27 yr old slim male have sudden pain/cramp from my knee all the way to foot. these episodes happen only at night and only subside with heat. lost weig?

Nocturnal leg cramps: These are common and may be seen in a variety of situations. They can occur after a moderate or more exercise routine or the discontinuation of a routine. They can also occur when there are electrolyte imbalances. If not related to exercise changes, then seek primary care evaluation to rule out electrolytes and other causes.