After making it through the maelstrom of middle age, many adults find themselves approaching older age and wondering, "What will give purpose to my life", now that the kids have flown the nest and retirement is on the cards?

How they answer can have significant implications for their health.

Over the past two decades, dozens of studies have shown that seniors with a sense of purpose in life are less likely to develop mild cognitive impairment, Alzheimer's disease, disabilities, heart attacks or strokes. They are also more likely to live longer than people without this kind of underlying motivation.

A report in Jama Psychiatry adds to this body of evidence by showing that older adults with a solid sense of purpose tend to retain strong handgrips and walking speeds - key indicators of how rapidly people are ageing.

Why would a psychological construct ("I feel that I have goals and something to live for") have this kind of impact?

Seniors with a sense of purpose may be more physically active and take better care of their health, some research suggests. They may also be less susceptible to stress, which can fuel dangerous inflammation.

"Purposeful individuals tend to be less reactive to stressors and more engaged in their daily lives, which can promote cognitive and physical health," said Mr Patrick Hill, an assistant professor of psychological and brain sciences at Washington University in St Louis, who was not involved with the latest study.

But what is purpose, really? And how can it be cultivated?

Dr Anne Newman, 69, who splits her time between Hartsdale, north of New York City, and Delray Beach, Florida, said she has been asking herself this "on a minute-by-minute basis" since closing her psychotherapy practice last year.

Building and maintaining a career became a primary driver in her life after she raised two daughters and returned to work at age 48.

Experts advise people seeking a sense of purpose to consider spending more time on activities they enjoy or using work skills in a new way.

Dr Newman has explored work and volunteer opportunities in Florida but nothing has grabbed her yet. "Not knowing what's going to take the place of work in my life - it feels horrible, like I'm floundering," she admitted.

Many people go through a period of trial and error after retirement, said Dr Dilip Jeste, senior associate dean for healthy ageing and senior care at the University of California at San Diego.

"People don't like to talk about their discomfort because they think it's unusual. And yet, at this time of life, everybody thinks about this question, 'What are we here for?' " he said.

Dr Newman's focus has been on getting "involved in something other than personal satisfaction, something larger than myself".

But that may be overreaching.

"I think people can get a sense of purpose from very simple things - from taking care of a pet, working in the garden or being kind to a neighbour," said Dr Patricia Boyle, a professor of behavioural sciences at the Rush Alzheimer's Disease Centre at Rush University Medical Centre in Chicago.

"Even small goals can help motivate someone to keep going," she added. Older adults often discover a sense of purpose from taking care of grandchildren, volunteering or becoming involved in community service work or religion, she said.

"A purpose in life can arise from learning a new thing, accomplishing a new goal, working together with other people or making new social connections," she said.

After Mr Barry Dym, 75, retired a year ago from a long career as an organisational consultant and a marriage and family therapist, he said: "I didn't ask myself, 'Do I have a larger purpose in life?'

"I asked myself, 'What gives meaning to my life?'"

Answering that question was not difficult.

"What gives meaning to me is helping people. Trying to have an impact. Working with people and helping them become much better at what they do," said Mr Dym, who lives in Lexington, Massachusetts.

In retirement, he is mentoring several people with whom he has a professional and personal relationship, bringing together groups of people to talk about ageing and starting a blog.

"I feel of two minds about purpose in older age," he said. "In some ways, I'd like to just shuck off that sense of having to do something to be a good person and just relax. And in other ways, I feel deeply fulfilled by the things I do."

THE WASHINGTON POST