Drinking water poured into a glassIt may come as no surprise for me to tell you that water isn’t a food. To be so it would need to contain organic nutrients such as protein, fat and carbohydrate, or provide energy—which it doesn’t. But if it was a food, water would be the most super food of all. No living thing can survive without water and almost everyone would benefit from drinking more of it. Without water, there would be no life.

Around 60% of the human body is made up of water(1). Different parts of the human body contain more water than others, the lungs are a whopping 83% water, skin is just 64% and our bones contain 31% water(2) even though we think of them as being hard and dry. Babies and children have a higher percentage of water in their body than adults, men have more water (as a percentage of total mass) than women because men typically have less body fat, and fat contains less water than muscle(3).

I’m probably as bad as the next person for not drinking as much water as I should, although I’m pretty sure I’ve got a lot better over the past few years. I used to be the guy who would feel sleepy in the afternoon and head for my umpteenth coffee of the day, or worse still—a sugary energy drink. But more often than not, my body was craving water and not caffeine, taurine or sugar.

I still feel the temporary effects of mild-dehydration occasionally, but I’ve become better at spotting the tell-tale signs and addressing the imbalance. I always have a bottle of water on my desk—I guess throughout the day I drink between three and four litres of water (not including coffee or other drinks), yet I don’t obsess over the number of glasses or litres I’m drinking. When I wake up, I drink a big glass of water straight away (after weighing myself). When I feel sluggish, I take on more water and wait twenty or thirty minutes before deciding whether or not I need some coffee too—if I can avoid it I will, saving caffeine for those times I really need a kick to get me going. If my urine has a strong yellow colour when I pee, I will also make a point of drinking more water. I’m no expert or shining example, but these are simple indicators I use to evaluate whether or not I’m drinking enough and feeling my best.

What’s so bad about being dehydrated?

Quite a lot actually. Dehydration itself is easy enough to understand—simply not replacing water expelled by the body. Whether water is lost through passing urine, sweating or any other method, it simply has to be replaced. It’s understood that a drop of just 1-2% from ideal levels of hydration will produce noticeable effects, as we begin to feel thirsty, lose concentration and crave a drink(4).

Dehydration matters pictureThe early stages of dehydration might include a dry mouth, feeling drowsy and the onset of a mild headache(5). If you don’t drink some water now, it could quickly develop into a more serious condition where you might suffer from the discomfort of constipation, muscle cramps or dry skin. Failure to act then would rapidly lead to the more extreme conditions of low blood pressure, fever, a rapid heartbeat caused by additional stress being put on your cardiovascular system because your heart is pumping thicker blood and eventually unconsciousness as your body starts to shut down(6). It might sound extreme, but water really is that important.

If you’re feeling thirsty whilst reading this, you’re probably already a little dehydrated—but don’t worry, have a glass of water and you’ll feel better soon. Most people never suffer from the extremities of dehydration but imagine the positive impact of just drinking a little more water each day. It’s free, readily available and easy to consume—there is literally no excuse for not drinking more water and when you consider the positive impact it could have on your health and life, why not?

What’s so great about water?

Aside from the obvious uses such as washing, cooking and drinking, water is essential to create and sustain life in all forms. We know that much of the human body is made up of water, but what does it actually do in our bodies? Water acts as an insulator, regulating the body’s temperature much the same way as engine coolant in a vehicle. It lubricates joints and acts a form of insulation around the brain, spinal cord and vital organs, like a shock absorber(7). Water is needed to metabolise proteins and carbohydrates used as food, it flushes waste and toxins from our body through the processes of urination, perspiration and defecation(8). Drinking adequate water aids digestion and prevents constipation(9), staying hydrated helps maintain mental agility and peak physical performance. All in all, water’s a pretty magical substance.

Water can be neither created nor destroyed, it is in a continuous sequence known as the hydrological cycle between being underground, on land or in the atmosphere in its various states of liquid, solid and gas. There’s a lot of water on planet Earth (236 million trillion gallons)(10), although only around 1.1% is suitable for human consumption(11). But that’s still a hell of a lot of water—so there’s no need to worry.

How much water should I drink?

FitKno cat drinking water from a tapThe European Food Safety Authority (EFSA) recommends a minimum daily intake of 2 litres for women and 2.5 litres for men(12). However, this is dependent on a variety of factors, such as the ambient temperature and your level of activity. Clearly in hot weather or when exercising you’ll need to drink more. Each of us has individual needs, it’s up to us to monitor how much we’re drinking. These are just guidelines which should be paid attention to, but not religiously adhered to. Remember that these quantities are a minimum, you should never think ‘oh I’ve already drunk two litres today, I’d better not drink any more’.

As with other forms of consumption, it is possible to drink too much water, but our kidneys are capable of excreting a litre an hour or around 20 litres of fluid a day (13)—although it’s doubtful you’ll be drinking more than that. Drinking too much water can (rarely) result in a condition called hyponatremia, otherwise known as water intoxication, where so much water is consumed the level of sodium or salt in the blood drops to dangerous levels(13a). Most healthy adults can cope with drinking a lot of water, you’d need to be drinking litres of it every hour to cause problems.

