Far from being frail recluses, many of today's centenarians are nearly as physically and socially active as their baby boomer grandkids, a new survey finds.

Two-thirds of centenarians exercise nearly every day and read newspapers, books and magazines; one-third work crossword or number puzzles -- all similar to boomers.

The seventh annual 100@100 survey of 100 centenarians, sponsored by UnitedHealth Group of Minnetonka, also asked questions of 300 baby boomers this year.

The survey did not include centenarians whose physical or mental frailties prevent them from responding, so it represents a healthier slice of the estimated 72,000 Americans in their 100s. The Census Bureau estimates that number will grow to more than 600,000 by 2050.

"While genetics and maintaining a healthy body are important factors in living well into the 100s ... staying socially engaged is just as important to healthy aging," said Dr. Rhonda Randall, chief medical officer of UnitedHealthCare Medicare & Retirement.

Among other findings:

• A majority of both groups say the age to qualify for Medicare and Social Security should not be raised, but they expect that to happen.

• More centenarians eat nutritious meals (81 percent) and get eight or more hours of sleep a night (71 percent) than boomers. Almost the same number laugh each day (80 percent) and pray or meditate (67 percent).

• The share of centenarians with Internet access has doubled since last year, to 25 percent. Among that group, about half use e-mail and share photos.

But what's most important? Physical health, more even than mental or emotional health, say the largest share of both boomers and centenarians. To help maintain that health, centenarians walk (44 percent), exercise to strengthen muscles (41 percent), work in gardens (23 percent) and even run outdoors (5 percent).

To read the report, go to www.startribune.com/a1384.

wolfe@startribune.com.• 612-673-7253