I am a healthy and reasonably fit 67-year-old female with a healthy diet, vegetables, fruits, protein, etc. All my exams show a clean bill of health. I am careful to maintain a good potassium balance by eating bananas. I work out gently about four times a week and do a lot of walking. I drink tonic water from time to time at my physician's suggestion. My leg cramps have stopped, but my right arm cramps come on suddenly nonetheless. Could this be a sign of something potentially dangerous? Could this herald the onset of a serious muscle disease?