Thursday, March 26, 2009

Increased physical activity in middle age is followed by a reduction in mortality comparable with that associated with smoking cessation.

From British Medical Journal

Total Mortality After Changes in Leisure Time Physical Activity in 50 Year Old Men: 35 Year Follow-up of Population Based Cohort

Objective: To examine how change in level of physical activity after middle age influences mortality and to compare it with the effect of smoking cessation.
Design: Population based cohort study with follow-up over 35 years.
Setting: Municipality of Uppsala, Sweden.
Participants: 2205 men aged 50 in 1970-3 who were re-examined at ages 60, 70, 77, and 82 years.
Main Outcome Measure: Total (all cause) mortality.
Results: The absolute mortality rate was 27.1, 23.6, and 18.4 per 1000 person years in the groups with low, medium, and high physical activity, respectively. The relative rate reduction attributable to high physical activity was 32% for low and 22% for medium physical activity. Men who increased their physical activity level between the ages of 50 and 60 continued to have a higher mortality rate during the first five years of follow-up (adjusted hazard ratio 2.64, 95% confidence interval 1.32 to 5.27, compared with unchanged high physical activity). After 10 years of follow-up their increased physical activity was associated with reduced mortality to the level of men with unchanged high physical activity (1.10, 0.87 to 1.38). The reduction in mortality associated with increased physical activity (0.51, 0.26 to 0.97, compared with unchanged low physical activity) was similar to that associated with smoking cessation (0.64, 0.53 to 0.78, compared with continued smoking).
Conclusions: Increased physical activity in middle age is eventually followed by a reduction in mortality to the same level as seen among men with constantly high physical activity. This reduction is comparable with that associated with smoking cessation.

Physical inactivity is associated with increased incidence rates of obesity, diabetes, cardiovascular diseases, osteoporosis, and cancer. Short term randomised controlled trials in young to middle aged adults have shown a healthier risk profile with exercise. It is therefore recommended that adults engage in at least 30 minutes of moderate physical activity preferably on all days of the week. Adherence to these guidelines is associated with half the risk of mortality seen in sedentary people.

Principal findings of this study
Increased levels of physical activity in middle age have an effect on mortality. After a 10 year period of increased physical activity the excess mortality seen in inactive men was reduced to the same levels of mortality as seen in physically active men. There is, however, a period of at least 5 years before this risk reduction during which the risk is higher. The halved mortality rate after 10 years of follow-up after increased physical activity between the ages of 50 and 60 (compared with continued inactivity) was similar to that seen after smoking cessation (compared with continued smoking).

Full text article at BMJ

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