Humans evolved in an environment of physical exertion, and our biochemistry requires physical exertion in order to trigger mechanisms of cell maintenance and metabolic regulation. Populations that exercise vigorously into late old age, such as the Tsimane in Bolivia, exhibit very much lower levels of cardiovascular disease. Further, living a sedentary lifestyle shortens life expectancy and increases disease risk when compared to people who exercise even the moderate amount that is the present recommended level. The dose-response curve data for physical activity suggests that the recommended level should be a good deal higher.
Physical inactivity is a risk factor for premature mortality and several non-communicable diseases. The purpose of this study was to estimate the global burden associated with physical inactivity, and to examine differences by country income and region. Population-level, prevalence-based population attributable risks (PAR) were calculated for 168 countries to estimate how much disease could be averted if physical inactivity were eliminated. We calculated PARs (percentage of cases attributable to inactivity) for all-cause mortality, cardiovascular disease mortality and non-communicable diseases including coronary heart disease, stroke, hypertension, type 2 diabetes, dementia, depression, and cancers.
Globally, 7.2% and 7.6% of all-cause and cardiovascular disease deaths, respectively, are attributable to physical inactivity. The proportions of non-communicable diseases attributable to physical inactivity range from 1.6% for hypertension to 8.1% for dementia. There was an increasing gradient across income groups; PARs were more than double in high-income compared with low-income countries. However, 69% of total deaths and 74% of cardiovascular disease deaths associated with physical inactivity are occurring in middle-income countries, given their population size. Regional differences were also observed, with the PARs occurring in Latin America/Caribbean and high-income Western and Asia-Pacific countries, and the lowest burden occurring in Oceania and East/Southeast Asia.