You can die from pooping too hard. Source
True story. I used to be an EMT… This happens. And it ain’t pretty. Bearing down on the toilet can overstimulate your vagus nerve and cause you to faint. It’s called vasovagal syncope, and it drops your heart rate and blood pressure. Typically, blood flow would return to your brain and you’d regain consciousness. But…If you happen to also have cardiovascular or circulatory problems… it might not. That is why people sometimes die on the toilet.