Energy-based model explains how chronic stress transforms into disease over time

However moderate exercise (and stress!) stimulates the body to activate trash/repair/rebuild mechanisms which improve health overall.

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For example, aerobic exercise stimulates capillary growth lowering pressure required for blood flow. Periodic, moderate fasting triggers the elimination of accumulated fats which might have toxins built up in them (or have oxidized) Healthy, emotional stress teaches us to deal with inevitable tragedies.