Genetic research into aging is trying, in a way, to do just that. Several studies in the last two decades have pointed to hints about precisely what causes aging. If they get sufficient knowledge of the subject, there is some hope of altering the situation.

Until then, there are several things a sensible person can do to stay trim, flexible and within a healthy weight or body fat percentage range. At any age, diet and exercise are the twin partners required to achieve those goals.

For some, working out an hour per day every day – a five mile run, a long swim, hitting every station on the weight machine – is still feasible. Others will have to adjust their routine to what is realistic for their own circumstances. Don’t ignore the signals that will help guide you to do that. Mild discomfort is to be expected, especially the day after a vigorous workout. Extreme pain is a sign something is wrong.

There are dietary changes that will be needed, too.

As we age there’s a greater temptation to indulge in tasty, but high sugar, high fat foods. We see it as a reward for all the years of hard work and dietary discipline. Unfortunately, we pay a higher price later in life for those than we did in our 20s or 40s.

An occasional dessert is actually healthy, both for your state of mind and the sugar and fat. Both are essential compounds in moderation, though simple sugars are preferable to complex and unsaturated fats are preferable to saturated. Sugar is essential to generating the energy needed for all biological processes. ‘Good’ fats help regulate hormones, neural processes and other vital activities.

Staying active is equally as important as the proper diet. A good walk helps keep the cardiovascular system in working order. Mild stress on the muscles and joints keeps them lubricated and firm. Both muscle mass and bone density reduce dramatically in sedentary individuals.

Studies show that a sedentary 65 year old will have (on average) only 60% of the aerobic capacity of a 30 year old. Those who do no strength training lose muscle mass equivalent to seven pounds per decade. But those statistics are not written in stone. Exercise can help improve them tremendously.

Studies at various universities carried out for 25 years show that runners who continued to train kept almost all their capacity of 20 years previous. Those who engaged in resistance training maintained muscle mass equal to that of ten years earlier. Use it or lose it.

A person who has been idle, but suffers no debilitating disease, can reverse their odds. Start slow and think long term. Pain from overdoing it is one of the leading causes influencing people not to stick with it. Take long walks, then work up to more vigorous activities under the guidance of a professional.

Live a long and healthy life, not just a long one.

Exercising aids fitness in numerous ways, each involving one or more of those systems.

Increased physical activity causes the heart to work harder than at rest. That increases blood flow, floods tissues with fresh oxygen and removes cellular waste products.

Exercise causes the lungs to draw in extra oxygen to bathe the tissues and help power the heart. Exhalation removes carbon dioxide, a waste product of certain biochemical reactions.

Regular, moderate exercise helps raise HDL (High-Density Lipoprotein) cholesterol (the ‘good’ type). It helps regulate blood sugar levels and converts stored fat into sugars that are used to provide energy. That process also prevents obesity.

The other benefits of a regular fitness program are more obvious and usually among the more direct goals of most people who make the effort: increased muscle mass, toned legs, buttocks, arms, stomach and healthier looking skin. Along the way, the individual receives the added value of greater strength, improved balance, higher endurance and (often) a better frame of mind.

Different types of routines will emphasize one area more than another. Aerobic routines help the cardiovascular and pulmonary systems, weight lifting focuses on building muscle tone and mass, yoga and pilates helps balance, flexibility and muscular control. But each of these, and several more, help more than just the intended focus group. The body is an integrated system and improving one area almost always has beneficial consequences for others.

All those benefits, at least to a moderate degree, can be had for minimal daily effort. Moderate intensity activity for 30 minutes per day, at least five days per week, will go a long way toward optimizing fitness.

A brisk walk, taking the stairs up one or two flights, a short daily jog, jumping rope and many other simple activities can be carried out with no special equipment or training.

More intense activity, done properly, can raise that level even further. A vigorous tennis game, a few laps in the swimming pool, an hour on the treadmill or exercise bike, or any of a dozen others, can raise your fitness to a peak with only a moderate investment of time and money.

For the truly committed there are, of course, a thousand and one classes at the gym, and every conceivable kind of home fitness equipment to fit a variety of budgets. A daily routine using free weights, followed by a good jog around the park will keep all systems functioning well.

And, as Aristotle taught all those centuries ago, to function well is to live well.