Washington (CNN) Former President Jimmy Carter said if he were 80 years old he would not be able to handle the responsibilities of being President and joked that he hopes there is an "age limit" on the office.

The comments from the 94-year-old former commander-in-chief are especially notable as the age of the three top Democratic 2020 presidential hopefuls, who are in their 70s, has been the subject of ongoing debate. The 39th president didn't mention any Democratic candidates by name at a town hall at the Carter Center in Atlanta on Tuesday night when he was asked if he might consider running for a second, non-consecutive term.

"I hope there is an age limit," he said as the audience laughed. "You know, if I were just 80 years old, if I were 15 years younger, I don't believe I could undertake the duties that I experienced when I was President."

Carter said the presidency requires mental fortitude and one must "be able to adapt to new ideas."

"For one thing, you have to be very flexible with your mind. You have to be able to go from one subject to another on concentrate on each one adequately, and then put then all together in a comprehensive way like I did with Begin and Sadat with the peace agreement," Carter said, referring to a 1979 Egypt-Israel treaty that was signed by Egyptian President Anwar Sadat and Israeli Prime Minister Menachem Begin.

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