INSIDE the lower-level studio of the McBurney Y in the Chelsea neighborhood of Manhattan, Abba's 1970s hit "Dancing Queen" is thumping out: "See that girl, watch that scene, diggin' the dancing queen." Right in step to the bouncing beat is a senior squad of 40 slightly sweaty women and men, ages 60 to 85.
This Active Older Adults Power class is filled to capacity. The high-energy 59-year-old instructor, Roseann Brown, is not surprised. Attendance has doubled in these kinds of active adult exercise classes since she became a senior fitness instructor four years ago. Little wonder that the number of fitness clubs and gyms across the country offering these special classes is rapidly multiplying, according to fitness industry experts.
Ms. Brown has tapped into a budding field. As the population ages, jobs like senior fitness trainer and other jobs in health care, housing and other areas are on the rise. By 2050, according to Pew Research projections, about one in five Americans will be over 65, up from 13 percent of the United States population now. This demographic shift is already creating new fields and opportunities for workers of all ages.
"As tens of millions of people live into their 80s and 90s, we'll need millions of others in their 50s and 60s and 70s to help care for them -- not just within families, but through second careers," said Marc Freedman, author of "The Big Shift: Navigating the New Stage Beyond Midlife."
"They'll be able to fill millions of positions we will need to fill -- as nurses, home health aides, health navigators and roles we've yet to even define," he said.
Certain workers are already clearly in demand, including fitness coaches like Ms. Brown, people who modify homes to make them safer, certified financial planners and people who can offer monthly help with finances and bill-paying.
How do you exploit the emerging gray-jobs marketplace?
First, you probably need to bolster your résumé with new skills. But if heading back to school for a full degree program or a master's seems too expensive and time-consuming, there are less expensive and faster certificate programs that could fit the bill. In recent years, they have been proliferating at community colleges and universities across the country. And employers and clients are increasingly accepting professional certifications as proof of one's expertise.
Here is a sampler of growing job sectors serving an aging population and the continuing education you may need for a job:
Home Modification Pro
A recent report from Harvard's Joint Center for Housing Studies predicts a continued period of recovery and growth for the American home improvement industry, powered in large part by the many older homeowners who are preparing to age in place.
So the industry is likely to look different from just a few years ago. Rather than building an addition to a home or refinishing a basement, jobs are likely to involve remodeling to make homes easier for older adults to live in after retirement. "It's a concept whose time has come," says Esther Greenhouse, an independent consultant on elder- and disability-friendly design and policy based in Ithaca, N.Y.
Pay can start at $40 an hour, but experts like Ms. Greenhouse, 42, who teaches courses on aging in place for the National Association of Home Builders and consults for major manufacturers, charge $150 an hour.
According to the Remodeling Futures program, as of 2011, nearly half of all United States home improvement spending came from homeowners over 55 (10 years ago, they were responsible for less than a third of it).
Although most owners 55 and older have a bedroom on the first floor to avoid stairs, only a third have wheelchair-accessible kitchens, and fewer than one in six have raised toilets, lever door handles rather than knobs, or wider doorways and hallways for easier navigation, according to the Harvard report.
To prepare for this job, Certified Aging-in-Place Specialist courses from the National Association of Home Builders teach design and building techniques for making a home accessible to all ages. The program consists of three individual classes that cover such things as design basics, building standards, how to do a home assessment and the best methods to market services. Total fees for the combined courses are typically under $1,000.
Many in the program are professional builders and remodelers, but interior designers and occupational therapists enroll, too. Even landscape designers take it to help them create retiree-friendly gardens and outdoor spaces in private residences.
Surprisingly, according to Jeff Jenkins, the home builders' association's director of education, women make up a large share of those who attain the designation.
Courses are offered at N.A.H.B.-sponsored events like the annual International Builders' Show and the Remodeling Show in the fall. They are also scheduled at builder association locations across the country. Every three years, continuing education is required to maintain the designation.
"There is so much more than stairs and tripping hazards," Ms. Greenhouse said. To teach awareness of the environment and help her students understand what their clients are dealing with, she asks them to explore a living space with earplugs, or glasses with dark lenses smeared with petroleum jelly to simulate macular degeneration. They might ride around in a wheelchair or use a walker.
A profession complementary to Aging in Place home modifications is installing home automation systems. "If Grandma has a system where she can see who is at the front door via video, can unlock the front door remotely, can control her heating, cooling, window shades and lighting from a tablet, that is an enormous step for safety and independence," Ms. Greenhouse said. Go to the Custom Electronic Design and Installation Association for training and information.
For those downsizing to smaller quarters later in life -- usually an apartment or retirement community -- a move manager can coordinate a move and configure a new home setup.
