Why we need water and how much?

Hello everybody! Welcome back to my blog. The purpose of this blog is to help people find their way to a healthier lifestyle. I mostly talk about exercise, nutrition and the science behind them, which are my areas of expertise, but I also talk about sleeping habits, minimalism and many other subjects related to wellbeing and healthy lifestyle. 

Today’s post is a little introduction to our most essential thing, something we can’t survive without for more than 2 or 3 days: water. Water can be sourced from water itself, from other drinks such as tea, and there are also certain foods which contain a fair amount of water, like our fruits, vegetables, yogurts, or soups.

Our body is made of around 60% water. All over our organism there’s water: it represents more than 70% of our heart and brain, more than 80% of our lungs, around 80% of our muscles, and so on. It’s in every organ, bone, as well as in our blood. It’s also part of our skin, making up more than 60% of its composition.

Just a drop of 2% of water in our body can lead us to suffer from headaches, an increase in our body temperature, dizziness and nausea, thirst, a decrease in our blood pressure, lethargy and tiredness, and a deterioration of our cognitive functions. All these are signs of dehydration. Dehydration or a minimum drop of our water levels can even lead to weight gain as it’s commonly mistaken by with hunger, making us eat more calories.

Water plays many key roles in our body: temperature regulation, swallowing aid, cells lubrication, supplying a medium in which most of the chemical reactions happen, transporting water soluble vitamins (all B vitamins and vitamin C), transporting nutrients around the body in the blood, just to mention a few.

Water also carries waste out of the body. In our faeces and urine there’s water alongside with all of the unwanted remains our organism produces through respiration and food intake.

This is why it’s so important to stay hydrated and constantly replace the water in our body so that the decreased levels of water once we’ve excreted it can be restored. Nonetheless, a higher level of water than normal is not desired. That is why our body secretes the excess water through urination, which happens more often when more fluids are consumed. Remember that otherwise healthy people’s organisms are perfect machineries that know when they need to balance themselves up (a phenomenon known as homeostasis) and will let us know through signs such as pain, discomfort, or evacuation. When we are lacking water, our body sends thirst signs, and even if we ignore this sign, it will make it obvious through other channels such as urine colour.

The same happens when it has been overfed with water. Our body will pressure the bladder creating the urgency to urinate. If we ignore this sign, it can get to be very painful and it’ll evacuate eventually.

So the big question is, how much water do we need per day? The answer to this question is, as it’s for everything else, it depends: on age, weight, climate (hot and humid), the work we do (construction worker or office worker) and, of course, physical activity levels.

The amount of water required would increase for those living in hot and humid environments, who are physically active through their lives, and for those who participate in regular exercise where excess fluid may be lost through sweat. On the other hand, fluid requirements may be lower for some individuals such as those who are sedentary or the elderly, who are less active and may consume more water based foods such as soups as they not longer have strong teeth to bite and chew harder foods.

In general, the EFR (Estimated Fluid Requirements) are 30-35 ml per kilogram of weight. For example, an average person who weights 60 kg will need 1,800-2,100 litres of water per day, without taking into consideration all of the factors we mentioned before. If this person is a 25 years old woman who lives in Sydney and runs 10 kilometres 4 to 5 days a week she will definitely need more water than just 1,8 to 2,1 litres (especially during the summer months).

Calculating how much this individual would need is not that simple, but it’s not impossible. There are some formulas that a dietitian or nutritional advisor can use to determine how much water this young women needs to ensure a correct reposition of water without compromising her health and performance, and even by doing this, every time she goes for a run, the amount of water lost and therefore the amount required would be different. To calculate it, we need her weight before and after the training session as well as any liquid or solid intake during the session so that we can determine the amount of water she needs to replenish.

That’s it for today! I really hope that you enjoy it. If you like what I do and you want to support this project, follow me on Instagram and Facebook, like the post and comment! Should you have feedback you’d like to leave, a comment to share with me, or a cool idea for a post, send me an email to sanchisayslifestyle@gmail.com

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