Pacing is to walking as the treadmill is to the sidewalk. It is walking on adrenaline, super-charged with nervous energy that must be let out, even if there's nowhere to put it.
While I'm lucky enough to have a strip of asphalt on which to pound out my anxieties, there have been times when nothing made me feel better than walking the circuit through my house: living room, hall, office, kitchen ... living room, hall, office, kitchen.
I've never thought this a failing, only a useful habit. But reading A Gentleman in Moscow, by Amor Towles, has given me second thoughts:
...[I]t had been the Count's experience that men prone to pace are always on the verge of acting impulsively. For while the men who pace are being whipped along by logic, it is a multifaceted sort of logic, which brings them no closer to a clear understanding, or even a state of conviction. Rather it leaves them at such a loss that they end up exposed to the influence of the merest whim, to the seduction of the rash or reckless act—almost as if they had never considered the matter at all.
I'll never look at pacing the same way again.
(It's not pacing if you do it in a portico.)