Chronic lack of sleep and irregular sleep-wake cycles that disturb the biological cycle are likely to risk the onset of Parkinson's disease as well as worsen the disease warns a new study. The animals-based study showed that the disturbances in the circadian rhythm -- the roughly 24-hour biological cycle of humans daily exposure to long periods of light with brief exposure to dark may also dramatically worsen the motor and learning deficits brought on by the disease. Many think that sleep disturbances are secondary to Parkinson's disease. But circadian rhythm disturbances are increasingly reported before the onset of Parkinson's suggesting
