Many healthy behaviors help prevent the deterioration of aging, as explained in the book, Improve Your for a Healthy Brain. Memory Is the Canary in Your Brain's Coal Mine. One of the most important healthy behaviors is exercise. If you haven't taken up a regular exercise program, it is past time to start.

Have you noticed that many elderly people seem frail, walk slowly, and seem to lack energy? If this applies to you, noticing it is unavoidable. These problems are preventable. For 25 years, I jogged at least a mile and a half three times a week. This was crucial for helping me stop smoking. I don’t know why, except that I could not smoke and jog at the same time. Also, the 15 to 30 minute recovery time reminded me just how bad smoking had been for my health.

Why did I quit jogging? The jogging messed up my joints. So, I took up swimming, but since I sink like a lead mannequin, it was too much work. Now, I joined a gym, where I use the elliptical, treadmill, and muscle-building machines. This environment helps because I have companions in my discomfort, and occasionally I get the satisfaction of comparing myself to the few “90-pound weaklings” that show up.

We have known for many years that exercise is good for you, especially as you get older. Known benefits of exercise include:

Relieve and promote a sense of well-being. (Well, at least after the soreness wears off).

Improve heart and cardiovascular function. (If the damage is already done, don’t expect huge improvements).

Lose weight. (Pushing away from the table is the best exercise for this effect).

Strengthens bones. (Reduces loss of bone density in old age. But high-impact exercise may damage joints).

Lower blood sugar and help insulin work better.

Help . (Ever try to smoke while jogging?)

Improve mood and resist . (Ever heard of “runner’s high? It comes from a release of endogenous ).

Releases proteins and other chemicals that improve the structure and function of your brain. (Memory ability improves too).

Improve your sleep. (I mean, besides making you really tired. To reduce interference from soreness, take acetaminophen before bedtime).

Reduce the risk of some cancers, including colon, breast, uterine, and lung cancer.

What was not as well known until recently was the effect of exercise on the immune system. Recent research indicates that exercise in older age can prevent the immune system from declining and protect people against infections. A recent study followed 125 long-distance cyclists and found that some of those in their 80s had the immune systems of 20-year olds. Maybe this is a reason exercise can help prevent cancer.

The key indicator was the level of T-cells in the blood. T-cells, named after the thymus where they first appear, are a type of white blood cell that makes antibodies. As people age, the thymus gland, located in the neck, shrinks and T-cell activity resides mostly in bone marrow. The study of cyclists revealed that they were producing the same level of T-cells as 20-year olds, whereas a comparison group of inactive older adults was producing very few. Thus, it would seem that, though not tested in this study, physically active seniors would also respond better to vaccines than sedentary people.

The other new discovery is the importance of exercise on brain white matter integrity. White matter electrically insulates nerve fibers, which has two effects. It speeds communication in networks, and it reduces “cross-talk” among adjacent fibers. The study compared people averaging 65 with no cognitive impairment and those with , which is a risk factor for developing Alzheimer’s disease. In both groups, investigators measured cardiovascular function with a standard measure of heart and respiratory fitness, the VO2 Max test. They also used brain scans to measure white matter integrity. Levels of physical activity were positively associated with white matter (WM) integrity and cognitive performance in normal adults and even in patients with mild cognitive impairment.

Given the new research, how much more reason do you need to get off the couch and start moving? Besides, at the end of a good workout, it feels so good to quit.