Running in the morning on an empty stomach is not good, for the young and fit people can still, can better consume fat, play a good effect of weight loss. However, it is very bad for poor health and the elderly, because running needs to consume a lot of energy, fasting can not provide the energy required for exercise, which can lead to hypoglycemia, and even fainting and falling. You can jog one hour after breakfast, and run fast only after two hours, otherwise it will cause nausea, vomiting and other bad digestive symptoms, and even gastrointestinal spasms and colic.