A recent German study published yesterday claims that volunteering not only offers mental health benefits, but may in fact help employees to perform better at their 'real' jobs. The study followed 105 full-time employees who also devoted between 5 and 10 hours to volunteering each week. Based on extensive surveying and questionnaires, the study found a positive relationship between those who felt both satisfied at work and those who spent the most time volunteering. The study claims that the more employees volunteer, the more likely they are to feel their 'work needs' satisfied, and to be able to draw on learning experiences. In general, the study also found that those who volunteer more listen better when at their paying jobs.
See "Volunteering can bring rewards even in the workplace", Robert Preidt, Business Week, February 16, 2010