A large volume of scientific evidence implicates physical inactivity as a major risk factor for non-communicable diseases and premature mortality. There is strong evidence that physical inactivity is associated with an increased risk of all-cause mortality, cardiovascular disease mortality, and several non-communicable diseases including coronary heart disease, stroke, hypertension, diabetes, dementia, depression, and cancers of the bladder, breast, colon, endometrium, esophagus, stomach, and kidney. However, more than a quarter of adults are not sufficiently active to achieve the associated health benefits. The public health burden associated with physical inactivity is a global issue that requires international collaboration to mobilize change.