Water, How Much is Too Much?

Source: Do You Really Need Eight Glasses of Water a Day?

How many of you have heard that we are dehydrated and need to drink at least eight eight-ounce glasses of water a day? I know that is what I have traditionally been exposed to.

I used to advise that people follow an even more refined rule of thumb--for every 50 pounds of body weight you carry, drink one quart of spring or filtered water per day. This would increase daily water intake to 12 to 16 glasses for most of us.

However, after awhile I began to question this and I further refined my recommendations to use the color of your urine as a guide to how much water you should be drinking.

As long as you are not taking riboflavin (vitamin B2), which fluoresces and turns your urine bright yellow (it is also in most multi-vitamins), then your urine should be a very light-colored yellow. If it is a deep yellow then you are likely not drinking enough water.

So I was delighted to read in my Family Practice News that an Institute of Medicine Panel actually reached the same rational conclusion.

They rejected the conventional wisdom that people need to drink eight glasses of water a day and concluded that on a daily basis people get enough water from normal drinking behavior, such as drinking beverages at meals and in other social situations, and by letting their thirst guide them.

Let Your Thirst be Your Guide

When your body begins to lose from 1 percent to 2 percent of its total water, your thirst mechanism lets you know that it's time to drink some water.

If you are healthy, then drinking whenever you feel thirsty should be an adequate guide of how much water you need. You can confirm whether you are drinking enough water by looking at the color of your urine, as mentioned above.

Of course, if it's hot outside or you are engaged in exercise or other vigorous activity, you will require more water than normal so be sure to stay well hydrated in these cases.

Additionally, as we grow older our thirst mechanism works less efficiently so older adults will want to be sure to drink water regularly, and again make sure their urine is a light, pale color.

Another Reason Why Women Can Retain Water

Explains Why Too Much Water Can Harm Marathon Runners: Source

When runners collapse or get sick at the end of a long race, it seems logical to give them fluids. Sometimes, however, water is the last thing these athletes need. All had taken in too much water during their races, causing sodium levels in the blood to drop.

From there excess water is absorbed into blood and fluid builds up in the brain. Eventually, fluid accumulates in the lungs, and athletes become breathless and nauseated.

When runners collapse or become ill, the natural assumption may be that they are having a heart attack. Yet, rather than being a sign of heart attack, fluid build-up in the lungs -- called pulmonary edema -- may signal brain swelling.

The investigators describe the cases of seven marathoners who collapsed and had nausea and vomiting after their races. When brain scans revealed swelling, six of the patients were treated with an intravenous solution containing high amounts of sodium -- a water-depleting treatment that is directly the opposite of the low-sodium solutions that runners may receive if they are misdiagnosed.

The seventh patient, who was not diagnosed with brain swelling, later died; an autopsy revealed that there had indeed been fluid on the brain.

Five of the patients were female, suggesting that women may be more prone to water intoxication and its effects on the brain and lungs. All seven had a history of using nonsteroidal anti-inflammatory drugs -- painkillers that include aspirin.

These drugs can block the excretion of water from the body. Runners who become breathless and nauseated after drinking large amounts of water during a race should go to the hospital and doctors should check blood sodium levels.