For years, researchers have known that our physical and mental well-being improves when we freely give our time to help others. And when we do so through company-sponsored programs, performance-related outcomes like job satisfaction and commitment to work also get a boost.

But there has been little agreement among experts on why this should be the case.

Recently, however, professors Jeffrey Pfeffer and Sara Singer of the Stanford Graduate School of Business analyzed survey data from hundreds of businesses in the United Kingdom to tease out the mechanisms through which volunteering improves both employee health and organizational outcomes. (The data were collected through Britain’s Healthiest Workplace and includes more than 53,000 employee responses.)

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