Very few people think of posture and muscle tone as being a function of brain activity. But it’s absolutely true. If a muscle is contracting, it’s because your nervous system is telling it to. To exemplify this let’s look at a few different situations of varying brain states:
The newborn state:
At this point only the very basic neurological structures to keep you alive have yet developed. You have not learned how to move or to resist gravity and your posture is fully flexed with your shoulders internally rotated and your hips externally rotated. This is the default state of your nervous system; the fetal position. Whenever your brain is functioning less than optimally this is the posture that you revert to.
As your brain ages and begins to degenerate your ability to resist gravity worsens. The saying goes “you are born in flexion, and you die in flexion”. It is in between these two stages that hopefully your brain is working well and you may stand fully upright.
However, life happens:
Anytime stress, both emotional and physical, increases to the point that it interferes with your ability to cope and overcome it, brain function is affected. You can’t think as clearly when you’re over-stressed. And it gets reflected in your muscle tone.
I realize she has to fit on top of her desk, but being bored is a sure way to destroy your posture. Picture the last time you were listening to a lecture that was extremely stimulating. The speaker was enthusiastic and energizing, you were on the edge of your seat. I promise you your posture was as upright as it ever was, without having to give it a single thought. Excitement and interest will activate your brain and will be reflected through your posture while boredom will do the opposite. The more personally rewarding your life is, and the more you enjoy what you do, the better your posture is. In the same vein (and not that I’m suggesting this) drugs that elevate arousal levels such as amphetamines, will also improve posture, while narcotics (drugs that induce sleepiness), will do the opposite.
Many people under appreciate how dynamic brain function is. It fluctuates constantly and can change appreciably over months and years. So take care of your brain! Stimulate it, feed it well, get good sleep and your posture will benefit. Brain function (like heart function), can either decline with age or it can improve with use and stimulation.
I should also mention that the converse is almost definitely true. If, through exercise, chiropractic, massage etc., your posture is improving over time, it is a very reasonable statement that your brain has benefited significantly. And improved brain function can be demonstrated by improved balance, coordination, muscle tone, eye movements, and other basic tests done during a physical exam. It is also very common for patients to report being able to think more clearly, feel less depressed, sleep better and other subjective reports of improved brain functioning in addition to the objective physical exam findings.