I just thought I would find out any effects Magnesium could have on sleep and I found this explanation. I thought it was particularly relevant to muscle spasms in PD:
How Magnesium helps in sleep.
* Among its many important qualities, magnesium has a calming effect on the nervous system. In fact, magnesium has recently received considerable attention as an inexpensive dietary supplement that can resolve and alleviate many sleep disturbances.
* Magnesium is considered the "anti-stress" mineral and is a natural tranquilizer. In the elderly, magnesium supplements were found to improve sleep by decreasing the release of cortisol, a known cause of sleep disruption. Stress depletes magnesium and magnesium relieves stress. When your magnesium levels are low, your nervous system gets out of balance, and you feel on edge, naturally resulting in tightening muscles.
* Although we expect sleep to relax us, when magnesium levels are low, it may not. When we sleep, muscle groups move and stretch, in preparation for the next days activity. However, magnesium works with the calcium in our bodies to help our muscles first contract and then relax again. Muscles contract with the help of stored calcium. Magnesium is the mineral that helps them relax. Without enough magnesium, muscles are unable to relax fully after contraction and nighttime muscle cramps develop, causing another sleep disruption.
* Studies suggest that magnesium deficiency may also be one of the causes of insomnia, a condition that is experienced by an estimated one out of two Americans. Magnesium eases anxiety, relaxes muscles and nerves resulting in an overall improvement of your nights sleep.
* Several studies show a lack of magnesium can alter electrical activity in the brain, causing agitated sleep and frequent awakenings. It appears that magnesium is important for a good night's sleep