While previous studies have suggested that aging is affected by biological (circadian) clocks -- the internal mechanisms that coordinate daily changes in gene expression, physiological functions and behavior with external day/night cycles, some recent findings suggest that a disruption of the mammalian circadian clock results in accelerated aging and increased age-related diseases and disorders.  Natraj Krishnan, from Oregon State University (USA), and colleagues assessed whether disruption of the circadian clock affects lifespan and healthspan in a fruitfly model. Identifying how a key gene that helps control circadian rhythms can improve the health of aging fruit flies if it is intact, but can result in significant health impacts, up to and including earlier death, if it is absent, the researchers found that young fruit flies without this gene were able to handle some stress, but middle-aged and older flies were not. Finding that: “these data suggest that impaired stress defense pathways may contribute to accelerated aging,” the team concludes that: “we show that …  the circadian regulatory network becomes impaired with age.”