14 May 2012:
Cooper and colleagues  have recently reported that cumulative leisure-time physical activity across adulthood may affect physical performance and strength in midlife. In all, 1189 men and 1253 women from the UK Medical Research Council National Survey of Health and Development, born in March 1946, participated in the study. Self-reported leisure-time physical activity at ages 36, 43 and 53 years was assessed and compared to grip strength, standing balance and chair rise times at age 53 years. It was found that more women than men were inactive at ages 36 and 43, whereas activity levels between genders at age 53 did not differ. However, men were stronger and had better physical performance at age 53 than women. Men appeared to have been of a higher educational level and occupational class. More women were never-smokers than men. Health status at age 53 between women and men did not differ. Independent positive effects of physical activity at all ages on chair rise performance and at ages 43 and 53 on standing balance performance were found, whereas physical activity at age 53 was associated only in men with grip strength. This study confirmed the cumulative benefits of physical activity in both men and women across adulthood for physical performance in midlife.
A low level of physical activity is a health burden, increasing the risk for obesity, cardiovascular disease, diabetes, osteoporosis and, most probably, sarcopenia. It is important to define physical activity and to quantify the amount that may attenuate age-related declines in physical performance. Physical activity is defined as any body movement that is produced by skeletal muscles that results in energy expenditure above the resting metabolic rate . Daily activities at light, moderate and vigorous intensities can positively affect physical performance and capability, whenever they are practiced for a minimum of 30 min, accumulated in sessions lasting at least 10 min . Physical capability refers to an individual's capacity to undertake the physical tasks of daily living. It can be assessed by grip strength, standing balance and chair rise, tests that reflect muscle strength, power, speed, mental concentration and subtle motor control .
Physical performance is dependent on muscle mass. Muscle mass and function are known to decline with age, the process named sarcopenia. Prevention of sarcopenia through daily, leisure-time physical activity could maintain physical performance and independence in midlife and old age. Few studies have objectively analyzed physical activity levels and sarcopenia. Pedometer-determined ambulatory activity has been associated with lower adiposity, decreased total body fat and trunk fat , and increase in skeletal muscle quality and function, especially leg strength . The physical activity level is a key determinant of physical capability and mobility in older men . It appears that general physical activity may be of benefit in the prevention of sarcopenia, particularly through maintenance of desirable body composition. The study by Cooper and colleagues has indirectly proven that physical activity across adulthood could prevent sarcopenia and that increased activity should be promoted early in adulthood to ensure physical capability later in life.
Teodora Beljic Zivkovic
Faculty of Medicine, University of Belgrade, 'Zvezdara' University Medical Center, Belgrade, Serbia
1. Cooper R, Mishra GD, Kuh D. Physical activity across adulthood and physical performance in midlife. Findings from a British birth cohort. Am J Prev Med 2011;41:376-84.
2. Caspersen CJ, Powel KE, Christenson GM. Physical activity, exercise and physical fitness: definitions and distinctions for health related research. Public Health Rep 1985;100:126-31.
3. Haskell WL, Lee IM, Pate RR, et al. Physical activity and public health: updated recommendation for adults from the American College of Sports Medicine and the American Heart Association. Circulation 2007;116:1081-93.
4. Motl RW, McAuley E. Physical activity, disability and quality of life in older adults. Phys Med Rehabil Clin N Am 2010;21:299-308.
5. Chan CB, Spangler E, Valcour J, Tudor-Locke CE. Cross-sectional relationship of pedometer-determined ambulatory activity to indicators of health. Obes Res 2003;11:1563-70.
6. Scott D, Blizzard L, Fell J, Jones G. Ambulatory activity, body composition and lower limb muscle strength in older adults. Med Sci Sports Exer 2009;904:383-9.
7. Morie M, Reid KF, Miciek R, et al. Habitual physical activity levels are associated with performance in measures of physical function and mobility in older men. J Am Geriatr Soc 2010;58:1727-33.