Last week's article cited studies showing that intense exercise allowed 80-year-olds to retain even more muscle mass than those of the same age in good health and that the more overall movement you do past the age of 50 the better it is not only for your overall health but also for longevity.

In short - and in all honesty - exercise along with eating right is the closest thing to the fountain of youth (unless you're exceedingly wealthy and willing to drop a couple grand a month on growth hormone supplementation). But you should not wait until your golden years to drink from it. Aging is relative.You can be an old 28-, 18-, or eight-year-old. Particularly if you are out of shape or obese.During the American Heart Association's Scientific Sessions last year, Linyuan Jing Ph.D. presented a study that showed when compared to those subjects of normal weight, the obese subjects studied had 27 percent more muscle mass in the left ventricle of their hearts and 12 percent thicker heart muscles, two harbingers of heart disease. Additionally, the heart disease risk was further increased for 40 percent of the obese subjects because their thickened hearts were already pumping less blood.The especially sad and scary element to this study: Jing's study contained no adults, only children. Some as young as eight years old.Fifty years ago when the rate was one in nine, an overweight eight-year-old was not only a relative rarity but also a relatively mild concern. That's because back then most children shed what was affectionately called "baby fat" once the growth spurt that occurs with puberty increased the need for energy.That's no longer the case. Overweight pre- and post-pubescent children are commonplace and a serious concern.Today, the too frequent consumption of calorie-dense and nutritionally lacking food along with a comparative lack of exercise causes one in every three pre-pubescents to be overweight. Moreover, puberty is no longer the panacea.The rate of overweight post-pubescents is now the same as children - which is 300 percent higher than 50 years ago.A more recently released study of 2.3 million Israeli 17-year-olds weighed and measured for military service from 1967 to 2010 also found that increased weight early in life increases the risk of heart disease later.This research revealed that scoring above the 49th percentile as a 17-year-old on the body-mass index (BMI) clearly increased the eventual risk of death from heart disease and that those who scored over the 75th percentile not only increased the risk of death from heart disease, but also sudden death from unknown causes, death from all causes, and stroke. Those weighed and measured who scored between the 25th and 49th percentiles had the lowest rate of heart-disease death.Surprisingly, an increased rate of heart-disease death was also evident below the 5th percentile.But holding a seemingly healthy weight according to BMI as you progress into adulthood may not be enough if you strive for a lifetime of good health, according to a Swedish study released in March.In it, 1.5 million 18-year-old military recruits who had a normally healthy weight when BMI was calculated were tested for fitness. Those deemed to be in poor shape eventually developed type 2 diabetes at triple the rate of those found to be the fittest - even after the researchers eliminated the variables that could possibly affect the findings, such as family-health history and socio-economic status.The tests that scored muscle strength and aerobic capacity proved to be the most revealing. The authors of the study called poor performances in these areas "highly predictive" of developing type 2 diabetes in one's 50s and 60s.But youngsters should exercise for the immediate benefits as well as the future ones.A study published last year in the journal Pediatric Exercise revealed a correlation between a child's body weight and activity level and the ability to think. While prior studies had shown a link between fitness and increased cognition, this study showed that weight also plays a role.Researchers assessed 90 children between the ages of seven and 11, 45 of which were of normal weight and 45 of which were overweight. About half of the first group claimed to be physically active, a declaration that was then substantiated by corroboration. All other participants claimed to be physically inactive.That the active children had less body fat, a better BMI score, and a lower resting heart rate did not surprise the researchers. The disparity in cognitive scores, however, did.According to the Cognitive Assessment System, a frequently used and highly regarded test, the active normal weight children scored on the average eight percent better when compared to the inactive overweight children in the ability to pay attention. The active normal-weight kids also outscored the inactive overweight kids by nine percent when it came to figuring out and carrying out a strategy, as well as applying general knowledge.