Mr and Mrs Nutritionist

Why Should You Stay Hydrated?

Water is vital for life, it is needed for crops, animals and humans. It is the reason why NASA is trying so hard to find evidence of water on Mars because no water = no life. But not all water is safe to drink. Much of the water on Earth is seawater which contains too much salt, while other water sources may be filled with contaminates such as what is currently occurring in Flint, Michigan with rust particles. Nevertheless water is a daily requirement. When dehydration occurs a persons physical and mental ability to perform is hindered. Water seems so basic and unimportant, here we explain the importance on ‘why you should stay hydrated’.

Water Transport

The most common way water is transferred around the body is through osmosis (concentration variation). For instance water will automatically travel where there is less of it until there is equal amounts on either side (left picture). This balance can be altered with the use of salts (sodium). Sodium can control water (to a certain degree). As shown below sodium can “drag” water from the left side of the tube to the right, where sodium concentration is highest, increasing the volume like so (as shown below in the right picture). Screen Shot 2016-03-21 at 17.10.31

Sodium and water within the blood will pass through the kidneys, and the kidneys will remove the sodium and the water. As the sodium content in the kidney is higher than the outside the water will stay in the kidney. From the kidney it will pass into the bladder and then will be excreted as urine. This mechanism is why you will get thirsty when consuming salty snacks. The body can reabsorb water from the kidneys but only if the sodium content is below a certain threshold.

A similar mechanism occurs with people who suffer from uncontrolled diabetes, except instead of there being too much salt there is too much sugar.

The Water Balance

Water you ingest should be equal to water you excrete, simple right? Unfortunately, it is not as black and white as this. We can get water into the body in various ways such as food, drink or in desperate times through an IV. For healthy individuals 80% of a daily persons water is through drinking, and the remaining 20% is through food.

So in total how much water should you consume? The Institute of Medicine have set out some recommendations;

  • Men: 124 fluid ounces or approximately 1 gallon (3.7 liters).
  • Women: 91 fluid ounces or approximately 2/3 of a gallon  (2.7 liters)

Remember these recommendations include the 20% from your food intake.

However, you should increase your intake if you partake in physical exercise, live in a hot and humid climate or have an increased sweat production due to infection, sickness or suffering from a medical condition in which you are advised to drink more.

Water can exit the body in numerous ways. Urine, feces and sweat are the primary exits for water. However during times of sickness excess water can leave via diarrhea, vomit and excess sweating during fever, which is why it is vital to have a lot of fluids when you are not feeling well.


Why should you stay hydrated

This is a urine colour chart. The colour of your pee determines how hydrated you actually are. Where is yours?

When water levels are too low in the body, the body redirects water to where it needs to be. You may have noticed that your urine may turn a different color depending on if you have or haven’t drunk enough over the course of the day. Themore yellow the urine is, the more dehydrated you are. This is because the kidneys are highly efficient at reabsorbing any water back into the blood (to a certain degree), and if you are dehydrated your urine will have very little water in it. The yellow colour is just the breakdown of bilirubin which is from the breakdown of red blood cells, and you notice the yellow color more when you are dehydrated because it is not diluted with water.

The more you are dehydrated the more the volume of your blood decreases which in turn decreases blood pressure (Hypotension). This can potentially be a bad thing as hypotension decreases your physical and mental ability. So when you are sitting at your desk and suddenly you find it hard to concentration and think it may be that you are dehydrated and you have been ignoring your basic drive to drink. Being dehydrated can shrink your brain making it harder to think and increase the incidence of having a headache or migraine, which are the last things you want while sitting at your desk.

Do your brain a favor and store and keep a BPA free water bottle on hand and at your desk at all times so you never get too busy and forget to drink.

It is not just those who sit behind a desk all day who are affected the negative effects of dehydration. Athletes who have a 2% decrease in body weight due to water loss resulted in a 10% decrease in performance.

