Why do my abdominal muscles cramp intensely when I sit straight up in bed?
1. Introduction Abdominal muscles cramp intensely when sitting straight up in bed due to a sudden, forceful contraction of the rectus abdominis from an elongated, resting state. This abrupt mechanical load, often combined with underlying physiological factors such as nocturnal dehydration, minor electrolyte imbalances, or localized muscular fatigue, causes the muscle fibers to misfire and … Read more