Background
Physical inactivity is a common behavior in affluent societies and increases the risk for several non-communicable diseases. These diseases have a heavy burden in terms of healthy life years lost by the patients affected and lead to important social costs in two dimensions: the direct medical costs due to treatment of the diseases and the productivity losses due to absenteeism, disability and premature death. Direct medical costs and productivity losses due to physical inactivity in Switzerland had been estimated for 2001. More recent data has not been available yet.

Objectives
To estimate direct medical costs and productivity losses due to physical inactivity in Switzerland in 2011.

Methods
In this study, a person is considered as physically inactive, if she does not meet the following recommendations for health enhancing physical activity: at least 2.5 hours of physical activity with moderate intensity per week or 1.25 hours of sports with high intensity per week. Prevalence of physical inactivity is estimated based on the Swiss Health Survey. Risk ratios of diseases are extracted from literature. Population attributable fractions (PAFs) are calculated based on the prevalence of physical inactivity and the risk ratios. PAFs are then applied to the disease costs in order to estimate the direct medical costs and productivity losses due to physical inactivity. The disease costs stem from a recent study on the costs of non-communicable diseases in Switzerland.

Results
Based on the Swiss Health Survey 27.5% of the population over the age of 15 is physically inactive. The direct medical costs due to physical inactivity are estimated at CHF 1.165 billion or at 1.8% of total health care expenditures. 29% of these direct medical costs are due to cardiovascular diseases (ischemic heart disease, stroke and hypertension), 28% due to low back pain, 26% due to depression and the remaining 16% due to osteoporosis, diabetes type 2, obesity, colon cancer and breast cancer. Productivity losses are estimated at CHF 1.368 billion and are mainly caused by back pain (47%), depression (28%) and cardiovascular diseases (14%).

Conclusions
These results show the heavy impact of physical inactivity on the Swiss health care system and the society as a whole. Low back pain and depression, two diseases often not included in cost studies related to physical inactivity, significantly contribute to direct medical costs and productivity losses.

Implications
Interventions to reduce physical inactivity are indicated. Future research should investigate the effectiveness and the cost-effectiveness of such interventions.