Updated 1.45pm
Pope Francis has warned that he must slow down his rate of travel or consider resigning, as knee pain and old age complicate his work schedule.
"I don't think I can go at the same pace as I used to travel," Francis, 85, told reporters on the papal plane as he left Canada.
"I think that at my age and with this (knee) limitation, I have to save myself a little bit to be able to serve the Church. Or, alternatively, to think about the possibility of stepping aside."
It was not the first time Francis has said that -- should his health require it -- he could take a page from his predecessor Benedict XVI, who made history in 2013 by stepping down due to declining physical and mental health.
In 2014, a year into his papacy, Francis told reporters that if his health got in the way of his functions as pope, he would consider stepping down.
In May, as reported in the Italian media, Francis joked about his knee during a closed-door meeting with bishops, saying: "Rather than operate, I'll resign."
"The door is open, it's one of the normal options, but up until now I haven't knocked on this door," he said Saturday.
"But that doesn't mean the day after tomorrow I don't start...
