Will you really be able to work into your 70s?

Seven years ago, when nearing 70, Dr. Samuel Lupin planned to retire from being a solo physician making house calls to elderly patients. Then his grandson Daniel Stokar, a recent Yeshiva University business school grad, approached him with an intriguing proposition: Let's tether modern telecommunications to your geriatric care practice.

Lupin agreed to delay his retirement for six months while Daniel developed the Brooklyn-based venture. A year later, Daniel's father Avi joined up, creating its IT system. The three-generation enterprise, Housecalls for the Homebound, now operates in all five boroughs and has treated more than 4,000 homebound patients. Lupin puts in five to 10 hours a week as the company's medical director.

What about his plan to retire? "I may just stay the way I am for the foreseeable future," he told me. "It is such an unbelievable pleasure to see the project as it evolves and continues to expand." Little wonder Lupin won one of Encore.org's Purpose Prizes, for people over 60 who combine "their passion and experience for social good."

That's great for Lupin. But what about the rest of us? Can we really expect to be able to keep working into our 70s if we want or need to? In Bankrate's latest Financial Literacy poll, three-quarters of U.S. workers said they believe "work is the new retirement." And 72 percent of pre-retirees surveyed by Merrill Lynch and the consulting firm Age Wave planned on working in retirement.

That may be the public expectation. But scratch the surface and you hear something different.

When I go around the country giving talks about my book "Unretirement," I often hear boomers nervously worrying that the accumulated wear, tear and infirmities of aging will prevent them from working into their 70s.

Their skepticism is understandable. But I believe the fear over winding up with debilitating disabilities is exaggerated. On the other hand, I think the job opportunities for people in their 60s and 70s who do have disabilities are underemphasized.

Take the federal government's report, "Older Americans With a Disability: 2008 – 2012," which defines disability as having one or more of these "difficulties:" hearing, vision, cognitive, ambulatory, self-care and independent living. Almost 74 percent of those 65 to 74 had no disability by these measures and another 14 percent had only one. These figures strongly suggest the fear that older folks are too frail and disabled to stay employed is exaggerated.

Even the 75-to-84 age group fared surprisingly well: 55 percent had no disability and almost 19 percent had only one. (The big downward drop comes at 85-plus. Among that group, only 27 percent had no disabilities while 41 percent had three or more.)

Even more striking, between 1982 and 1999, the prevalence of physical and mental disabilities among older Americans declined. Among the factors driving the improvements: advances in medical treatments (such as beta blockers and ACE inhibitors for cardiovascular disease), less smoking and rising education levels.

"We are pushing to older ages the onset of disabilities," says Neil Mehta, professor at the Rollins School of Public Health at Emory University. "It's a promising sign."

Unfortunately, worrisome trends are emerging. The improvements in disability have flattened out since 2000, and researchers have detected a modest increase for the 55-to-64 group.

This leads me to the risk we should really be worrying about. We aren't focusing enough on ways to make it easier for older Americans with disabilities to work if they want to. "I think there is an increase in labor force participation that can occur for older Americans," says Mehta. "How can we think about enabling or tapping into that potential with policy?"

Here are a few possibilities: Increase investments in public transportation. Bring universal design into more workplaces (taking aging and disabilities into account with appropriate door handles, lighting, work surface heights and the like). Allow for flexible schedules on the job. Researchers have learned that greater control over schedules helps employees with disabilities do their work better, keep their doctor appointments and stay healthier.

"Disability accommodations in the workplace could encourage employment among older adults with limitations," concludes Diana Kachan, public health professor at the University of Miami's Miller School of Medicine and her eight co-authors in their study, "Health Status of Older U.S. Workers and Nonworkers, National Health Interview Survey, 1997–2011."

Here's the kicker: Some researchers have discovered that accommodating workplaces for disabled older workers improves the health of older workers overall. "Continuing some form of paid work in old age is one way to ensure a healthier population," writes Gabriel Sahlgren, director of research at the Centre for Market Reform of Education in London, in "Work Longer, Live Healthier."

This doesn't mean that Americans should work full time till they drop dead. Nor am I putting forward a Pollyannaish perspective that everyone can work well into their 70s. At some point, infirmities will slow down most boomers.

So let's tackle the real risk: not exploiting the opportunities that could be opened up if we invest in those goals for an aging population.