Here's the dark cloud for the future:

From 1997 to 2007, more people age 50 to 65 said they needed help with daily living because of back or neck problems, diabetes or emotional problems.

Since then, the most common causes for needing help were these ailments as well as arthritis or rheumatism.

"There's a definite increase in the limitations on physical functions," says Linda Martin, a senior fellow at RAND Corp. and author of a study on mobility problems and aging.

While the increased numbers in people who need help are not horrific, about 2 percent, the study also found 40 percent of people ages 50 to 64 reported that because of health problems they had difficulty shopping, standing for two hours, walking a quarter mile or climbing 10 steps without resting.

If people need help in middle age, it could mean huge future expenses in caring for the elderly. Martin talked about the issues:

Q. Why is this happening to the younger boomers? Did they overdo exercise?

A. Maybe.

Q. Does this reflect changing job activity - more sitting and less physical labor?

A. Maybe. We are not sure why it's happening. The concern is, if you are going to need help with activities of daily living, as you age that is going to cost somebody. Whether it's family members, outside help, institutionalization.

The question is, what happens when these people get older?

Q. Sounds like you see a potential trend, but it's too early to tell?

A. More studies are needed to determine if these mobility issues reflect deterioration of health, improved diagnosis and treatment, of improved medical care that is extending the lives of those who might not have survived beyond age 50 in earlier decades.

These survey results are an early warning for society and also for individuals who may face limitations later on.

They have an opportunity to start early, to prevent or work in a way to reverse these mobility problems.

Q. Despite concerns about obesity in the United States, those needing help did not cite weight as an important cause of their limitations.

A. No. Instead, the analysis shows a prominent and growing form of diabetes as a cause of mid-life disability, suggesting the need to reduce the prevalence and disabling effects of the disease.

Also of concern is the growing role of depression, anxiety and emotional problems.

Q. Researchers say the study is the first to demonstrate that nervous system conditions are a growing cause of disability at midlife. This category includes many conditions, such as paralysis, migraine, epilepsy, multiple sclerosis and Parkinson's disease.

A. We definitely need more study.

Q. And what about those over 65?

A. While the younger aging population reports an increase in mobility issues, the over-65 population shows a decline.