FORT LAUDERDALE, Fla. - Ruth H. Clark of Pompano Beach, Fla., is a 95-year-old aerobic wonder, working out seven days a week.

But Clark is not just flexing her muscles, she's protecting her retirement nest egg by staying healthy.

Economists say health care will become more crucial in retirement planning as medical expenses climb for the elderly.

People on Medicare already spend three times more as a percent of income out-of-pocket for health care compared to non-Medicare households - 14.7 percent vs. 4.9 percent, according to the National Council on Aging.

"The financial burden is highest for beneficiaries who are older, in relatively poor health, and have low or modest incomes," said council spokesman Ken Schwartz.

Medicare recipients 85 and older spend an average of 30 percent of their income for out-of-pocket medical expenses, or $4,615 a year, according to an analysis on the website New Retirement.com. Many seniors who have higher retirement savings and income pay even more.

The nonprofit Employee Benefit Research Institute estimates a 65- year-old couple will need $271,000 to give themselves a 90 percent chance of having enough savings to cover their out-of-pocket medical expenses during retirement.

By staying out of the hospital, Clark has saved tens of thousands of dollars in medical costs, from hospital bills to paying for home- health-care nurses. For example, she "treats" arthritis by bending, stretching and moving about during her daily 30-minute workouts. She adds 2-pound weights to her regimen every other day.

"Every single joint gets moved," Clark said.

She also sticks to mostly fruits and vegetables. She has avoided diabetes, heart problems and other chronic ailments, partly thanks to such a healthy diet.

"The best thing to do is keep your health," said Jorge Salazar- Carrillo, an economics professor at Florida International University.

Seniors might end up paying more of their medical expenses, especially higher-income retirees, Salazar-Carrillo said. Some experts believe Medicare's hospital portion will go broke as soon as 2016.

Others, especially Baby Boomers, will need to stay healthy so they can work longer and avoid retiring to allow their nest egg to keep growing, added Tony Villamil, dean of the school of business at St. Thomas University.

"Your health is critical to postponing your retirement," Villamil said.

- Sun Sentinel