Do animals even drink or need as much water as we do in order to be healthy?? Why do we need so much?
In: Biology
The short version is that we continually lose water, even when we’re relatively inactive. Every time we exhale, we breathe out a bit of water vapour. We need to excrete some water through our digestive systems to carry toxins out of body. We perspire – even on colder days, we are generating sweat. Also, our metabolisms use water in the various processes associated with food digestion.
In answer to your first question, animals do sometimes need a lot of water to stay healthy. It depends on temperature, body size, metabolism, and the same factors that influence our need to drink water.
You say we need so much, but how much do you think that is?
You can get water from many sources, for example, from any drink and from fruit and vegetables. You don’t need to drink it as plain water.
In total, for your water from *all* sources, you only have to have enough to keep your pee light straw coloured. That’s around just over a litre for most people. Usually, that just means having a drink when you are thirsty.
However, there are lots of myths around drinking plain water:
* That you need to drink 6-8 glasses of it per day
* That the more you drink the better
* That it will somehow ‘flush out your kidneys’
* That you can’t harm yourself by drinking too much (very rarely, drinking too much can be fatal)
We don’t. Tik tok might be saying you do to sell you a fancy AirUp bottle but you need roughly 1.2l a day and it doesn’t have to be water. Your body takes water from food and any drink water obviously better than anything with calories or nasty flavourings but you really don’t need buckets of it.
Animals all perform a process called respiration. During this process, we use oxygen and glucose to make a molecule called ATP. The products of making ATP are carbon dioxide and water. This set of chemical reactions almost certainly evolved the way they did because animals started out ***in water***. Water is super convenient for many reasons, it’s a great solvent for most molecules, it has protons it can give up or accept pretty readily so you can do some neat chemistry with it, it takes ***a lot*** of energy to change its state AND it’s liquid in a range where other molecules can interact and chemically change. It’s the perfect liquid to start life in!
About a half a billion years ago, animals started to move onto land (right after plants). The primary difference between water and land is the water. You don’t have a source of water immediately available 24/7. So many of the chemical reactions animals rely ‘assume’ that water is plentiful. Evolution can’t just change these reactions, they’re so fundamental to life that any alteration is probably going to be bad. So, evolution ‘worked’ by creating mechanisms to try to retain water in the water. Animals developed water-proof skin, our urinary systems developed methods for concentrating nitrogen waste products like urea while retaining water, etc. But the fact of the matter is that water is **required** for some things. First, we need water to dissolve oxygen, so we can move oxygen from the lungs into the blood. This is a physical limitation that can’t be overcome. And so our lungs are coated with water and every time we breathe out, we lose water. Our digestive system won’t function if we don’t add water to our food. The water helps dissolve food molecules and allows our enzymes the ability to break down those molecules AND absorb them properly. In humans, we need a certain amount of water in our feces to defecate properly. Too little water and we become constipated and retain our feces (which will have all sorts of bad side effects). Evolution can’t overcome these basic physical constraints, so it “works” to lessen them, but it can’t **eliminate** them. Therefore, we lose water and need to constantly replace it. Some animals are better at water retention than others (compare humans to camels) but all animals will lose water to the atmosphere and urination and need to replace it via ingestion of fluids.
Mostly through your kidneys that use it to filter your blood and other physiological processes that you don’t really notice. One example are mucose membranes ( you could have heard of them while talking about upper respiratory system issues ), their job is to protect the tissues from drying out by secreting mucus, and mucus is in part made by water. Digestion as well as absorbtion of nutrients require water too.
When they say that water is life, it’s actually true, most if not virtually any organism and their internal processes to survive require some water to get done.
Is your question based on how much water humans actually *need* to consume from all sources, or the absurd amounts we are told humans *need to drink* as straight water? Those are two different things, and I think the answer will be different depending on which you mean.
We sweat. Dissipating heat is one of our evolutionary advantages that contributes to our endurance. We can’t catch a cheetah. But we can outlast them in a marathon
We absolutely do not need as much water as people decided over the past 5-10 years. You can blame the “wellness industry” for that nonsense
A huge amount of water is just peed out again. But this is necessary to remove metabolic toxins from our body.
We need to drink enough water to remove these toxins while also maintaining our water levels for biological processes, maintaining circulating volume and the appropriate dilution of other biological substances
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