Drinking when exercising

Staying adequately hydrated during exercise is essential. Because we’re putting our bodies under more pressure than normal, failing to drink enough will quickly result in a rise in core temperature, a lack of clarity and the cardiovascular system having to work harder than usual. This is because having less water in your body means your blood is slightly thicker—causing your heart to work harder to pump the same amount of blood around your body. If you want to work out at anywhere near your peak performance level, it’s essential you maintain a proper level of hydration. It’s commonly understood that if you’re exercising for less than 60 minutes, then simply drinking water will be enough to maintain adequate hydration(14). But if you’re planning to work out for over an hour or in very hot weather—consuming a sports drink such as SIS Hydration Tablets or Saltstick Capsules which contains calories and electrolytes is recommended(15). We know what a calorie is, a measurement of the fuel in food which gives us energy, but what’s an electrolyte?

Electrolytes are a collection of electrically charged minerals such as calcium, potassium and sodium, which are essential to the biochemical processes which take place within our bodies. Electrolytes help to maintain healthy blood pressure and the proper functioning of the heart, muscles and the central nervous system(16). Electrolyte depletion can cause muscle cramps, headaches and a significant loss of performance.

FitKnow, water, what's in it for us?Obviously, it’s possible to drink too much when exercising and you need to find out what works best for you. If I’m running less than 5K I might not drink at all during my run, because it’s short enough not to need to. Running 10K or longer, I’d take regular sips from a hydration pack and try not to stop and gulp down half a bottle of water, because this would then be sloshing around inside my stomach and cause discomfort. For long runs, my preference is to sip water during exercise and then have an electrolyte drink immediately after I finish. If I have been running for over an hour and skip the electrolyte drink, I’ll soon develop a crippling headache which could have been easily avoided. Find what works for you and helps you to feel fresh and energised throughout your workout.

Does only water count?

Not at all, milk, tea, coffee and sugar free drinks all help to maintain your hydration levels(17). Sugary drinks contain a lot of calories, so should be limited or monitored. It may come as a surprise that around 20% of our daily water intake comes not through what we drink but what we eat. Clearly foods such as soup or fruit and vegetables all contain a high percentage of water(18), but so do some bakery products, fish and meat. Whilst there are recommendations of how much water to consume throughout the day, I don’t see calculating your intake as important as doing so for calories or protein etc. The rule of thumb should be that you know when you’re feeling your best and when you need a pick-me-up. If you need a little boost, why not drink an extra glass of water before going straight for the coffee (or worse, energy drink)?

The last word

Along with getting enough rest and adequate nutrition, staying hydrated is one of the most important things we can do in life. In order to stay in top form, why not follow these simple points:

  • Carry a bottle of water with you, always keep a drink close by at work.
  • Give more thought to how much water you’re drinking, use a tracking app if it helps you.
  • Drink a glass of water first thing in the morning and with every meal.
  • Look out for the early signs of dehydration and act immediately.

Following these simple points will help keep you healthy and feeling alert.


(1). https://water.usgs.gov/edu/propertyyou.html
(2). https://water.usgs.gov/edu/propertyyou.html
(3). https://water.usgs.gov/edu/propertyyou.html
(4). https://articles.mercola.com/dehydration-symptoms.aspx
(5). https://articles.mercola.com/dehydration-symptoms.aspx
(6). https://www.medicalnewstoday.com/articles/153363.php
(7). https://www.thoughtco.com/how-much-of-your-body-is-water-609406
(8). https://www.healthline.com/health/food-nutrition/why-is-water-important#lubrication
(9). https://www.healthline.com/health/food-nutrition/why-is-water-important#lubrication
(10). https://science.howstuffworks.com/environmental/earth/geophysics/question157.htm
(11). https://www.health24.com/Diet-and-nutrition/Beverages/12-interesting-water-facts-20120721
(12). https://efsa.onlinelibrary.wiley.com/doi/epdf/10.2903/j.efsa.2010.1459
(13). https://www.medicalnewstoday.com/articles/318619.php
(13a).  https://www.webmd.com/fitness-exercise/features/water-intoxication
(14). https://www.bupa.co.uk/health-information/exercise-fitness/hydration-exercise
(15). https://www.runnersworld.com/beginner/a20809258/what-should-i-drink-while-exercising/
(16). https://www.active.com/nutrition/articles/runners-electrolytes-and-when-to-replace-them
(17). https://www.bbcgoodfood.com/howto/guide/how-much-water-should-i-drink-day
(18). https://www.nutrition.org.uk/healthyliving/hydration/healthy-hydration-guide.html

Comments (2)

  • A winter cold – FitKno

    15th May 2019 at 8:19 pm

    […] My first priority would be rest, which means that training is off the agenda for at least the next five days. As much as I’d love to continue the progress I’ve been making, I need to be sensible—there is little point in working out if it’s going to delay my recovery. Excellent nutrition is a top priority, eating as much fresh fruit and vegetables as I can will help me fill my body with nutrients and aid my immune system fight this horrible feeling I have right now. It’s also important to stay hydrated, so I’ll be drinking lots of water to try and flush the virus out and ensure I don’t suffer addition symptoms from becoming dehydrated. In my experience, it’s always better to drink more water than less, particularly so when not feeling too good. You can read more about adequate hydration levels in my article: Water, what’s in it for us? […]

  • Holiday Eating – FitKno

    17th May 2019 at 12:02 am

    […] Staying adequately hydrated will help digestion and ensure the energy you’ve consumed is burnt as fuel rather than stored as fat. Drinking lots of water also keeps you alert and feeling on top of your game. When you’re out and about exploring new places, it’s quite easy to forget to drink as much as you need. So, always carry a bottle of water and enjoy the best energy drink there is. For more information on maintaining adequate hydration, why not read my post ‘Water: What’s in it for us?’ […]

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