July 2008 - Vol 3 Issue 7

The Great Water Debate
How much water do you really need?
by Michelle Gibeault Traub, R.D.

You have probably heard the recommendation to drink eight, eight ounce glasses of water a day. I’ll admit for years I would tell my patients to do just that - a suggestion which was frequently met with gasps or sighs that made it very clear that the average person is overwhelmed by that goal. If you are among those who have struggled to drink your eight daily cups of water, you may be able to rest a bit easier as some physicians are now arguing that water needs are not “one-size-fits-all.”

Different Bodies, Different Needs
There are a multitude of factors that impact a person’s individual fluid needs – from concrete factors like age, weight, height, and genetic make-up, to more variable aspects like overall health, and environmental conditions. Given these differences, it is not hard to believe that each of us may have our own personal fluid requirement. So, while some people may in fact need eight glasses of water every day, chances are most do not. But, brace yourself – there is a very good chance that some of us actually need even more.

Eight is Just an Estimate
So, if eight isn’t the magic number for water needs, how do we actually know what we should be drinking? Unfortunately, there isn’t an easy answer. This is likely why the "8 x 8 rule" has been so popular – simply because it made an otherwise complicated issue a little easier to manage. However, after careful review of the scientific literature, researchers from the University of Pennsylvania recently determined that there was no real basis for such a general recommendation. Regardless, given the fact that the average adult loses around 10 cups of water daily through their breath, sweat, feces, and urine, along with the estimate that most people meet 20% of their fluid needs through food; drinking 8 cups of water seems to be a pretty reasonable guideline. Still, it is just that - a guideline. Additional guidelines established by the Institute of Medicine take into account all beverages (including juices, coffee, tea, etc.) and suggest that men should drink approximately 13 cups of total fluid and women should drink around 9 cups of total fluid every day. Wow! And you were overwhelmed by 8?

Your Body Will Tell You What You Need
It is all a bit confusing. But, the good news is that your body does provide some clear indicators of what is best for you. Thirst is an obvious sign that your body needs more fluids, and a clear warning that you need to drink. But it isn’t always the most sensitive indicator, especially for older adults whose thirst mechanisms are not as sharp. This means that some older individuals don’t truly become thirsty until they are near dehydration. This can be dangerous because it is easier to prevent dehydration, than to try to catch up on fluids when you are already running low. A better means of assessing your fluid intake is through the color of your urine, with clear or pale yellow urine indicating a healthy fluid balance, and dark yellow or amber urine indicating dehydration. Another way of assessing your hydration status is simply by how you feel. Thirst, dizziness, confusion, fatigue, fever, and dry mouth are all symptoms of dehydration.

Water Works Wonders
You might be thinking, “What’s the big deal?” This seems to be a common response for most people, as we often take water for granted. That is of course until we are at a ball game or an amusement park, feeling parched, and our only option is to buy a four dollar bottle of water. Then, we realize just how valuable water can be! But, its value goes well beyond the amount that we shell out per bottle. The real wonder comes from all of the essential roles that water plays in the body including aiding with digestion, elimination, blood flow, and temperature regulation just to name a few. If you are not well hydrated, your body can’t work as efficiently, and you simply won’t be at your best.

Tips for Meeting Your Daily Water Needs
Although determining your fluid needs can be a bit of a challenge, actually meeting them doesn’t have to be. Here are a few tips:

• Fill a pitcher with 6-9 cups of water (based on you own personal needs) every night before going to bed and put it in the fridge to chill. When you wake up, start you day with a big glass of cold water, and continue drinking from the pitcher throughout the day until it is gone.
• Add slices of citrus fruit to your water (lemon, lime or orange) to give it a little extra flavor with no extra calories.
• Eat juicy foods like fruits and vegetables including melon, grapes, tomatoes, lettuce, and squash.
• Dilute juices and soda with 25% water, gradually increasing to 50% water as your taste buds adjust.
• Cool off beverages like coffee, lemonade, or tea with lots of ice cubes.
• Limit alcoholic beverages because they are diuretics and actually increase your fluid needs.

When the heat is on, make water your first choice. Instead of worrying about how many cups you should be getting, pay more attention to how you feel. By drinking regularly and staying ahead of thirst, you are sure to get the amount that is just right for you, no debate about it.

References

• Dan Negoianu and Stanley Goldfarb. Just Add Water. J Am Soc Nephrol. 2008; 19: 1041-1043.


• Mayo Clinic Staff. Water: How much should you drink every day?  MayoClinic.com. April 19, 2008. retrieved 7/21/08 LINK


• Mayo Clinic Staff. Dehydration. MayoClinic.com. Jan. 3, 2007. retrieved 7/21/08 LINK

Top of Page