The cycle of life
While exercise is beneficial at any age, sweating early on pays off as you grow old
Our bodies go through a predictable transformation as we age, with less muscle and more fat, leaving us looking 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 figures is to exercise more before the onset of middle age.
That doesn’t mean discovering the joys of exercise later in life is without benefit. Study after study has shown that regular exercise improves health, vigour and quality of life. But when it comes to strong muscles and bones, the best time to build both is during the years on either side of puberty. Athletes who took up sports before adolescence have routinely demonstrated greater muscle and bone mass than those who began their athletic career later in life. The positive influence of exercise on body composition from childhood to adulthood is the one of the reasons health experts promote regular physical activity throughout life.
The teen years mark the biggest changes in fat and muscle composition, with fat-free mass doubling in both girls and boys starting five years before and ending five years after they reach maximum height. Obesity researchers now believe that the increase in fat-free mass that occurs during this 10-year span has a strong influence on body composition as an adult. Adolescents and young adults who put on less fat-free mass during those early years have a higher risk of battling excess weight as they age.
Exercise is a vital component in adding muscle during the formative years, a magnitude of opportunity that isn’t matched later in life. Hence the importance of stressing regular physical activity starting in childhood through the mid-20s.
Men lose an average of four kilograms of muscle between the ages of 50 and 89, much of it in the lower body, a number that shows little change even among regular exercisers. Weight training can help mediate that loss, but the average amount of muscle gained by middle-aged adults devoted to the gym is about one kilogram of lean body mass, which is modest compared to the amount of muscle that can be gained during young adulthood.
While an extra kilogram of muscle doesn’t seem like much, the added strength and endurance is instrumental in the ability to perform the tasks of everyday life. Exercise is a key component in delaying the limitations in mobility that we see in an older population. The more you exercise, the more spry you’ll remain while walking the streets of your neighbourhood, going up and down stairs and doing household tasks. So while a T-shirt is used to show off a muscular physique in our youth, the ability to hustle up and down stairs and walk briskly to the corner store is how we show off our strength during those later years of life.
Adding to the change in body composition over the life cycle is that, starting in the mid-20s, fat has an opposite trajectory to 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 about a 10 per cent difference in body fat between men and women.
Once the gender specific distribution of fat and muscle takes shape, men and women steadily gain fat at similar rates. Again, exercise can help mitigate that increase, but even the most dedicated exerciser will see a drop in physical activity and muscle mass and a gain in fat as they age.
Why do we need to know that the best opportunity to keep our weight in check is in our youth? With recent messages that exercise isn’t a major factor in taking off unwanted pounds in our adult years, it’s important to pass along the message to parents, kids and teens that childhood exercise is instrumental in maintaining a healthy weight both immediately and later in life. Limiting the gain of unwanted fat while boosting the amount of muscle during the first three decades of life can make it easier to keep the pounds off during the middle decades and beyond.
Also worth noting is that overweight children and teens are less inclined to exercise than their skinnier peers, which means it’s never too early to get kids moving. The bottom line is when it comes to maintaining a healthy weight, the role of exercise during those early years can’t be overstated. Meanwhile, for older adults exercise has less of an impact on body composition and more of an 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 kids become active adults, with good health and vitality going along for the ride.