Gone are the days when retirement was associated with a rocking chair. Older millionaires are returning to the workforce or redirecting their energy to volunteer work and travel, according to the Northern Trust Wealth in America 2007 survey released April 2.

Among the 1,002 respondents to an online survey conducted last November and December, 48 percent said they were retired, but 29 percent have returned to the workforce—18 percent part time and 7 percent full time, with 4 percent looking for work. Among respondents older than 70, one in six remains in the workforce, either rejoining the ranks of the working after retirement or never retiring at all.

“Retired business owners and executives tell us that they want to give back the knowledge they’ve gained during their careers,” said Gregg Yaeger, head of the Financial Consulting Group at Northern Trust. “And many continue to explore and start or invest in new ventures.”

Seventy-six percent of respondents said ensuring a comfortable standard of living was a key retirement issue, while health-related issues, both financial and physical, also ranked as top concerns. The study found that 64 percent of millionaires believe it is important to pursue personal interests and hobbies in retirement; 61 percent want to travel; 53 percent desire an active lifestyle; 30 percent want to volunteer in their communities; and 30 percent would like to continue their education.