It's tough growing older in a throw-away society where old age, experience and wisdom are less than revered. What is it that really causes us to age?

In Ageless Body, Timeless Mind, author Deepak Chopra, M.D. discusses the causes of and ways to override our natural tendency toward aging. A sedentary lifestyle is one culprit. Exercise can actually reverse the effects of entropy on muscle mass, strength, basal metabolic rate, body fat, aerobic capacity, blood pressure, blood-sugar tolerance, cholesterol/HDL ratio, bone density and body temperature regulation. Physical fitness and building muscle mass later in life not only affects us in those ways but also helps us feel younger and better about ourselves.

Keeping a balance between moderation (not going to extremes), regularity (a consistent routine, for the most part), rest and activity is key. Sleeping seven to eight hours a night, eating breakfast, not eating between meals, maintaining normal weight, regular physical activity, moderate drinking and not smoking have all been found to be contributors to longevity. A conclusion is that "a balanced lifestyle is one of the most important steps toward retarding the aging process."

Meanwhile, at the quantum level, we find that our thoughts about aging are perhaps even more important. A thought sends a message to the body; an emotion is transformed into molecules of enzymes or hormones in your bloodstream resulting in chemical and physical change.

Chopra says that "the body is a network of messages constantly being transmitted and received." Negative and false beliefs about the implications of aging create that reality. Positive, proactive behavior and belief that old age is valued and desirable creates a different reality.

Humans are the only animals who can change their physiology with intention. Experiments with placebos prove this. The pill is meaningless -- it's the power of suggestion that activates the placebo effect, which is then converted into the body's intention to cure itself. This leads to the conclusion that "the body is capable of producing any biochemical response once the mind has been given the appropriate suggestion." This would include intending not to age. He

"By inserting an intention into your thought processes, such as, 'I want to improve in energy and vigor every day,' " Chopra says, "you can begin to assert control over those brain centers that determine how much energy will be expressed in activity. The decline of vigor in old age is largely the result of people expecting to decline; they have unwittingly implanted a self-defeating intention in the form of a strong belief, and the mind-body connection automatically carries out this intention."