After the internal skill of martial arts reaches advanced level, people may die. Generally speaking, it will take more than ten years at the earliest to reach the advanced level, at least to the extent of external integration and internal mixing of Dan.

In modern times, there are very few people who can stand on the pillars to melt snow, and even fewer people can mix flowers and hold Dan, so it is not easy to practice internal work and die.

Health qigong, mainly based on raising, has never heard of the dead. But there are many kinds of deviance, but most of them are because of irregular breathing and too much mental stress, so they are not easy to die.

Summary: practicing internal strength won't kill anyone.