There're number of articles that suggest sedentary lifestyle is dangerous for health some of which go as far as saying it's as bad as smoking.
According to an article on John Hopkins Medicine:
Lack of physical activity has clearly been shown to be a risk factor for cardiovascular disease and other conditions:
Less active and less fit people have a greater risk of developing high blood pressure.
Physical activity can reduce your risk for type 2 diabetes.
Studies show that physically active people are less likely to develop coronary heart disease than those who are inactive. This is even after researchers accounted for smoking, alcohol use, and diet.
Lack of physical activity can add to feelings of anxiety and depression.
Physical inactivity may increase the risk of certain cancers.
But many studies I've encountered are just observational studies that show correlation for low physical activities like watching TV.
Are there any studies that directly establish causal link between these conditions and sedentary lifestyle? (And not, for example, simply having obesity as a confounding factor?)