The stress response is built for sprints, not marathons

Sapolsky's foundational point is that the body's emergency stress machinery evolved to solve a specific, narrow problem: surviving an acute physical threat lasting minutes, like outrunning a predator. During that window, the body reasonably diverts resources away from long-term maintenance projects — digestion, immune surveillance, tissue repair, reproduction — toward immediate survival needs like muscle fuel and oxygen delivery.

This trade-off works perfectly for a zebra, because once the chase ends, the emergency passes and normal maintenance resumes within minutes. The system is designed to be temporary and self-limiting.

The trouble is that humans can trigger the identical hormonal cascade through thought alone — worrying about a presentation, a relationship, or a bill — and these psychological stressors often don't resolve in minutes; they can persist for weeks or years. The same biological machinery that saves a zebra's life becomes, under chronic activation, something closer to a slow liability. Takeaway: notice whether your stress response is answering an actual emergency or an ongoing worry it can't actually fix.