A gene previously shown to protect against diseases of aging, plays a key role in controlling circadian rhythms, or sleep cycles, U.S. researchers say. Senior author Leonard Guarente of the Massachusetts Institute of Technology said human sleeping/waking patterns are largely governed by an internal circadian clock that corresponds closely with the 24-hour cycle of light and darkness. Studies in animals found, when these rhythm gets thrown off, health problems including obesity and metabolic disorders such as diabetes can arise, Guarente said. The researchers found 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. Since the SIRT1 protein itself was found to decline with aging in the normal mice, the findings suggest drugs that enhance SIRT1 activity in humans could have widespread health benefits, Guarente said. \"If we could keep SIRT1 as active as possible as we get older, then we\'d be able to retard aging in the central clock in the brain, and health benefits would radiate from that,\" Guarente said in a statement. The findings were published in the journal Cell.