Why do my hands cramp up? i heard it was carpopedal spasms

Hyperventilation: Carpopedal spasms happen with low ionized calcium in the blood, usually when people hyperventilate from anxiety. These spasms are brief, and you also have tingling around the mouth and lightheadedness. If you don't seem to be hyperventilating, and the spasms are prolonged, carpal tunnel syndrome is common. There are rare neurological diseases as well.

Many causes: There are many potential causes ranging from metabolic, to electrolyte imbances, to neurologic, or musculoskeletal. Some causes may be systemic while others may be localized. Some may be peripheral whereas other will be central. There is no simple explanation. See your internist for a history and physical as well as basic studies.