For older adults, the medical screening that all applicants must undergo can be prolonged. “We have to look at the individual’s health history, the conditions in the host country and the medical support available,” Ms. Lartigue said. “Your apartment in Ukraine may be on the fifth floor with no elevator  can you climb those stairs day in and day out?”

Leslie Michael, 59, of Columbia, S.C., first thought of joining the Peace Corps in college but instead embarked on a 31-year career in elementary education. Seven years ago, she learned that she had breast cancer, and the Peace Corps idea resurfaced. She waited five years after completing her cancer treatment and applied.

“The application process was not difficult, but the medical screening was awful,” she said by e-mail. “At first, I was rejected because I have rheumatoid arthritis, but I appealed and was finally accepted.”

After four weeks of training in Namibia, including site visits and job shadowing, she lived with a family for several weeks for cultural and language training and is now training preprimary teachers in Swakopmund.

The Peace Corps provides volunteers with comprehensive health coverage; round-trip transportation to the placement destination; a monthly stipend to cover rent, food, clothing and transportation; and an accrued allowance paid at the end of service. Volunteers also receive job- placement support and preferential treatment if they apply for federal jobs.

Older adults whose children have left home and who have completed their primary careers are ripe for what gerontologists call life review and new challenges, said Dr. Carl Eisdorfer, director of the Center on Aging at the University of Miami. “You start asking, ‘What have I done with my life?’ For some people, life has been good, and there’s a tendency towards altruism. What better way to do that than spend time in another culture where your skills have value?”

Image OLD LOTUS In her Thai village Jacqueline Kehl, with dancers, draws attention for her short gray hair. Credit... Courtesy of Jacqueline Kehl

And in some traditional cultures, gray hair and a few wrinkles can enhance respect. “I’m taken more seriously and can say what I think without anyone getting angry with me,” Ms. Michael said.