The idea behind this idea is to keep ourselves hydrated. This way we stay healthier, help expel toxins from our system, keep from becoming dehydrated due to sweating, and so much more. It turns out that the human body is quite inefficient because we are always losing moisture, cannot store the excess, and we cannot replenish it. We cannot go for any real length without water. We are always losing water through our urine and via sweating or via our breath.
According to what I can find out, this particular notion first made its appearance back in 1945 when it was published as part of nutritional guidelines established by the Food and Nutrition Board of the National Academy of Sciences. They suggested that people needed this amount of water every day even though there were no studies published to support this claim.
According to several nutritionists and scientists, most people get way more than the recommended intake if you include all the moisture in the food we eat and the liquids we drink directly. There is water in most foods even if we are not really aware of it and that liquid makes up part of our daily requirement. Furthermore, if you are not getting enough liquid, your body tells you by letting you know you are thirsty.
However, if hot weather, you are likely to need more hydration so we need to be making sure we get extra moisture. Also, as people age, the thirst reflex decreases so older people tend to become dehydrated more easily. My mother would always make sure she and dad had glasses of water with them all day long because she'd easily become dehydrated.
In general, if you drink more water than you need, you will expel the extra through your urine because your kidneys are designed to maintain a balance between water in and water out. There is research that indicates drinking excess water provides no benefits but if you have certain medical conditions such as heart disease or kidney disease, your. body may retain more than it should and this can cause problems.
So if you are not drinking eight glasses of water a day, do not feel bad. Follow your body and if you are thirsty, drink something, if not, don't worry. One rule I learned years ago when I had to work outside on extremely hot days is one I use. If your urine is dark, drink more, if it is a nice light yellow to clear, you are fine. Let me know what you think, I'd love to hear. Have a great weekend.