Retirees who are part of social clubs are likely to live for longer, a new study suggests.
The benefits of book clubs and church groups equal to those of regular exercise, researchers have claimed.
The more clubs a person belongs to in the first few years after they stop working, the lower their risk of death, they found.
People who are part of clubs are also more likely to have a better quality of life, the researchers said.
Finishing work is a major life change and previous studies have suggested that people's health and wellbeing can deteriorate after retirement.
In a bid to assess the impact of social groups on retirees, researchers examined almost 424 English adults over the age of 50 for six years after retirement. They were compared with the same number of people, matched for age, sex, and health status, but who were still working.
Each participant was asked how many different organisations, clubs, or societies they belonged to and also answered questions on their physical health and quality of life.
The study, published in the online journal BMJ Open, found that 6.6% of the retiree sample died in the first six years after they finished work.
Retirees who had two group memberships before retirement had a 2% risk of death in the first six years of retirement if they maintained membership in two groups, a 5% risk if they lost one group and a 12% risk if they lost both groups, the researchers found. No such patterns were seen for those still in formal employment.
Researchers also assessed whether changes in physical activity levels affected risk of death.
They found that if a person exercised vigorously once a week before retiring and maintained this frequency post-retirement, they had a 3% chance of dying in the next six years, a 6% chance if they decreased this frequency to less than weekly and an 11% chance if they stopped exercising vigorously altogether.
"Accordingly, we can see that the effects of physical activity on health were comparable to those associated with maintaining old group memberships and developing new ones," the researchers wrote.
The authors also concluded that for every group membership that participants lost in the year following retirement, their quality of life six years later was approximately 10% lower.
They wrote: "Retiring from work constitutes a major life transition that most people experience at some point in the course of their life, posing significant challenges to health and wellbeing.
"The number of groups that retirees are members of is a predictor of both their subsequent quality of life and their likelihood of dying; being as good a predictor as physical activity."
Janet Morrison, chief executive of charity Independent Age, said: "This research underlines the importance of making sure older people stay connected to their communities.
"It's yet more evidence that having a sense of purpose and taking part in meaningful activity can make a really positive difference to health and wellbeing in later life."
She added: "As the population ages and family structures change, combating loneliness is increasingly going to become a pressing public policy issue, and it's important that much more is done to tackle this issue."
Caroline Abrahams, charity director at Age UK, added: "The fact that so many of us are living longer is a good thing but it is important that older people are encouraged to stay engaged in their community.
"Even small amounts of physical activity can make a difference to a person's health and can lower the risk of serious conditions such as strokes, heart disease and certain cancers. Not only does exercise add years onto our lives but it can make you happy and helps maintain independence. Societal attitudes must shift so being inactive is not thought of as the norm for our later years."