Causes of Dehydration

Avoiding water is not the only cause of dehydration. Diseases such as diabetes can cause dehydration due to the patient having to urinate frequently, due to the excess sugar in their blood system. Diarrhetics can also block the re-uptake of water from the kidney. Diuretics include;

  • Coffee
  • Alcohol
  • Fruits and vegetables that contain high amounts of potassiumwhy should you stay hydrated
    • Pineapple
    • Lemon Juice
    • Potato
    • Sweet potato
    • Dark green leafy vegetables
    • Bananas144_-_CIMG1576
    • Green tea
    • Herbal tea
  • Medications: salt water pills and sodium absorption blockers
  • Narcotics such as heroin and morphine

After reading this list you are probably thinking that you should avoid all these things (and you should avoid the last two on the list!), even thought many of these foods on the list are very good for you.  However, with the high potassium in fruits and vegetables, the potassium purposely removes sodium from the blood stream. This is a positive reaction as the reduction in sodium causes a reduction in hypertension, it may be something to consider if you find yourself to have high blood pressure, or something to avoid if you have low blood pressure.


Functions Of Water In The Body

why should you stay hydratedOne of the noticeable functions of water is the production of sweat. The ideal body temperature should be maintained at a steady 98.6.F (37.C). The reason why the body sweats so much is to cool itself off when it is hot, which is what happens in hot weather, or physical exercise. This is why it is so important to stay hydrated when doing physical activities.

Water is also needed for metabolism of fats for energy production. Without water, carbohydrate metabolism is very inefficient compared to when there is water.  Carbohydrate metabolism is broken into two parts; glycolysis (splitting of glucose, not very efficient) and the citric acid cycle (a more general form of energy production that requires water to “spin” but produces much more energy). Whereas without water fat metabolism is virtually nonexistent.

Water also plays a vital role in digestion. Water delays the emptying of the contents in your stomach and keeps you satisfied for longer, which is why it is advisable to drink water with your meal, so you consume less food if you want to lose weight. Water also binds with fiber, that you obtain from within your own diet and creates the bulk of feces. It is this bulk that helps create a consistent flow in the gut, and prevents the reabsorption of toxins, which in turn lower the incidences of diverticulosis and bowel cancer.


Over Hydration

Although many don’t believe it is possible, you can become over hydrated. I personally discovered the effects of over hydrating recently while at my local gym. As i was waiting for my wife to finish her set on a particular machine I would mindlessly drink from my water bottle and fill it up once it was empty. I would repeat this process over the course of the gym session. Towards the end I would start to feel light headed, pale, tired and I would lose my appetite. It was not until a few gym sessions had passed that we discovered what I was doing- over hydrating myself.

Over hydration can be avoided and fixed with an electrolyte packet and monitoring water consumption while especially when working out. Although, it is not always the quantity of water that is the cause of over hydration but disrupting the internal balance of salts within the body. As you sweat and urinate, your body loses important salts such as; potassium, sodium, chloride, magnesium and calcium.

I learned that adding adding an electrolyte packet to my water helped replace these important salts and made me feel much better during and after my workout.

So if you find you are prone to over hydrating or sweating a lot you may benefit from adding electrolytes to your drink when working out.



How over hydration occurs

This simulates what happens when you over hydrate with water and don’t replenish liquid lost with adequate amounts of electrolytes.



These are our 5 tips for staying hydrated for the busy professional.

  1. Drink 5.4 fluid ounces (160ml) of water every hour if sedentary. Do not let yourself get to the point of thirst as you are already dehydrated at this point.
  2. Carry a BPA free water bottle with you at all times.
  3. Avoid salty foods for lunch or snacks.
  4. Reduce the amount of diuretics especially coffee, especially if your access to water is limited.
  5. Increase water intake in climates that are hot and dry, and possibly carry electrolyte packet as well.






Dietary Reference Intakes: Water, a. (2004). Dietary Reference Intakes: Water, Potassium, Sodium, Chloride, and Sulfate : Health and Medicine Division. [online] Available at: [Accessed 21 Mar. 2016].

Jeukendrup, A. and Gleeson, M. (2004). Sport nutrition. Champaign, IL: Human Kinetics.

Kempton, M., Ettinger, U., Foster, R., Williams, S., Calvert, G., Hampshire, A., Zelaya, F., O’Gorman, R., McMorris, T., Owen, A. and Smith, M. (2010). Dehydration affects brain structure and function in healthy adolescents. Human Brain Mapping, 32(1), pp.71-79.

Toker, J. (2009). The Math of salt loss. [online] Available at: [Accessed 25 Mar. 2016].



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