Clients need advice on choosing which furniture, collectibles and household goods make the cut to head over to the new residence. A move manager can assess what can be sold, donated or given to friends and family, and might even be in charge of shopping for new furniture that suits the new home, or organizing and running an estate or yard sale.
This job calls for configuring and cajoling, and the moves involved are fraught with emotion. A calm but take-charge demeanor is a desirable personality trait.
Fees range from $30 an hour to more than $75. Knowledge of interior design is essential. A relationship with a real estate agent can jump-start your business as well as provide a steady clientele down the road. For more information on courses and certification, contact the National Association of Senior Move Managers.
For leads on jobs, move managers can stop by real estate offices and visit retirement and assisted-living communities to ask about their future residents' needs. Find out who is handling this type of work for them. The community's management office usually provides arriving residents with suggestions for moving specialists to lend a hand with what can be a daunting endeavor for downsizers of any age.
Last fall, Kelly Lonigan, a 71-year-old former clinical social worker who lives in Sacramento, decided to "unretire" after five years out of the job market.
On the radio, she heard an interview with a cancer patient who said the best $4,500 he ever spent was to hire a patient advocate to help him deal with his health care.
That clicked with her. She looked up "patient advocate" online, and the patient advocacy certificate program from Empowered U.C.L.A. Extension came up on her screen. "My heart just opened. This is something I can get my heart into again," Ms. Lonigan said.
The role of patient advocate varies. Some advocates tackle billing mistakes and insurance coverage rejections. Others might help in choosing doctors, offer guidance in treatment choices, assist in locating a specialist or hospital, go with patients to doctor appointments and keep track of prescriptions.
Job opportunities might include working privately for one person or a couple, or working on staff as an advocate or patient navigator at a hospital. Fees vary from $15 up to $150 an hour.
Empowered U.C.L.A. Extension is an online education company that offers fast-track certificate programs for older adults. These 20- to 25-student classes are taught on an iPad screen through an app that delivers audio, face-time video and discussion boards.
Once enrolled, students meet with their career counselors as often as they like, through face-to-face video chats, phone calls, e-mail and group webinars. Dedicated career counselor support will last for two years starting when the first school bell rings.
"I know I'm pushing my neurons," Ms. Lonigan says. "And that's a good thing at my age."
To enroll in Empowered's Patient Advocacy certificate program, you need a bachelor's degree in any field, or an associate degree in nursing, respiratory therapy, occupational therapy (assistant) or physical therapy (assistant). Tuition is $7,400.
Community colleges and nonprofit organizations also are developing training and certification programs for patient advocates. Nurses, social workers, medical professionals and insurance experts are in high demand for these positions. But someone who has steered his or her own hair-pulling path, or a parent or partner's, through the medical system might be the perfect person to take on this role.
No licenses are required, but there are credential programs available. Contact the National Association of Healthcare Advocacy Consultants in Berkeley, Calif., and the nonprofit Patient Advocate Foundation for information. The Master List of Health and Patient Advocacy Educational Courses, Programs and Organizations is a good resource for workshops and courses across the country.
Get-up-and-go and good communication skills are prerequisites. Trainers teach group classes and one-on-one sessions that typically run 45 minutes to an hour. An understanding of human physiology, proper exercise practices and an ability to judge a client's fitness level is essential.
Aqua aerobics is a growing specialty, as is "accessible" yoga, which adapts techniques for people with chronic illness and disabilities. Instructors tweak traditional yoga positions for people who are in a chair or wheelchair or have other physical issues.
Hours are generally flexible. Pay is $17 to $30 an hour, but in larger cities, rates can increase to $60 or more. Most health clubs collect the cost for the session from members and dole out a percentage to you.
Certification is not required by law, but most fitness clubs require it. Several groups offer some type of credential. These include the Aerobics and Fitness Association of America, the American Council on Exercise, the International Sports Sciences Association, the National Exercise Trainers Association, the National Strength and Conditioning Association, Y.M.C.A. Silver Sneakers and the Arthritis Foundation.
Such programs cost about $200 to $400 and usually consist of a written test and a practical exam. For all credentials, an additional certification in cardiopulmonary resuscitation is required. Insurance might also be necessary.
At the Y in Chelsea, Ms. Brown says fitness instructor is her dream job, after three decades working in the garment industry. She leads 17 classes a week in groups of 15 to 40 older adults at a variety of locations and earns about $40 to $50 an hour.
She is gratified when she sees a client who once was unsteady on her feet gradually growing steadier and more confident. "There's a certain vitality that shows through in their smiles that's hard to describe, but it's magic," Ms. Brown said.
Kerry Hannon is the author of "Great Jobs for Everyone 50+: Finding Work That Keeps You Happy and Healthy ... and Pays the Bills" (John Wiley & Sons)
This article originally appeared in The New York Times.