London: Solving the mystery behind circadian rhythms, researchers have found that the rod cells in our eyes set our so called internal clocks that regulate everything from our sleep-wake cycles to our appetites and hormone levels.It was known that light coming into our brains via our eyes set those clocks, but no one was sure exactly how this happens.
"One is that it had previously been thought that circadian rhythms could only be set at relatively bright light intensities, and that didn``t turn out to be the case," Nature quoted him as saying."And two, we knew going in that rods ``bleach,`` or become ineffective, when exposed to very bright light, so it was thought that rods couldn``t be involved in setting our clocks at all in intense light. But they are,” he added.In addition, the study has possible implications for older people being cared for in nursing homes and hospitals, he said."Older adults often lose their rod cells to age, which means that their caretakers would be well advised to regularly and deliberately expose them to bright natural daylight in order to make sure that their natural, biological rhythms remain in sync so their sleep-wake cycles remain accurately set," said Hattar."Otherwise, they could have sleep disturbances, such as intermittent waking or difficulty falling asleep, not to mention the impact on their appetite and other bodily functions,” he added.The study appeared in a recent issue of Nature Neuroscience. ANI