My husband has constant cramps in his legs and toes, sometimes they wake him up from his sleep. he is 41 years old. ?

Lots of things: Lots of things can cause this, from potassium deficiency, iron deficiency, vascular problems, diabetes and idiopathic...Just to list a few..Please have your husband see his physician for full evaluation and blood work.

Additionally: Low magnesium, excessive alkalinity in the tissues of the muscles or in the nerves, excess sympathetic tone.