Physical activity: Muscle, bone health and mental well-being
Physical activity (part. 2)
Muscle and bone health Disorders and diseases affecting the muscles and bones, (such as osteoarthritis, low back pain and osteoporosis), can benefit from regular exercise.
Exercise training produces stronger muscles, tendons and ligaments and thicker, more dense bone.
Physical activity programmes designed to improve muscle strength have been reported to help older adults to maintain balance , which may result in a reduction in falls.
Exercise can also be effective in preventing low back pain and reduces reoccurrence of back problems. It is not clear, however, which type of exercise works best on back pain.
Physical activity has not been shown to help prevent osteoarthritis but walking programmes have been shown to help reduce pain, stiffness and disability and improve strength, mobility and overall ratings of life quality. Exercise training (involving weight bearing in addition to moderate to vigorous activity) can increase bone mineral density and bone size in adolescents, help maintain it in adults and slow decline in older age.
This can help to prevent or delay the onset of osteoporosis but cannot reverse osteoporosis once it has developed. Mental well-being Several well-designed studies have shown that physical activity can reduce clinical depression and can be as effective as traditional treatments such as psychotherapy.
Regular physical activity over several years may also reduce the risk of depression recurring. Physical activity has also been shown to improve psychological well being in people who are not suffering from mental disorders.
Hundreds of studies have documented improvements in subjective well being, mood and emotions, and self-perceptions such as body image, physical self-worth and self-esteem. Furthermore, both single bouts of activity and exercise training reduce anxiety and improve reaction to stress and the quality and length of sleep.
Exercise has also been shown to improve aspects of mental functioning such as planning, short-term memory and decision making. Physical activity appears to be particularly beneficial for older people by reducing the risk of dementia and Alzheimer disease. What are the costs of inactivity? The human body is designed for movement and a sedentary lifestyle has been linked to illness and premature death.
A review of 44 studies found that individuals, who maintain a reasonable amount of activity, particularly in their middle and later years of life, are twice as likely as their sedentary counterparts to avoid early death and serious illness.
This level of health benefit is similar to that gained by avoiding smoking and inactivity is now recognised as one of the risk factors for heart disease. How does this translate into economic costs? Although disease and early death cause suffering to victims and their friends and family, there are high economic costs in terms of sickness absence from work and health care.
Most of the studies have been conducted in the USA where it has been estimated that 18% of heart disease cases (at a cost of $24 billion -1995 $ value-) and 22% of colon cancer cases (at a cost of $2 billion) in the population may be caused by inactivity.
It is now known that the average medical costs for active people are 30% lower than those for inactive people. In Britain, where obesity rate is the highest in Europe (around 20% of the population, this being at least partially, a result of inactivity) the cost of obesity, has been estimated to be £500 million, causing 18 million days of sickness absence per year.
Bibliography * Andersen, L.B., Schnor, P., Schroll, M., & Hein, H.O. (2000). All-cause mortality associated with physical activity during leisure time, work, sports, and cycling to work. Archives of Internal Medicine, 160, 1621-1628.
* Biddle, S.J.H., Fox, K.R., & Boutcher, S.H. (2000). Physical activity and psychological well-being. London: Routledge.
* Bijnen, F.C., Feskens, E.J., Caspersen, C.J., Nagelkerke, N., Mosterd, W.L., & Kromhout, D. (1999). Baseline and previous physical activity in relation to mortality in elderly men: the Zutphen Elderly Study. American Journal of Epidemiology, 150, 1289-1296.
* Medicine and Science in Sports and Exercise (1999), Nov; 31 (11 Supplement).
* Blair, S.N. & Hardman, A. (1995). Special issue: Physical activity, health and well-being - an international scientific consensus conference. Research Quarterly for Exercise and Sport, 66 (4).
* Fogelholm, M., Kukkonen, M., & Harjula, K. (2000). Does physical activity prevent weight gain: A systematic review. Obesity Reviews, 1, 95-111.
* Lawlor, D. A., & Hopker, S. W. (2001). The effectiveness of exercise as an intervention in the management of depression: systematic review and meta-regression analysis of randomised controlled trials. British Medical Journal, 322, 1-8.
* Prentice, A.M., Jebb, S.A. (1995). Obesity in Britain: Gluttony or Sloth. British Medical Journal, 311, 437-439.
* Sports Council and Health Education Authority. (1992). Allied Dunbar National Fitness Survey. London: Sports Council/HEA.
* US Department of Health and Human Services (PHS). (1996). Physical activity and health. A report of the Surgeon General (Executive Summary). Pittsburgh, PA: Superintendent of Documents.