The aging process is of great interest to scientists and to all of us. The process is complex, a function of all higher animals. There is an internal "clock" that determines the length of life for all species. Not the exact length, but a range. In general, all animal groups die in about six times the interval between birth and maturity. In humans maturity is complete about aged 20. Thus the extremes of life may be near 120 years. Indeed there is one well documented person who lived to age 122. Sixty-five people in the world have good proof that they are 110 or more.
Some insight about aging comes from cultures of cell growth under "test tube" conditions. Young cells live much longer than old cells, in the same growth environment and with the same nutrition. The "clock" just runs down and stops. Same thing with animal cloning. The cloned animal is as old as the animal from which it was cloned, when born. Thus the clock has already been running. Cloning will not increase longevity.
Life expectancy has been steadily increasing in the past 100 years, not because the length of life is getting longer, but because good health habits and modern medicine are reducing the premature morbidity and mortality of modern existence. Avoiding smoking and excess alcohol, keeping a lean body weight, and exercising are clearly factors in increased longevity. So is the avoidance of life shortening diseases, mostly the infectious ones, such as tuberculosis, typhoid, and cholera in this country. Reducing traumatic deaths from accidents or warfare is another way to stop premature mortality.
Today the boy born in 2001 can expect to reach 74 on average. Girls will live to 80 if present predictions hold. How can you be sure to live to 100? An old joke I learned in medical school goes like this. "If you want to live to be 100, do not drink or smoke at all. Do not take any chances. Have sex only for pro creational purposes. Do not eat rich food, and do not travel unless you must. The fact is that you will not live to be 110, it will just SEEM like it!" This joke always gets a laugh.
Stress is also a factor in premature morbidity. How to avoid stress is difficult to do, particularly in a complex society. It is how you learn to handle stress that is more important than avoiding it. Also staying connected is important -- connections with spouses or other partners, family, friends, and church. Loners don't survive very well alone. Also the value of humor must be always remembered.
Keep smiling, loving and living is my advice for us all!
I'll be in touch next month!
Thomas Petty, MD