It’s something that develops with time. We usually say it’s because you slump in front of a computer all day. Or you’re always hunched over at your desk. Essentially, we devolve based on our habits.
Here’s a different take on it: Since you probably know by now that I think that high blood pressure starts in the brain, people start to slouch when they get older [typically]. When you get older, you start to worry about dying. And when you start to worry about dying, you cling to the best metric we have to determine longevity: blood pressure. So you do whatever you can, take whatever the doctor prescribes to get that number as low as possible. And guess what: it works. Your blood pressure is just as good as a seventeen-year-old boy.
One problem, in your shotgun approach to lower your blood pressure, you cooled your brain off. With a cooler brain, time will fly by much faster, and you’ll have to press to keep up with your normal workload.
But how could you make the same amount of decisions in a day with a cooler brain? You restrict airflow. The brain has no choice but to heat back up. The slouch is a technique to increase stress and raise brain entropy. To make the same number of decisions each day with time moving so much faster, you must strain.
Cooling the brain off may increase lifespan, but it comes at a price. The slouch is the biological response to operate in increasing stress or to operate in the same stress with a cooler brain.