What was James Doolittle's personality traits?

He was a believer in physical fitness, and had an office in the Mutual of Omaha building in Los Angeles. The office was on the sixth floor. He would climb the stairs in the morning, walk downstairs for lunch, walk back up after lunch, and walk down again at the end of the business day. The building manager told me that he'd often see him on the stairways, but almost never in the elevator.