Body of water

Philip J. Goscienski, M.D.

June 2012

Most of the earth's surface is made of water — and so are you. In fact, the day you were born about 80 percent of your body weight consisted of water. That number goes down through the decades so that by the time you qualify for Medicare, about 60 percent of your weight is water.

If you wonder why your skin has gotten more wrinkles or you're an inch or two shorter than you were in high school or even why you can't hold your liquor so well, water — or the lack of it — is the reason.

Dehydration occurs when the intake of water doesn't keep up with outgo. This is a well-recognized hazard among the elderly, especially during a heat wave or illness. Normally our thirst mechanism tells us when we need to drink more but that sensation begins to diminish as we age. Elderly persons are often slightly dehydrated because of this and it leads to weakness, fatigue and confusion. Diuretics are drugs that are commonly prescribed among seniors for the treatment of high blood pressure. They increase loss of fluid through the kidneys, adding to the risk of dehydration.

As we get older our skin's water content diminishes so that wrinkles appear. Purveyors of anti-aging skin products claim that rehydrating the skin gives it a more full appearance so that wrinkles aren't so prominent. On the morbid side, persons who develop edema, the excess fluid in tissues because of congestive heart failure or kidney disease note that the skin appears smoother as it retains water.

As we get older we're likely to get shorter. The bones that make up our spinal column are separated by spongy intervertebral discs that, like the rest of our body, contain less water as the years go by. Thus they become more compact. If each of these 23 cushions decreases in height by only a tenth of an inch it amounts to about two inches.

If the percentage of body water diminishes between the time you leave high school and receive your first Social Security check it helps to explain why a couple of drinks leave you with more of a buzz now. There just isn't as much water in your body to dilute the alcohol.

The color and odor of your urine are the most reliable markers of hydration. It should be pale yellow with only a slight odor.

Philip J. Goscienski, M.D. is the author of Health Secrets of the Stone Age, Better Life Publishers 2005. Contact him at drphil@stoneagedoc.com.