© ISTOCK.COM/YURI_ARCURSAging can be simply defined as changes over time in the biological functioning of an organism. These age-related changes are often responsible for the decline of immune, muscular, cognitive, and metabolic function, which ultimately leads to death of the organism. In humans, aging is also accompanied by the higher risk of diseases such as Alzheimer’s, cancer, and heart disease. These physiological signs of aging are difficult to measure, and current research on aging typically relies on mortality rates or measuring life span to assess the impacts of treatments, regimens, or genetic mutation on aging. However, these metrics do not adequately equate to the aging process and give little information regarding the health of the individuals or the population.
In the nematode Caenorhabditis elegans, for example, a model organism commonly used in aging research, alteration of single genes involved in any of four pathways (insulin signaling, dietary restriction, inhibition of translation, and the electron-transport-chain complex) can lead to significant life span extension. But do animals with such mutations stay healthy as they age, or is there a physiological cost to increased longevity? It is often assumed that an increase in life span will also lead to increased health span, but this has not been evaluated comprehensively.
Mortality rates and life span do not adequately equate to the aging process and give little information regarding the health of the individuals or the population.
In a recent study, we tried to answer this question by comparing ...
