According to the Small Business Administration, more than five million Americans in that age bracket run their own businesses or are otherwise self-employed.
A government study also found that Americans 55 and older started 18.9 percent of all businesses created in 2008, compared with 10 percent in 2001.
Older adults are playing a large role in entrepreneurship partly because the number of Americans in that age category continue to increase.
But the study found that people tend to be at a stage of their lives where they want to pursue their long-held dreams.
For many, that dream is owning their own business.
For McGarity, it was one of the best decisions she has ever made.
She credits husband Jim for encouraging her to open the fitness center - something, she said, she wouldn't have imagined doing 10 years ago.
"He was always telling me to find my niche - something I could do that would be fulfilling," she said. "He saw my potential and kept offering encouragement."
After joining a local gym, McGarity said she began to see the benefits of opening her own fitness business.
"I thought it would be fun but it would also be a way to help women who wanted a place to exercise but in a more private, comfortable environment," she said.
Talking with the women who have joined Shape Up Shop, McGarity said she thinks she achieved that goal.
"I get a lot of positive feedback, which is very satisfying," she said.
But going into business, at any age, isn't for everyone, McGarity said.
"It depends on a lot of factors - health, financial situation, plus ambition and motivation," she said. "It takes a certain type of personality. And you have to work at it. You have to be willing to deal with the ups and downs. It's a lot of hard work."
McGarity said she always is looking for ways to improve the business. She went from offering the typical exercise equipment - treadmills, elliptical, bikes and weight equipment - to offering workshops, including yoga. The shop is adding Zumba, which McGarity said will be tailored to individuals "so everyone can go at their own pace." And in the fall, she'll offer hip-hop.
Doing research, McGarity said she decided against enrollment fees and doesn't hold people to yearly memberships. The shop also offers 24-hour access "with lots of surveillance and security so women always feel very safe."
McGarity said she has developed friendships with the women who come to her business - from all ages and all walks of life.
"It's become a social group," she said. "We get together once a month to talk about fitness, we celebrate birthdays, we help each other out with whatever problems we're facing."
"It's been a lot of fun," McGarity said. "I feel good about what I'm doing. I can't imagine not doing this."
A fresh start
Pam and Gerry Lute didn't plan on becoming innkeepers, especially not in their late 50s.
"It just sort of happened," Pam Lute said. "But I'm glad that it did."
The couple owns White Hall Manor Bed and Breakfast in Greencastle, Pa., an antebellum-style mansion on East Baltimore Street.
She originally is from Hagerstown, her husband is from Gordan, Pa., and together, they eventually settled in Mercersburg, Pa.
"But when our oldest son was killed in an accident, we wanted to move," Pam Lute said. "It took a toll on me. I couldn't pass the accident site."
So when the couple saw the big, white house in Greencastle and saw the for sale sign, "we knew we had to have it."
"We enjoy going to bed and breakfasts when we travel," she said. "So we thought, how hard would it be to run an inn?"
The Lutes sold their Mercersburg home and settled in to a new career.
But they also kept their old jobs.
Gerry Lute is employed full time with TruckCraft in Marion, Pa., while Pam Lute works part time at Miller-Bowersox Funeral Home.
But the couple doesn't seem to mind juggling jobs.
"We really like running a bed and breakfast," Pam Lute said. "I was a hairdresser for years, so I have the gift for gab. Plus, we get to meet so many fascinating people. All of our guests have been wonderful - people from England, Germany, Spain, Canada and all across the United States. We would never have met them, otherwise."
The couple recently both turned 60, she said, "and when we purchased the inn two years ago, we talked long and hard about the work that would be involved. But this was something we really wanted to do."
Her advice to other older entrepreneurs?
"You can't go into any business with a lot of debt," she said. "And you can't be afraid of hard work."
But, for the Lutes, it was the right choice.
"Our family and friends thought we were nuts," Pam Lute said. "And maybe we were. But we have that spirit of adventure. We love what we're doing."