Our body’s essential functions are fueled by water so it’s no surprise that the average human can only live a mere three days without it. Water is everywhere but even though fluid intake suggestions for daily life have evolved over time, there is still no true consensus about how much water we should all drink. Our bodies are made up of 60% water. How much fluid we lose through our skin, through breathing, stool and urine is determined by our basic metabolic demands. Fluid loss is often measured inaccuratley by looking at activity or frequency of urination when in fact the best estimate of our hydration is thirst. I question whether or not true thirst is ever realized in someone who consumes more than 64 ounces of fluid per day. What science has shown us with athletes is that thirst not water loss may be the signal that impacts exercise performance.

I was told to drink 8 glasses of water everyday

Overall, there is no scientific evidence that states we need eight 8 oz. glasses (64 oz.) of water each day, yet thermoses filled with water is omnipresent amongst teenagers, young professionals and middle-aged women, touting myths about great skin and good bladder health. What’s important to note is that higher fluid intake beyond 2.2L has not been shown to improve health outcomes, except in patients who have medical conditions like kidney stones.

Drinking water should be individualized

Like many other health fads, it is imaginable that that the concept of large volume consumption is outdated and oversold.  Clearly everyone has different fluid needs, if you’re an NBA athlete then you will need to drink more water than a high school history teacher. Blanket hydration advice is easy to promote especially when paired with decades of great marketing. Hydration needs should be individualized and currently the best judge of hydration is thirst. So, the overarching answer to the question, “How much water should I drink?” is to let your thirst be your guide.

Tips to promote health drinking habits 

• Avoid beverages that may be diuretics (fluids that promote urine loss): Large amounts of caffeinated beverages like coffee and alcohol may stimulate the kidneys to produce urine which may lead to dehydration. 

• Drink when you are thirsty: In 2004, the Institutes of Medicine reported that most people meet their daily hydration needs by letting their thirst be their guide.

• Eat lots of fruit and vegetables: We get additional fluids from our diets in the form of soups, stews, fruits, etc. It has been shown that we get as much as 20% of our daily fluids from our diet. Eating more fruits and vegetables will contribute to your overall fluid intake. 

• Choose a smaller water bottle: Yes, drinking smaller amounts more frequently will help you to avoid over drinking and will also help counter bothersome issues like urinary frequency or urinary incontinence.