This video, will address the many roles exercise can play in healthy and successful aging. In the previous videos of this module, I have discussed how exercise can lower the risk for obesity, heart disease, diabetes and cancer. As aging is a non-modifiable risk factor for all these conditions, it becomes even more imperative for older individuals to minimize as best they can, the modifiable risk factors for these diseases. As I have already discussed the role of regular physical activity in lowering those modifiable risk factors in the previous videos. I will now focus on several other factors that contribute to healthy aging and an improved quality of life. Individuals 65 years and older are the fastest growing segment of the population. As such, from a health care perspective alone it is important to take the proper steps to ensure a healthy lifestyle. Remaining sedentary actually contributes to many health problems previously attributed to being part of the aging process. While physiological aging is inevitable, functional declines in key variables such as stamina, strength, balance, and flexibility can be greatly offset by participation in a sound program of regular exercise. The benefits are many and significant including the ability to maintain an independent lifestyle and the high quality of life in the later years. Let's begin with cardiovascular endurance. Maximal oxygen consumption declines with advancing the age in sedentary males and females. This is the result of a reduction in both maximal cardiac output and arterial venous oxygen difference as per the peak equation discussed in the cardiovascular video. However, please notice that a lifetime of regular exercise results in approximately two fold increase in VO2max in adults 65 years and older when compared to their age match sedentary counterparts. Equally as important is the finding that it is never too late to begin an aerobic training program. Adults who initiate such a program when over the age of 65 years can reap the benefits of training with increases and VO2max and cardiovascular endurance. This will improve stamina for activities associated with daily living including gardening, shopping, golfing, tennis, and playing with grandchildren. A major health problem for older populations that is seldom mentioned in the media is that of Sarcopenia. Sarcopenia is defined as the loss of skeletal muscle mass at a function with advancing age. After the age of 50, sedentary men and women can lose up to 10 % of their muscle mass per decade. The functional consequences of this muscle loss are great. Not only is there the obvious loss in muscle strength but there is an associated decline in bone mineral density. The loss of strength also impairs one's ability to maintain balance during movement, thus, increasing the risk of falling. Along with brittle bones, falling is associated with the much greater risk of fractures in the elderly. Sarcopenia also negatively impacts VO2max and endurance. Taken together, these consequences of Sarcopenia can significantly reduce one's mobility and overall independence. Show in here is John at age 67 and 79. He is one of many who prove that muscle loss with age is more related to increasingly more sedentary lifestyle than due to the aging process itself. The ideal scenario would be one in which you are active when you are young and remained active throughout life. In this case muscle strength would be significantly greater at every age when compared to sedentary age matched individuals. However, as we become less active as we get older there is still a steady decline in muscle strength among all groups. As I've already stated it's never too late. Previously sedentary older adults who begin a strength training program late in life are capable of demonstrating similar training adaptations as their younger counterparts. As has already been described in module three. As shown here, 12 weeks of straight training in previously sedentary men in their late 60s significantly increased muscle mass and cross-sectional area of both legs. This increase in muscle mass was associated with equal improvements in strength. Remarkably, men and women in their 90s are still able to demonstrate training adaptations in muscle mass and strength. This added strength will allow these individuals in their ninth decade of life to stay mobile and independent, delaying the need for assisted living and confinement to a wheelchair. Now, let's examine the role of exercise for the prevention and treatment of osteoporosis. Osteoporosis is the result of a decrease in bone mineral density due to a calcium imbalance. It will result in frail and brittle bones that are easily fractured. It afflicts hundreds of millions of people worldwide-- 80 to 90% of whom are women. The risk factors for osteoporosis are many. Post-menopausal women are at the greatest risk. A family history of osteoporosis is the second non-modifiable risk factor. Among modifiable risk factors, physical inactivity, low calcium and vitamin D levels, along with smoking topped the list. Typical age related declines in bone mass and density are demonstrated here. Notice that post-menopausal women receiving estrogen replacement therapy can partially offset this decline as estrogen promotes calcium deposition into bone. Bone is similar to muscle and that when overloaded, it will adapt and strengthen. The mechanical stress placed upon the bone during repeated muscular contractions will stimulate calcium deposition into the bone and improve bone mineral density and strength. Physical inactivity will have the opposite effect. In fact, this is why astronauts exposed to prolong micro-gravity environment and space lose a significant amount of bone mass. As there is no gravity, normally weight bearing activities such as walking, place no mechanical stress or stimulus on bone. While running and cycling are good for improving bone density in the legs and spine, it is important to incorporate weightlifting component in your exercise routine particularly targeting the muscles and bones in your upper body as they receive little benefit from those aerobic activities. Here's one of many studies reporting the beneficial effects of regular exercise on bone health in populations that high risk for developing osteoporosis. Previously sedentary post-menopausal women demonstrated a 6% increase in lumbar bone mineral density following 17 months of aerobic exercise. While a 6% increase may not sound like much, it is a very significant improvement in such a short period of time in this vulnerable population. Also notice that after the training, bone density return to baseline as per the principle of reversibility. I will leave you with a more comprehensive list of the potential benefits of exercise for healthy aging. I will discuss the role of exercise in reducing the risk for age related dementia in the next video. In summary, many of the functional declines, once considered inevitable as part of the aging process are more likely attributable to a continued sedentary lifestyle. Regular physical activity can help maintain or improve endurance, strength, balance and bone density. These adaptations will contribute to one's mobility, independence and overall quality of life. Finally, it is never too late to reap the benefits from a program of regular exercise.
