WASHINGTON, DC (WUSA9) -- Gastroenterologist Hal Kaplan spent more than 40 years in his profession. In 2013, he decided to hang up his stethoscope.
"I managed to stay retired for six full weeks, but I wasn't any good at it," he says.
Dr. Kaplan decided to return to work to teach medical students.
He says, "It really isn't work. It's doing what I enjoy."
There's a significant number of people who plan to keep working in their retirement years. A 2012 AARP survey of future retirees found 31 percent of people who enjoy their work plan to stay, that's up from 21 percent in 2007.
"People are remaining at work because they like what they are doing. They want to make a contribution. They want to remain active both physically and mentally," says AARP Public Policy Institute's Sara Rix.
Money is the number one reason people work during retirement. Kaplan is fortunate he doesn't need to do it for money. And, he plans to stick with it for now.
"It kind of depends in part on whether my brain and my body continue to function as well as they are now," he says.
Dr. Kaplan wants to stay until 2017 when the students he's working with graduate.
According to the AARP survey, 72 percent of future retirees say they plan to keep working either full time or part time.