Senescence is the process of deterioration with age. While it remains a perpetual medical and scientific curiosity, the loss of power and growth is less about inquisitiveness to those of us having to endure its reality.
Aging is characterized by the declining ability to respond to stress, increased homeostatic imbalance, and increased risk of aging-associated diseases including cancer and heart disease. Aging has been defined as “a progressive deterioration of physiological function, an intrinsic age-related process of loss of viability and increase in vulnerability.”
Different speeds with which mortality increases with age correspond to different maximum life span among species. For example, a mouse is elderly at 3 years, a human is elderly at 80 years, and ginkgo trees show little effect of age even at 667 years.