The link between circadian rhythms and aging
Human sleeping and waking patterns are largely governed by an internal circadian clock that corresponds closely with the 24-hour cycle of light and darkness. This circadian clock also controls other body functions, such as metabolism and temperature regulation.Studies in animals have found that when that rhythm gets thrown off, health problems including obesity and metabolic disorders such as diabetes can arise. Studies of people who work night shifts have also revealed an increased susceptibility to diabetes. A new study from MIT shows that a gene called SIRT1, previously shown to protect against diseases of aging, plays a key role in controlling these circadian rhythms. The researchers found that circadian function decays with aging in normal mice, and that boosting their SIRT1 levels in the brain could prevent this decay. Conversely, loss of SIRT1 function impairs circadian control in young mice, mimicking what happens in normal aging. Leonard Guarente is...