Remaining seated too long can have a serious impact on your health. According to a report published by the U.S. National Library of Medicine, men who sit for too long may raise their risk of heart failure, even if they exercise regularly. In men who exercised, those who sat for five or more hours a day were 34 percent more likely to develop heart failure than those who sat for less than two hours. The American Heart Association suggests adults get at least 150 minutes of moderate exercise per week.