The Water-Hydration Myth

During a recent seminar someone asked me, “How much water do you drink each day?”.  They gasped when I said I drink one glass a day, sometimes two.  I also mentioned that it depended on the day.  If I sweat, exercise, or feel thirsty, I drink more.  Also, that is ‘water’ ingestion…I drink other fluids in the form of green tea, coconut milk, and kombucha.  No, I don’t get thirsty. No, my urine isn’t totally clear. No, I’m not going to die of dehydration!  As a matter of fact, it is a MYTH that we all need 6-8 glasses of water per day.

That got me wondering, where did this myth come from?  To me it makes perfect sense to drink when I’m thirsty and that our ancestors survived just fine (they were actually stronger, healthier, taller, and had less cavities…but that’s another post), without guzzling gallons of water. I discovered that this is another one of those ‘flawed conventional wisdom”  concepts that gets construed as truth by the sheeples (you know, those people that just follow the crowd and don’t bother to think on their own).

After much digging, all I could come up with, to even remotely support this theory, is that the water myth was first mentioned by Dr. Fredrick Stare, founder of Harvard’s Department of Nutrition. He wrote Nutrition For Good Health in 1974 in which he said:

How much water each day? .. for the average adult, somewhere around 6 to 8 glasses per 24 hours”.  But as I read further I found he clarified this statement with, “…this can be in the form of coffee, tea, milk, soft drinks, beer, etc. Fruits and vegetables are also good sources of water”.  

More recently, Heinz Valtin, with the Dept. of Physiology at Dartmouth Medical School, states in a paper written in 2002:

“...caffeinated drinks (and, to a lesser extent, mild alcoholic beverages like beer in moderation) may indeed be counted toward the daily total, as well as by the large body of published experiments that attest to the precision and effectiveness of the osmoregulatory system for maintaining water balance.” and he continues, “the warning that dark urine reflects dehydration is alarmist and false in most instances.”

In other words, we can get our fluids from many sources, and our bodies are very adept at regulating its balance. Heinz Valtin also concluded that no scientific studies support drinking 8 glasses of water per day if you are a healthy adult living in a temperate climate and doing mild exercise.  In fact, he found that drinking this much could be harmful.

This over-consumption of water is called hyponatremia.  I have seen this happen in athletic events.  The symptoms closely mimic dehydration so the participant drinks even more water, confounding the problem even more. This study, in the Clinical Journal of the American Society of Nephrology, states 13-29% of endurance competition athletes suffer from hyponaturia.  This doesn’t mean you shouldn’t drink water during endurance events, just be aware that if you feel like you have been ingesting enough water, but you are having dehydration-like symptoms, it could be hyponatremia and it could be fatal.

Here are some symptoms of “over-hydration”:

  • Nausea
  • Vomiting
  • Headache
  • Confusion
  • Fatigue
  • Muscle Weakness
  • Cramps
  • Cold hands/feet
  • Bloating of hands, legs, and feet

What about the ‘fact’ that caffeine dehydrates the body and can’t be counted as fluid?  According to Spero Tsindos, in this article which appeared in the Australian and New Zealand Journal of Public Health 2012, this is another myth.  He states:

We should be educating the general public that beverages like tea and coffee, despite their caffeine content, do not lead to dehydration and will contribute to a person’s fluid needs.”

So what is the smart way to drink water?  Not falling for the marketing of companies like “Smart Water”, that have a vested interest in convincing you that you need more, is a good start.  If you are thirsty–drink.