Our bodies undergo a predictable transformation as we age, with less muscle and more fat, leaving us very different in our 50s and 60s than in our 20s. And while exercise can help mitigate the effects of aging, the best way to preserve our youthful values is to exercise more before the onset of middle age.
This does not mean discovering the joys of exercise later in life without benefits. Study after study has shown that regular exercise improves health, vigor and quality of life. But when it comes to strong muscles and bones, the best time to build both is over the years on both sides of puberty. Athletes who practiced sports before adolescence routinely demonstrated greater muscle and bone mass than those who started their athletic career later in life. The positive influence of exercise on body composition from infancy to adulthood is one of the reasons why health experts promote regular physical activity throughout life.
Adolescence marks the largest changes in fat and muscle composition, with fat-free mass doubling in girls and boys starting five years earlier and ending five years after reaching peak height. Obesity researchers now believe that the increase in fat-free mass that occurs during this 10-year period has a strong influence on body composition as an adult. Teenagers and young adults who get less fat free mass during those early years are at greater risk of fighting overweight as they get older.
Physical exercise is a vital component in adding muscles during the formative years, a magnitude of opportunity that is not matched later in life. Hence the importance of emphasizing regular physical activity from infancy to the mid-1920s.
Men lose an average of four pounds of muscle between the ages of 50 and 89 years, most of them in the lower body, a number that shows little change even among regular practitioners. Weight training can help mediate this loss, but the average amount of muscle gained by middle-aged adults dedicated to the gym is about one pound of lean body mass, which is modest compared to the amount of muscle that can be acquired during young adulthood.
Although an extra kilogram of muscle does not look like much, additional strength and endurance are instrumental in the ability to perform the tasks of everyday life. Exercise is a key component in delaying the mobility limitations we see in an older population. The more you exercise, the more vigorous you will remain as you walk the streets of your neighborhood, up and down stairs and doing household chores. So while a T-shirt is used to show a muscular physique in our youth, the ability to go up and down stairs and hurry up to the corner store is how we show our strength during the last years of life.
Adding to the change in body composition throughout the life cycle, it is from the mid-1920s that the fat has a trajectory opposite to the muscle. Boys experience a loss of fat and an increase in muscle in the years between adolescence and young adulthood, a process largely due to an increase in testosterone. In girls, however, body fat increases as they approach adulthood, with the end result being a 10 percent difference in body fat between men and women.
Once the specific gender distribution of fat and muscle takes shape, men and women consistently gain fat at similar rates. Again, exercise can help mitigate this increase, but even the most dedicated exerciser will see a drop in physical activity and muscle mass and fat gain as they get older.
Why do we need to know that the best opportunity to keep our weight under control is in our youth? With recent messages that exercise is not an important factor in taking away unwanted pounds in our adulthood, it is important to convey the message to parents, children and adolescents that exercise in childhood is critical to maintaining a healthy weight both immediately and after life . . Limiting unwanted fat gain, while increasing the amount of muscle during the first three decades of life, can make it easier to maintain pounds during the middle and succeeding decades.
It is also worth noting that overweight children and adolescents are less inclined to exercise than their thinner peers, which means it is never too early to get children to move. The bottom line is when it comes to maintaining a healthy weight, the role of exercise during those first few years can not be overstated. However, for older adults, exercise has less impact on body composition and more impact on health, mobility, energy, sleep, and quality of life.
Considering the value of being physically active throughout the life cycle, family fitness should be a priority. Active children become active adults with good health and vitality for the ride.