Your Tendency: To slump in your seat, be it on a plane or a train or in a car. But this can overstretch muscles in the upper back and cause the chest to cave in, which encourages shallow breathing. You may also sit for hours on end without taking a stretching break. But too much time in one position can increase the risk of blood clots by hampering circulation.

The Better Way: To sit with your legs uncrossed, your feet flat on the floor, and your spine straight. Place a small pillow behind your lower back to support it without exaggerating the natural curve. Sit on a folded blanket or a pillow to keep your knees slightly lower than your hips and relieve pressure on your lower back. At least once an hour, take a minute to get up and stretch.