You’ve probably heard it before — sitting is the new smoking. But while smoking rates are declining, sedentary behaviors are only increasing. The average adult person spends more than half of his or her waking hours sitting, about 70%, according to research published in Mayo Clinic Proceedings. 

24/7 Tempo reviewed several medical sources, including National Health Institutes, to compile a list of at least 17 ways prolonged sitting can be bad for you. 

Even if you are meeting daily recommendations for sleep (about eight hours a day) and staying physically active (about an hour a day) there are still 15-16 hours a day when you could be active. You probably spent half of that time at work, which often involves sitting at a desk.

The problem is that, according to several studies, regardless of whether you’re exercising for about an hour a day, how you spend those 15-16 hours matters significantly. And if you spend them sitting, working out an hour or so a day may not be able to offset the damage you’re doing to your health. 

Most people know that sitting all day long is not a healthy habit, but many may not be aware of the dire consequences that may come with a sedentary lifestyle. Just like they may not be aware of certain “harmless” habits that are aging them much faster than they can imagine. 

While you may not be able to control your work environment, there are ways to minimize the damage even when your work involves sitting at a desk, including standing and stretching intermittently. And if you can avoid additional sitting at home (such as spending hours in front of the TV), you’re certainly ahead.

Click here to see the 17 ways in sitting too much is ruining your body.

To determine the ways in which uninterrupted sitting for long periods of time is causing damage to physical and mental health, 24/7 Tempo reviewed several sources, including the Centers for Disease Control and Prevention (CDC) and National Health Institutes as well as several medical schools.