According to The Huffington Post, the retiring pope has been making his travels to St. Peter's Basilica's altar on a moving platform. The 100-yard walk down the aisle has become too difficult.
He has reduced his travel outside the Vatican and limited his audiences. The outgoing Pope has admitted that age has diminished his mental and physical strength to lead the world's Roman Catholics.
His last visit to the USA was April 15, 2008 to April 20, 2008.
Despite having no known serious health problems, fatigue is understandable for a 85-year-old pope. A doctor acquainted with the pope's medical condition, spoke on condition of anonymity, that the pope is simply old and tired.
The Pontiff's problems with getting around, kneeling during prayer, and standing for long periods of time, were suspected as being due to painful osteoarthritis.
The stress accompanying the life of the Catholic Church's leader might have led to his decision to lead an easier life in retirement.