Poor posture distorts the alignment of your bones, chronically tenses your muscles, and contributes to stressful conditions such as loss of vital lung capacity, increased fatigue, reduced blood and oxygen to the brain, limited range of motion, stiffness of joints, pain syndromes, reduced mental alertness, and decreased productivity at work. According to the Nobel Laureate Dr. Roger Sperry, "the more mechanically distorted a person is, the less energy is available for thinking, metabolism, and healing."
The most immediate problem with poor posture is that it creates chronic muscle tension as the weight of the head and upper body must be supported by the muscles instead of the bones.
Think about carrying a briefcase. If you had to carry a briefcase with your arms outstretched in front of you, it would not take long before the muscles of your shoulders would be completely exhausted. This is because carrying the briefcase far away from your center of balance places undue stress on your shoulder muscles. If you held the same briefcase down at your side, your muscles would NOT fatigue as quickly, because the briefcase is closer to your center of balance and therefore the weight is supported by the bones of the skeleton, rather than the muscles.
In some parts of the world, women can carry big pots full of water from distant water sources back to their homes. They are able to carry these heavy pots a long distance without significant effort because they balance them on the top of their heads, thereby carrying them at their center of balance and allowing the strength of their skeleton to bear the weight, rather than their muscles.
Correcting bad posture and the physical problems that result can be accomplished in two ways. The first is by eliminating as much "bad" stress from your body as possible. Bad stress includes all the factors, habits, or stressors that cause your body to deviate from your structural center.
The second is by applying "good" stress on the body in an effort to move your posture back toward your center of balance. This can be accomplished through exercise, stretching, chiropractic adjustments, and changes to your physical environment, all designed to help correct your posture. Getting your body back to its center of balance by improving your posture is critically important to improving how you feel.