Source: Article from Men’s Health Magazine

Do you sit all day at a desk? You’re courting muscle stiffness, poor balance and mobility, and lower-back, neck, and hip pain. But to understand why, you’ll need a quick primer on fascia, a tough connective tissue that covers all your muscles. While fascia is pliable, it tends to “set” in the position your muscles are in most often. So if you sit most of the time, your fascia adapts to that specific position.

Now think about where your hips and thighs are in relation to your torso while you’re sitting. They’re bent, which causes the muscles on the front of your thighs, known as hip flexors, to contract slightly, or shorten. The more you sit, the more the fascia will keep your hip flexors shortened. “If you’ve ever seen a guy walk with a forward lean, it’s often because of shortened hip flexors,” says Hartman. “The muscles don’t stretch as they naturally should. As a result, he’s not walking tall and straight because his fascia has adapted more to sitting than standing.”

This same effect can be seen in other areas of your body. For instance, if you spend a lot of time with your shoulders and upper back slumped over a keyboard, this eventually becomes your normal posture. “That’s not just an issue in terms of how you look; it frequently leads to chronic neck and shoulder pain,” says Hartman. Also, people who frequently cross their legs a certain way can experience hip imbalances. “This makes your entire lower body less stable, which decreases your agility and athletic performance and increases your risk for injuries,” Hartman says. Add all this up, and a person who sits a lot is less efficient not only at exercising, but also at simply moving from, say, the couch to the refrigerator.

There’s yet another problem with all that sitting. “If you spend too much time in a chair, your glute muscles will actually ‘forget’ how to fire,” says Hartman. This phenomenon is aptly nicknamed “gluteal amnesia.” A basic-anatomy reminder: Your glutes, or butt muscles, are your body’s largest muscle group. So if they aren’t functioning properly, you won’t be able to squat or deadlift as much weight, and you won’t burn as much fat. After all, muscles burn calories. And that makes your glutes a powerful furnace for fat—a furnace that’s probably been switched off if you spend most of the day on your duff.

It gets worse. Weak glutes as well as tight hip flexors cause your pelvis to tilt forward. This puts stress on your lumbar spine, resulting in lower-back pain. It also pushes your belly out, which gives you a protruding gut even if you don’t have an ounce of fat. “The changes to your muscles and posture from sitting are so small that you won’t notice them at first. But as you reach your 30s, 40s, 50s, and beyond, they’ll gradually become worse,” says Hartman, “and a lot harder to fix.”

So what’s a desk jockey to do? Hamilton’s advice: Think in terms of two spectrums of activity. One represents the activities you do that are considered regular exercise. But another denotes the amount of time you spend sitting versus the time you spend on your feet. “Then every day, make the small choices that will help move you in the right direction on that sitting-versus-standing spectrum,” says Hamilton.

Stand while you’re talking on the phone. It all adds up, and it all matters.

Of course, there’s a problem with all of this: It kills all our lame excuses for not exercising (no time for the gym, fungus on the shower-room floor, a rerun of The Office you haven’t seen). Now we have to redefine “workout” to include every waking moment of our days. But there’s a big payoff: more of those days to enjoy in the future. So get up off your chair and start non-exercising.