There are many reasons for feeling weak when piled up. You can't stand on an empty stomach or a full stomach. Staying piles should be done more than half an hour after meals, because a large amount of blood is supplied to the stomach after a short period of meals, and hasty practice is not conducive to digestion and is easy to be weak. Second, it is not advisable to stand on the pile half an hour before meals. The energy supply in the body is insufficient, and it is easy to be weak. It is difficult for blood to flow back to the digestive system after work. Fatigue caused by persistent mental stress. One is that after a long time, I always look forward to the time passing quickly, so I am nervous. The other is that people standing on the pile are always in a state of tension, and their brains are constantly excited and easily nervous at any time. If you can't relax mentally, can you stand on the pile without fatigue?