Chapter 6 - Water

Learning Outcomes

After reading through this chapter, you should be able to:

  • Explain why being hydrated is important for alertness.
  • Name factors that contribute to dehydration.
  • Determine whether you are drinking enough water daily to stay hydrated.

Can hydration affect alertness?

As mentioned earlier in this workbook, it is not just sleep that affects your alertness. Examples have been provided related to digestion and food. Similarly, hydration has an affect on your ability to feel alert and be safe.

When your body is low on water, it tries to conserve what you have left. It does this by reducing your activity and making you relax and slow down. When you are relaxed, you have a higher chance of falling asleep. Being dehydrated can also make you feel lightheaded and cause headaches.

Most people do not drink enough water to be fully hydrated. In extreme cases, this can result in medical problems, including kidney problems. In most cases, however, the effects of dehydration are short term and are easily solved by drinking more water.

Contributors to dehydration

The recommended daily intake of water is two litres or eight glasses. Drinking less than this contributes to dehydration. There are other factors that can cause dehydration, even if your daily intake of water is adequate. Some of these factors include:

  • Performing physically demanding tasks
  • Drinking a lot of caffeinated drinks. Caffeine is a diuretic, a substance that actively flushes water from your body
  • Working in hot environments
  • Drinking alcohol, which is also a diuretic
  • Drinking soft drinks, which may not provide the same degree of hydration as plain water
  • Eating foods that are high in salt, which require additional water to be processed through the body

Another problem can be the availability of water in the workplace. For example, many employees who drive vehicles for a living do not have access to water unless they bring it with them.

To be as alert and awake as possible, you need to be aware of your water intake. For some people, this may mean doubling their fluid intake or more. Surprisingly, many people find that when they drink more water they feel more alert but don’t go to the toilet any more often – their urine output is simply higher each time.


What sort of fluids do you drink at work?


Approximately how much water do you drink at work?


Based on what you have just read, do you think you need to make any changes in your drinking habits? Provide details.


Case study

Man with a drinkTerry is a 52-year-old pilot who has been flying for 24 years. He flies 100 to 110 hours per month at all hours of the day.

A while ago, Terry’s friend suggested that drinking water might help him feel more alert while flying. She also recommended that he think more about when he drinks coffee and alcohol.

Now Terry only drinks coffee when he is really tired. This way he reduces his dehydration from caffeine but still gets its stimulating benefits. Terry also drinks more water now but doesn’t need to go to the toilet any more frequently. Although he was initially sceptical, these new strategies have helped Terry feel more alert.


checkmark Knowledge Check

  • Why might Terry have to go to the toilet more frequently when he drinks caffeinated drinks?
  • What effects do alcohol and caffeine have on water in the body?
  • How does water affect alertness?
  • On average, what is the minimum amount of water you should drink every day?
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