Parents are notorious for telling their children to "Sit up straight!" or "Don't slouch!" It turns out there are several good reasons to maintain good posture throughout your life. Posture affects your movements, your muscles, and even your organs. Slouching can affect the efficiency of your lungs to take in air. Bad posture can cause muscle tension, headaches, back aches, and inability of your body to adapt to different stresses.
The muscles that work together to keep us upright slowly build up as we grow. Babies have different posture than children, when our backs create the final curvature needed to oppose gravity. In order to maintain appropriate posture, make sure work environments are ergonomically correct and pay attention to how you sit and move around. Exercise is always important and helps strengthen muscles. Next time someone tells you to stand up tall, maybe it's time to improve your posture.