Young men may be more vulnerable to becoming sedentary later on than women are if they are depressed at a young age, a study finds. It's not news that being a couch potato is bad for your health. Lack of physical activity is associated with a range of diseases from diabetes to heart attacks. Findings from this new study show that young men who have experienced depression early in life may be especially vulnerable to becoming sedentary later in life, and particularly to spending large amounts of time online each day.