When asked how much water one should drink a day, most people will say they need 8 glasses. However, recent studies show that this is actually not likely the case.
Just as general nutrition advice and even the food pyramid has changed over the years, so too has advice as to how much water one should drink. In fact, the exact origins of this advice are still fuzzy to this day.
For example, even though some of the most recent evidence points to this advice having first been given by doctors in the 1940s, it is highly possible it originated as far back as the 1700s.
As with most health advice that dates back to such a time, it is easy to see why it might be considered to be outdated today. Given the advancements in physiology the world has made at large, as well as the knowledge we have today, we have a better understanding of just how much water we need exactly.
Why this has been largely disregarded as of late is due to a wide number of factors. One such factor, in particular, is the fact that most foods we consume contain a fair amount of water.
This statistic includes far more than vegetables alone. Fruits and cooked meats also contain a large amount of water that is often not taken into consideration when determining how much water one should consume.
Another argument that has been posited in recent years is that one should not hold oneself to drinking a certain amount of water daily at all. This idea posits that the body intuitively knows when it is in need of extra water. Because of this, listening to our own thirst cues is the best way to determine when one should drink water.
Learning to pay attention to these cues and simply drinking when thirsty is now touted as one of the best ways to drink water. Put simply, one should just drink when they’re thirsty and not force themselves to drink water when they’re not.
The one drawback of this method is that unless you are used to doing it, it comes with a learning curve. Listening to your own body’s natural thirst cues takes practice and skill if one is used to ignoring them. However, once one has practiced doing so for a while, it will likely become part of one’s second nature.
Another theory posited is that many adults get a large number of their daily fluids from many other liquids. Many adults begin their day with a cup of coffee or tea and continue drinking these liquids throughout the day. While some may cite caffeinated drinks as sources of dehydration, they do still contribute to the amount of one’s daily water intake.
Combining these liquids with the foods we eat in a day makes it so that we are ingesting a lot more water than we think we are.
Taking all of this into consideration, there is one major reason why eight glasses a day cannot be a one-size-fits-all answer to the question of how much water one should drink in a day. Put simply, there should be no one-size-fits-all solution because of the differences between body mass among the general population.
The amount of water one needs to drink in a day directly correlates with one’s body mass. A larger person will generally require more water in relation to a smaller person. Because of this, newer advice typically suggests men drink more water than women, due to their average difference in body mass.
Following this, people typically require more water when they are being active versus when they are being sedentary. In order to combat water loss due to sweating while performing physical exercise and avoid dehydration, one must typically increase the amount of water one drinks.
It is clear that a variety of lifestyle and personal differences all contribute to the overall amount of water one must drink in a day to avoid dehydration. When in doubt, drink when you are thirsty and avoid forcing yourself to drink water when you are not.