If you spend a lot of time in your office chair (say, even more than in your bed), be sure it’s not damaging your body. “Ample lumbar support that adjusts as your lower back moves is the most important factor,” says Alan Hedge, a professor of ergonomics at Cornell University. The seat size should fit your frame, neither constricting nor so wide that using the armrests strains your shoulders. Your feet should be planted firmly on the ground to support proper spine position and prevent disk injury, and the seat shouldn’t restrict circulation in your legs by cutting into your knees, says Jerome F. McAndrews, a spokesman for the American Chiropractic Association. The arms should be at a height where your shoulders are not hiked up but, instead, “relaxed, as when you’re at rest,” says McAndrews. If you push down on the seat cushion and it doesn’t spring back, says Hedge, it can cause you to sit awkwardly―meaning you should go chair shopping.