Exercise can't be done on an empty stomach. It may be hunger, insufficient blood supply to the brain, or dizziness caused by hypoglycemia. Some people have low blood pressure, which may also be dizziness caused by cervical spondylosis. Generally speaking, the body is in a sub-health state and needs good health care or proper exercise. If you exercise first, be careful not to be too intense. In addition, it will be better to supplement nutrition properly and take some health care methods in time.