There are few better examples of the health benefits of volunteering than Leung Fong - who is still teaching knitting at the age of 86, six years after having a cardiac pacemaker fitted.
For the past four years she has been teaching more than 100 elderly people how to knit at the West Garden Social Centre for the Elderly as part of a scheme set up by the Agency for Volunteer Service.
The grandmother began to have heart problems soon after the death of her husband six years ago and doctors decided that she would need the pacemaker to keep blood flowing through her body properly.
Now, she's convinced she would be getting on just fine without the pacemaker - and her doctors have told her they do not plan to replace it after its 10-year lifespan is up.
"The doctor asked if I was very happy or not, and I answered him yes, saying that I knew many friends in the centre," Leung said with a cheerful smile. "I am so healthy that my heart can pump blood by itself."
She says volunteering also enhances her creativity and awareness, as she is constantly on the lookout for new styles that she could teach as part of the course.
"When I go shopping, or watch television programmes such as the Korean series, I will keep an eye on their clothing," she said.
Leung is well aware that life for many elderly people can be solitary and reclusive, and she says volunteering is a perfect alternative to staying at home, as it will help the person feel younger and happier.
Had she known the positive impact volunteering could have, she said, she would have taken part earlier.
As well as giving her two-hour knitting lesson, Leung enjoys taking classes from other elderly volunteers in Cantonese opera, English and dancing. But it's her own lessons that give her the most happiness.