Repeated conditions do not only shape what you think, expect, or do. They shape the body that is living through them.
If you repeatedly need to stay ready, readiness is not just an idea. Muscles prepare. Attention sharpens. Breathing changes. Rest becomes lighter. The body participates in meeting the conditions around it.
If this happens often enough, preparation can become familiar. Tension that once appeared in particular situations may become harder to distinguish from ordinary tension. A body that repeatedly had reason to remain alert may not fully settle simply because nothing is happening at the moment.
The same principle extends beyond vigilance. Repeated conditions can shape sleep, appetite, digestion, energy, movement, recovery, and the way effort is distributed through the body. What happens repeatedly becomes part of what the body has to organize around.
This does not mean that every physical problem begins with experience. Bodies are affected by illness, injury, nourishment, aging, environment, genetics, and countless other conditions. The point is simpler: experience is physical too.
A child waiting for an unpredictable adult is not having a psychological experience in one place and a bodily experience somewhere else. The watching, tightening, anticipating, thinking, feeling, and preparing are happening within one living system.
Over time, some of that organization can become ordinary enough to disappear from awareness. A person may know themselves as tense, restless, easily startled, tired, unable to settle, or always ready to move without experiencing any of those things as responses.
They may simply feel like the way their body is. And in an important sense, they are. The body has learned from the conditions it repeatedly lived through too.