Normal aging and human physiology

This article discusses the physiological changes that accompany normal aging and current understandings of how environmental factors interact with a person's genetic mechanisms to slow or speed up the aging process. Chronological age is contrasted with biological age to illustrate the different rates and extent of anatomical changes and functional declines observed in older people of the same age, behaviors that appear to delay or reduce the inevitable progression of sensescence, the extraordinary heterogeneity of the aging population, and the complexity of the processes responsible for the consequences of human aging.