A study from the National Institutes of Health found that those who sleep nine hours or more each night are almost twice as likely to develop Parkinson's disease as those who sleep six hours or less.
The More Sleep, the Greater the Risk
The health of 80,000 nurses, none of whom had Parkinson's disease at the beginning of the study, were tracked for 24 years. Analysis of the 181 women who developed Parkinson's during the course of the study showed that the longer they slept, the greater risk they had of developing the illness.
Nurses who slept at least nine hours a night were 80 percent more likely to receive a Parkinson's diagnosis, while eight hours elevated the risk by 60 percent and seven hours increased it by only 10 percent.
Working night shifts, however, reduced the risk. Longer stints offered more protection; nurses who worked overnight at least three times a month cut their Parkinson's risks in half. Previous studies have demonstrated that those who work night shifts have lower levels of the hormones melatonin and oestradiol, which may contribute to the development of Parkinson's at high levels.Symptoms of Parkinson's include tremors and muscle stiffness, and eventually speech, facial expression and balance can be affected.