This accelerometer study retells a familiar story, in that more active individuals have a lower rate of mortality in later life. In human studies it is challenging to move beyond simple correlation between these two pieces of data - is it that more robust people who were going to live longer anyway have a greater tendency to exercise, or is it that exercise produces benefits to health? The animal studies are quite definitive, however, in showing that exercise improves long term health and reduces incidence of age-related disease, even if it doesn't tend to increase overall life span in the same robust way that calorie restriction does.
Physical activity (PA) is an important determinant of health worldwide. It is estimated that inactivity causes 9% of premature mortality, approximately 5.3 million deaths a year. Although noncommunicable diseases (NCDs) that can be prevented by PA are associated with a higher proportion of deaths in high-income countries, high mortality rates due to these diseases are also observed in middle- or low-income countries, along with important mortality from communicable diseases.
Several studies have described an existing relationship between PA in older adults and the risk of all-causes mortality. These studies differ concerning PA assessment, length of follow-up, ethnicity, age at baseline, stratification variables, and other aspects, making comparison difficult. Newer literature with objectively measured PA using accelerometers suggests that increasing light physical activity (LPA) may also be important for reducing mortality in adults and older adults. This study aims to overcome some of the previous gaps in the scientific literature by evaluating the relationship between PA, measured by accelerometry and questionnaire, and risk of all-cause mortality in community-dwelling older adults from a Southern Brazilian city.
A representative sample of older adults (≥60 y) were enrolled in 2014. From the 1451 participants interviewed in 2014, 145 died (10%) after a follow-up of an average 2.6 years. Men and women in the highest tertile of overall PA had on average a 77% and 92% lower risk of mortality than their less active counterparts. The highest tertile of LPA was also related to a lower risk of mortality in individuals of both sexes (74% and 91% lower risk among men and women, respectively). Moderate to vigorous physical activity (MVPA) statistically reduced the risk of mortality only among women. Self-reported leisure-time PA was statistically associated with a lower risk of mortality only among men.