The heart will like a slower life.
I remember the big one test, boys ran 1500 meters, because high school has rarely exercised, that run was particularly fierce, although the results were particularly good, but after the run they vomited and turned pale. At that time, both teachers and classmates were frightened.
At that time, I suddenly realized that it was really not so cool to compete for the first place and the record.
If you want to run fast and have good endurance, you must keep exercising every day and slowly get better, instead of suddenly running fast without any side effects.