Experts often call it the "invisible problem," because the shortage of doctors in the U.S. is not as conspicuous or talked about as much as home foreclosures or job losses.
But the growing scarcity—most specifically of primary care physicians—is clear for patients who sit for hours in waiting rooms, must drive long distances to a physician's office or simply can't find a doctor.
Some observers say that the shortage is a major threat to the nation's health care system.
"The shortage is here now and getting worse all the time," said Dr. Michael Saag, director of AIDS Research at the University of Alabama, Birmingham.
"There have been many stories about it, but we've really had this problem over the last 30 years, and unless we do something soon, we're facing a real crisis in health care," Saag said. "And the shortage is in all areas of medicine."
'It's an economic problem," said Dr. Joel Blass, a primary care physician at the Workmen's Circle MultiCare Center in The Bronx.
"You have so many slots in medical school that can be filled, and then you have uneven distribution. You don't necessarily see the shortage in New York but more in the rural areas, where there are fewer doctors and more patients," Blass said.
The U.S. is estimated to be short about 16,000 primary care doctors. That leaves about 55 million people without a doctor or struggling to find one.
(Read More: Applying for Obamacare Health Insurance Not Easy)
The Association of American Medical Colleges predicts bigger shortages in all types of physicians: 63,000 by 2015 and 130,600 by 2025.
One reason for the shortage is the aging of both doctors and their patients.
According to a 2012 Physicians Foundation survey, nearly half of the 830,000 doctors in the U.S. are over 50 and approaching retirement. They are also seeing fewer patients than they did in 2008.
The patient pool is getting older, too, with some 8 million people reaching retirement age every day. Older people need more health services, and some 15 million will be eligible for Medicare in the coming years.
Entering the system in 2014 will be the 30 million additional people with access to services through the Affordable Care Act (Obamacare).
"There were shortages in doctors when Massachusetts did their version of the Affordable Care Act," said Ruselle Robinson, a health care business attorney and former general counsel to the Massachusetts Department of Public Health.
"It's hard to say how this will play out with all the new people being added to health care next year," Robinson said.
Younger doctors are also part of the shortage problem. Saddled with medical school debt that can average $250,000 on graduation, many are choosing higher-paid specialties like cardiology or surgery.
"When students leave med school a lot of them are thinking about how I can make the most money," Saag said. "Somehow, we have to figure out a way to reward primary care providers so more will enter that area."
One way to reduce such debt and get doctors into the system more quickly is accelerated education, making medical school three years instead of four — something that is not new but not widely followed.
NYU has such a program now, as does Texas Tech, which is graduating its first class this year under the new schedule. It takes nearly a decade to educate a doctor and the hope is one less year would help cut down on the financial burden.
(Read More: College Roulette: Ask for Financial Aid, or Not?)
"It's not clear yet as to whether this is a good model and how viable it will be," said Dr. Andew Filak, senior associate dean at the University of Cincinnati College of Medicine.
"For some students, three years would be adequate," Filak said. "For others, some more time might be necessary to assure that the student has the fundamental knowledge and experience to move on to a residency program."
Other solutions include letting nurse practitioners be more involved at the primary care level. Sixteen states now allow them to see patients for checkups, and ordering and interpreting diagnostic tests.
Some would like more states to adopt similar programs.
"We need to have a lot more nurse practitioners on the job," said Terry Fulmer a nurse and the dean of Bouve College of Health Sciences at Northeastern University.
"Obviously, they don't have the education of a physician, but they are highly trained professionals. And if the outcome is equal to what a doctor would do, it doesn't matter how many hours' training a nurse has," Fulmer said.
Another way to work around the doctor deficit is more team-based care, in which a physician-led team of at least two health care professionals (nurses and doctors) work with each other, the patient and the family.
Getting more medical professionals into the pipeline won't be easy. Though Obamacare authorized more government funds to increase training for primary care doctors, nurse practitioners and physician assistants, that money is set to be cut in the ongoing budget battles.
(Read More: Your Company's Next Health Plan: Drop the Doughnut)
There is some hope. More than 45,000 students applied to medical school last year, up 3.1 percent from 2011. First-time applicants, considered to be a barometer of interest in the field, set a record, increasing by 3.4 percent.
"I think more medical students these days are going in with their eyes wide open and for the right reasons," said Dr. Joel Blass.
"Even dealing with all the regulatory and insurance requirements, I think it's all moving in the right direction," Blass said.
And one expert says it's not so much a scarcity of physicians but of using them in the right way.
"We don't need more physicians, but rather better "team-based workflow tools" to ensure that everyone on the team can work to the highest level of their ability in a safe and efficient manner every day," said Dr. Lyle Berkowitz, Associate Chief Medical Officer of Innovation for Northwestern Memorial Hospital.
"That means using information technology and freeing physicians to spend their time on more complex patients," Berkowitz added.
But many physicians are questioning their profession. In a recent survey of U.S. doctors, more than 84 percent said the profession was in decline. Nearly 60 percent said they wouldn't recommend medicine as a career.
More than 75 percent said they were overextended and as result, nearly 6 percent of doctors said the were working fewer hours than they did in 2008.
"Our medical system is in chaos, and the shortage is part of it," Saag said, who added that Alabama and other nearby states have a shortage of HIV specialists.
"Whether it's getting more doctors or a health care system we can all understand, something needs to change and soon."