If a poison/toxin is given in a low dose,
it will then be inhibited when given in a high dose.
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Hormesis is one theory for why caloric restriction extends lifespan – it induces a chronic low level of stress is ultimately protective. People who calorically restrict have elevated levels of corticosteroids (stress hormone), which may then help build resistance to other life stressors.
Maybe this is another reason why the ashtanga yoga practice (or any regular exercise) is beneficial. By subjugating oneself to this daily stressor, perhaps it raises the stress threshold and builds “immunity” against much bigger life stressors (i.e. disease).