We all know that slouching in chairs and sitting in cars all day is no good for our bodies. But can even a little laziness—a few days off from the gym, a weekend of lounging—cause problems? It appears so: A new study suggests healthy people will develop higher blood sugar after only three days of a sedentary lifestyle.
Most studies that just compare sedentary people with active ones don’t tell us much about whether sedentary living actually causes the problems—diabetes, high blood pressure, and so on—associated with it. The inactive people with health problems might have genetic or other reasons for them, and it could be that their illnesses are causing their lack of exercise, rather than the other way around. But this study is pretty clever: it compares people against themselves before and after forced laziness, so differences can be pinned to reduced activity.