1, because the accelerated metabolism opens up your tiny blood vessels, and fresh blood will itch when it enters. Mainly due to exercise, heat, mental stress, eating hot drinks or alcoholic drinks, the deep body temperature rises, prompting acetylcholine to act on mast cells and itch.

2. It may be skin itching caused by rubbing skin on the stomach during exercise, or skin allergy caused by contact with fitness equipment. It is recommended to stop exercising first.