Voluntary work for community groups or charities may help organisations, but research suggests it may not be good for the helper's health.
Volunteers felt their work did not benefit their own health
Researchers from Flinders University in Adelaide, Australia, asked over 500 people about involvement in voluntary groups.
They found that most of those who did voluntary work linked it with a negative effect on their health.
The study is published in the Journal of Epidemiology and Community Health.
The researchers found that over half of the people surveyed had been involved with a voluntary organisation in the last year.
Almost one in four had been involved in groups associated with sports or leisure, and a significant number had volunteered for work related, community, or social action groups.
Volunteers accepted there were benefits to the community as a whole, but only a few felt the work was of benefit to their own health, through factors such as the chance to meet new people, learn new skills, and be stimulated by the work itself.
Survey respondents were more likely to speak about the negative side of volunteering, such as witnessing difficult situations.
One in 10 felt that their own health problems would make it difficult for them to volunteer.
The researchers found that the broader the variety of groups someone was involved in, the worse their physical health was.
Older people seemed to be less negatively affected than younger people.
Writing in the journal, the researchers led by Dr Anna Ziersch, said: "This research indicates that involvement may not be beneficial for individual health, and that for the individuals involved there is some evidence that this involvement may in fact be detrimental for their own health.
"The relation is complex, and while we were able to consider some of the elements of the relation between civil society group involvement and health, there may be hidden differences between types civil society groups."
'Management is key'
Celia Richardson, of the Mental Health Foundation, told BBC News Online: "The benefits of work and the social inclusion it can bring are well known.
"Volunteering offers many similar benefits."
But she added: "Volunteering, like work, has to be structured and managed to ensure that stress is minimised.
"If people are feeling over-stretched or are witnessing depressing and difficult situations they aren't trained to deal with - and if they aren't offered appropriate protection or counselling - then it is not difficult to imagine they could feel there are negative health consequences attached to volunteering.
"Volunteering is best in an environment which is planned properly to maximise the benefits to the individual as well as the organisation."