Did your mom ever tell you that?
(My mom didn't, but my grandmom would threaten me that a little bird was gonna come perch on my bottom lip if I kept sticking it out. Duly noted.)
I hate to tell ya, but there is something to that.
In the post about the 42 pound head, we can see how repeatedly keeping the head in the 'desktop' position creates adaptations in the supporting structures that help to maintain that position.
So, this is a good thing, right? I mean, look at the official definition of adaptation:
Adaptation: 1) adjustment to environmental conditions, such as modification of an organism or its parts that makes it more fit for existence under the conditions of its environment; 2) a heritable physical or behavioral trait that serves a specific function and improves an organism's fitness or survival.
But, consider this point (from biomechanist Katy Bowman's excellent book, Move Your DNA: Restore Your Health Through Natural Movement.):
"In a biological context, adaptation doesn't imply your body has been improved in the sense of having become healthier. Rather, adaptation is the result of your body's constant pursuit to conserve energy. Because we have practiced sitting daily, and for hours, our bodies have responded by making 'sitting' easier on us.
Tissues that spend most of their time in a fixed position will adapt to that position by making alterations that are fairly permanent. The changes are not truly permanent, as they can change over a long period of time with new habitual behavior, but your tissues don't change as much as you might assume - certainly not just because you get up out of a chair at the end of the day."
But, you have a standing desk. Or, you work out a few times a week, or even daily.
Swapping out one habitual static position for another (while the change itself is good) is now going to prompt the body to support THAT position more efficiently, which is really not what we're after.
As far as 'exercise' or working out, your body is adapting to what it's doing (and not doing) ALL the TIME. And, not just on a whole-body level, but on the cellular level.
Meaning, there is a difference between 'exercise' and 'movement' which we'll get into next time.
In the meantime, take this little "How Much Do You Sit" quiz, to get an idea your ratio between 'sitting' and 'non-sitting' time, or 'sitting' and 'time you could be moving', remembering that your body is adapting to what it's doing the most.