1, due to the poor strength of abdominal muscles, the cervical spine and surrounding muscles exert too much force when doing sit-ups, resulting in temporary nerve compression and temporary dizziness and nausea.

2, girls usually do not eat well, have hypoglycemia symptoms, do sit-ups, especially girls who do not often, there will be insufficient blood supply to the brain, temporary hypoxia, dizziness, nausea.

3, just finished eating, the food is still stored in the stomach, undigested, causing nausea.

Solution: do strenuous exercise for at least 40 minutes after meals; Not picky about food, not dieting to lose weight; Exercise should be gradual, and you must not suddenly think of it. You know, you can't eat a fat man in one bite. Take your time and stick to it!