The brain and body normalize elevated dopamine and norepinephrine levels through homeostatic plasticity, strengthening neural connections and reducing the critical requirement for such high increases.

“but there are systems in the brain and body that regulate the connections between neurons so that if dopamine and norepinephrine are elevated above Baseline levels for a while the system normalizes so that instead the connections between neurons become stronger and there isn't the critical requirement for all that increase in dopamine and norepinephrine”