ABSTRACT
Gerontological research has made great strides in recent years in understanding how we age.1 Aging is a biological process that occurs at the molecular, cellular, and systems levels. These levels are both interdependent and independent. As molecules, cells, and systems change with age, the capacity of an organism to regulate itself declines. One of the hallmarks of the aging process is this decreased regulatory capacity in the face of external stressors.2 It ultimately leads to death. This research has provided new support for some theories of aging. Other theories now seem less useful or have been merged with others.
