organic systems seek points of equilibrium, with veering too much off in any axis being detrimental
Hormesis is characterized by a biphasic dose-response: low-level exposures to stressors (toxins, temperature, exercise, dietary restriction, etc.) are those which stimulate adaptive beneficial responses, eg exercise, ischemic preconditioning (short bouts of reduced blood flow improving tissue resilience), and dietary energy restriction.
Rather than negating homeostasis, we can say that hormesis "refines" it: mild, intermittent stress can make us resilient through larger future perturbations.