According to the physical condition. Strong body, flexible legs and feet, quick response, but riding is ok; On the contrary, it is better not to ride.

To tell the truth, I generally don't advocate old people riding bicycles, especially those who are over 70 years old and sick. Even if it doesn't arrive.

70-year-old, 50-60-year-old people with prostate disease, it is best not to ride. This can't be generalized, but it varies from person to person.