Summary and a Full Model: It’s a Tough Life

Abstract

Remember Isaac Newton’s third law of motion, mentioned in Chapter 1: “For every action, there is an equal and opposite reaction.” Now I reconsider and extend that idea, and thus re-engage opponent process theory to draw some conclusions about toughness. Perhaps the first law of toughness should read: For activities that use, tax, or deplete physiological systems in appropriately intermittent rhythms of challenge and recovery, there are opponent processes that will, over time, rebuild and restore those systems to even increased capacities; those toughened physiological systems shall, in turn, foster the mental/psychological aspects of toughness. Perhaps I should append a footnote explaining that for toughening to develop, depletion need not imply emptying physiological reservoirs. For toughening, sufficient depletion may follow from merely activating neural and endocrine systems, so that substantial amounts of consumable neurochemicals and energy are used.