In an interview with the Atlantic online, Studs Terkel, the Pulitzer-prize author of more than 13 books said he isn't considering slowing down. Having published Will the Circle Be Unbroken at age 89, Terkel casually remarked, "I'm working on a couple of books now. I may not finish them โ€” the odds are I won't finish them โ€” but I like the journey as much as the destination."

We all want to go out like Studs Terkel โ€” relatively healthy and full of vigor, though indulging in two-martinis and a few cigars daily as he does may not be for all of us! Whether a Terkel-type fate awaits us depends on our environment, our lifestyle choices and the genes we inherit. But increasingly, we are learning that how we age is up to us.

In the landmark study "Successful Aging," sponsored by the John D. and Catherine T. MacArthur Foundation, researchers found that our genes determine 30 percent of aging; the remaining 70 percent is lifestyle driven.

Moreover, stunning advances in biomedicine such as the use of artificial organs portend that we may all be celebrating 100-year birthdays, maintains Ronald Klatz, M.D., president of the Academy of Anti-Aging Medicine. "Each of us today has a real chance to live, and live very well to age 100 and beyond," says Klatz, who acknowledges that his point of view has yet to be accepted by the mainstream medical community.

One-hundred-years old? Perhaps. 80? Quite likely if you're a women, reports the Centers for Disease Control and Prevention. (How much do you know about aging? Take our Aging IQ test.)

Why We Age

Okay. So let's say you have a 37.5-year-old body locked inside a 45 year old. Great! But you're still aging. Why? There are many theories of aging, but among the most widely accepted are the following three:

  • The Genetic Theory. We all have a "genetic timeclock" set to go off, though scientists aren't sure on the exact timing and what accounts for variations among us. We know, for instance, that the children of long-lived parents also tend to live long lives, and women worldwide outlive men. On the other hand, genes can hasten our demise. Recently, National Institutes of Health researchers identified a gene on chromosome number 10 that may account for the late onset of Alzheimer's disease, a condition that robs 4 million elderly Americans of their memory and independence and is expected to affect 15 million by 2030.
  • The Free Radical Theory. Free radicals, which are byproducts of everyday chemical reactions in the body, are usually disarmed by antioxidants (like Vitamins E and C) before they can do irreparable harm to our cells. But as we age, our body's ability to make the enzymes that produce antioxidants diminishes, explains Jeffrey Blumberg, a professor of nutrition at Tufts University and chief of the Antioxidants Research Laboratory at the Jean Mayer USDA Human Nutrition Research Center on Aging. Our diet, also a key source of antioxidants, deteriorates with age. Seniors are notoriously poor eaters. The upshot is that free radicals begin to run amok. To date, they have been implicated in more than 20 age-related diseases, including cancer, heart disease, macular degeneration and Parkinson's. To add insult to injury, free radicals also attack collagen and elastin, the substances of connective tissue that keep our skin moist and elastic. Loss of elasticity and tone results in thinner, sagging skin and wrinkles.
  • The Hormonal Theory. Menopause, andropause, osteoporosis, cardiovascular disease. The onset of these conditions is partially triggered by the reduction of hormone production that begins in our '30s and accelerates, as we grow older. Hormones such as estrogen, progesterone, testosterone, and human growth hormone, to name a few, also help us maintain vitality, libido, and "a joy for life," says Richard LeConde, an emergency room physician who now practices anti-aging medicine in Houston. LeConde and his colleagues maintain that restoring hormone levels in 40- to 60-year-olds to the levels typically found in healthy 25- to 35-year-olds is key to preventing some of the most deleterious manifestations of aging.