You can try whether there is the same situation during low-intensity exercise, and whether it is different to eat less on an empty stomach. Generally speaking, there are more nervous stomach cramps, mainly because the nervous system is not adapted to the protective reaction caused by such high load of exercise intensity, and the reaction intensity and state of different people are different. If this is the case, in addition to strengthening low-intensity aerobic exercise to improve basic endurance and maximum oxygen uptake (not vital capacity, vital capacity can not reflect exercise ability), it is necessary to do some warm-up activities before strenuous exercise.
Generally, medication is not required. If it is organic, that is, stomach ischemia caused by exercise leads to stomach adverse reactions, it will be more troublesome and generally requires drug treatment. But this situation should also appear in low-intensity but long-term aerobic exercise.