We all understand what happens to our body as it ages. Without intervention (an exercise/activity program) we know that our muscles waste, our lung capacity decreases, our heart gets weaker, our bones become brittle, our flexibility and mobility decrease, our reaction time slows, our posture suffers, we move slower, and we become more susceptible to illness and injury.

Unless of course we happen to live a naturally active lifestyle (one where we regularly expend lots of energy, move, lift, stress our body — consistently do stuff physically).

I have written before about a concept called biological age (also known as physiological age) and we have established that by controlling certain variables (diet, lifestyle, exercise, stress levels) we can "turn back" our body clock. Even though we may be fifty (chronologically) we can 'build' ourself the body equivalent to that of a typical thirty year-old (in terms of cardio-vascular function, strength, bone density, blood pressure, and flexibility). If you've punished your body for fifty years it may be a different story, of course, but at the very least, you can turn back the clock a little and see a notable improvement in health, physical function and overall fitness.

What happens (typically) with a large percentage of the population is that we get to a point in time when we simply stop moving as much. We stop lifting, walking, hammering, climbing, cleaning, working — doing physical stuff. As soon as this happens, our body begins to age at a faster rate. The rate of aging is hard to quantify, as it varies from person to person, but let's just go with "a much greater rate."

For many people, retirement should be renamed the-beginning-of-the-end; they stop doing pretty much everything that kept them in shape. (I'm talking about from a health and function perspective here, not from a looking incredible perspective.)

I'm not suggesting that we all work until we're ninety five, but for some people, the day they retire is the day they stop using their mind and their body in a significant way. It is the day they begin to deteriorate. Ironic, when you consider how excited most people are about that day.

And while it's common and 'normal' for some of us to train our body in an effort to stay young physically, surprisingly, the majority of us don't consciously take a similar approach when it comes to keeping our mind in shape. We don't consciously 'exercise' our mind like we do our body.