When you think about it, sitting compresses the discs and vertebrae in your back. Whether you’re watching your television or your computer, you’re probably also straining your neck due to poor posture (per Total Chiropractic Care). Even though sitting on a couch might feel comfortable, certain muscles can become strained from this unnatural position. This puts your body out of its natural alignment and can result in back spasms, according to U.S. News and World Report.

While watching a television show or two won’t cause back pain, making a habit of spending too much time in front of the tube can weaken some of your muscles. Your legs might be exhausted after a long day, but sitting for a long time weakens the muscles of your legs and glutes. Weak legs and glutes can make you unstable when you stand up (per Better Health Channel). Sitting too long also shortens the psoas muscle, which connects your spine to your legs. When your psoas muscles are tight, you’ll feel more tension in your lower back when you stand up (per Greenwood Physical Therapy).