I have never heard of CFS. I have had cramping for approximately 2 months now. The cramps occurred only in the mornings when I woke up and did a little body stretch in bed, calves and feet cramps. Now I get cramps throughout the night and (not getting good sleep) and during the day. The cramps have escalated to the calves, feet, shins, ankles hamstrings and hands. The hand and hamstring cramps have only occurred during the day. Been taking potassium, magnesium glynicate, drinking electrolytes, and eating bananas every day. Nothing seems to help.