I had the same problem and I solved it by taking some Magnesium chelate.
It is Magnesium bound to amino acids for easy assimilation and utilization. I do NOT recommend you take Magnesium Oxide. Magnesium citrate works but you will soon get a huge increase in your toliet paper bill if you take even a normal amount of this form.
I know Magnesium chelate works for other things also because when the ambulance took me to the hospital and parked me in front of the operating room while they did some required quick blood work, I heard my surgeon say "we will not need a magnesium drip for this guy" as he read the results. It helps stop arterial spasms which is not wanted when they operate on the heart.
jackD
It is rather cheap stuff.
http://www.vitaminshoppe.com/store/e...jsp?id=SR-2028