March 11th, 2009
01:27 PM ET

There's more to exercise

By Leslie Wade
CNN Medical Producer

I don't think I ever walked much as a kid. I mostly ran. I was a tomboy with an older brother and running and playing outdoors was my MO. So why am I finding it so hard to exercise now that I'm over 50? Maybe it's because an ankle injury has limited me to walking. We all know that exercise is the key to living a longer healthier life. Why don't these words propel us out of bed each morning reaching for the running shoes? It helps me to know WHY something is so before I do it, and exercise is no exception. Let me take you through a rudimentary physiology lesson. I promise I won't get too nerdy.

Sticky and yucky, no thanks – You probably know, there are 2 types of blood cholesterol, the good, called the HDLs, and the bad, the LDLs. If the bad-guy LDLs hang around in your bloodstream too long they help form gunk in your arteries called plaques. If a piece of plaque breaks off, this can lead to a heart attack or stroke. This is where exercise can help. When you work up a sweat your body goes into garbage-removal mode and actually carries some of the bad cholesterol out before it has a chance to wreak havoc.

Better snugglin' with your honey – OK, so most of us would like to keep having sex as the years go by. And one of the best ways to ensure that your love life stays in synch is to get your blood moving through exercise. Experts say regular cardiovascular exercise, such as walking, running, or other aerobic fitness of your choosing – three to five days a week for about 30 minutes - should do the trick. As we become fit, the heart muscle becomes more efficient at pumping blood throughout the body, and our blood vessels, which have a tendency to get stiff and brittle from lack of exercise, become more flexible. Exercise also helps keep those pesky LDLs from forming plaques, aiding blood flow. And better circulation means less chance of impotence or erectile dysfunction. But men aren't the only ones whose sex drive can suffer from lousy blood flow. Ladies, if the blood isn't getting to where it needs to go, well, you get the picture.

Better thinkin' noggin – Working up a sweat is one of the best ways to stay mentally sharp as we age. Brain cells called neurons need a lot of support to ensure that we continue to think clearly and remember things. And when you increase your heart rate through physical activity, more blood gets to the brain, bringing with it valuable brain food called glucose and oxygen. Studies in animals have also found that exercise stimulates the release of proteins (called nerve growth factors) that act like fertilizer keeping neurons healthy. Scientists are beginning to think this may be the case in humans as well. And another bit of good news, aerobic exercise two or three times a week cuts your chances of getting dementia later in life in half.

The other night when I was walking on the raised track at the local YMCA, I was ready to say the heck with it and head home. I was tired from a long week at work, not sleeping well because of my husband's cold and just plain bushed from worrying about the economy. But I kept going. I looked down at the basketball court under the track and watched as about a dozen 5-year-olds struggled to heave basketballs up toward the net. They shoved, grunted, stumbled and giggled, which got me laughing and thinking. Though those little guys were moving differently, they were running and chasing rebounds. I was simply putting one tired foot in front of the other. Yet we shared something very important. We were doing something good for our minds and bodies and, with luck, making our lives a little better.

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Get a behind-the-scenes look at the latest stories from CNN Chief Medical Correspondent, Dr. Sanjay Gupta, Senior Medical Correspondent Elizabeth Cohen and the CNN Medical Unit producers. They'll share news and views on health and medical trends - info that will help you take better care of yourself and the people you love.