourself and those around you.

What employers can do to help prevent dehydration
Employers have a duty to provide and maintain a safe working environment. Employers can:

  • Educate employees on the causes and to recognize the symptoms of dehydration, and instruct them on how to protect themselves.
  • Continuously reinforce the messages with ongoing training and visual reminders (posters, for example) to encourage employees to hydrate themselves, and watch for signs of dehydration in themselves and others.
  • Make sure there is a buddy system in place so workers can monitor one another for signs of dehydration. People are generally unable to notice their own heat stress related symptoms.
  • Make drinking water readily accessible and encourage your employees to drink often, even if they do not feel thirsty.
  • Where possible, plan the work so that more strenuous work is done during cooler periods.
  • Provide shade or shelters as relief from heat and rest areas for outdoor workers.
  • Have an emergency plan in place that includes procedures for providing affected workers with first aid and medical care. This plan is a necessity, especially in extreme environments.

What employees can do to prevent dehydration
The recommended daily intake of fluids can vary depending on the individual and on factors such as age, climate, and physical activity.

  • Drink plenty of water to replace the fluids you are losing, at least a cup every 15 or 20 minutes. For most people water is the most efficient fluid for re-hydration. Sports drinks, electrolyte drinks or juice designed to replace body fluids and electrolytes may be taken diluted to half strength with water is an option when used in moderation. For most people, these drinks add unnecessary sugar or salt to your diet.
  • Fluid intake should equal fluid loss. On average, about one litre of water each hour may be required to replace the fluid loss.
  • Avoid caffeine and sugary drinks, and NEVER consume alcohol to hydrate.
  • Monitor your urine colour. It should be clear to light yellow. If it is darker or concentrated, you may be dehydrated, and you must drink more fluids.

If you or a co-worker show signs or symptoms of dehydration, call for medical help immediately. Severe dehydration can lead to complications and even death.

The Canadian Centre for Occupational Health and Safety (CCOHS) promotes the total well being of workers in Canada by providing information, training, education,  systems and solutions that support health and safety programs and injury and illness prevention. www.ccohs.ca

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