By becoming tough we preserve those physical and mental capacities that are degenerated by stress and by aging. The toughness model proposed in this book incorporates psychological research and neuroscience to explain how a variety of toughening activities - ranging from confronting mental and physical challenges to meditation and even giving and receiving nurturance - sustain our brains and bodies. These activities affect genetic processes that build neurochemical capacities and rebuild degraded brain structures. The physiological toughness leads, in turn, to improved mental/psychological...