People who volunteer — whether it is at schools, food banks, hospitals, business development organizations — are doing more good than they know. In addition to the benefits to the people or organizations who receive volunteers' time, helping others also improves their health.

Volunteer work reduces the risk of hypertension, or high blood pressure, a leading cause of heart disease, according to a recent study at Carnegie Mellon University.

The specific type of volunteer activity was irrelevant; only the amount of time spent volunteering led to a decreased risk of hypertension.

“When we think of volunteer work, we tend to think about how volunteering affects other people and helps others,” Rodlescia Sneed, corresponding author on the study, told TheDoctor. But this study shows that volunteering can actually be good for the volunteers, “It gives older people something that they can actively do to maintain their health, that has nothing to do with taking medication.”

Sneed, a doctoral candidate, and Sheldon Cohen, Professor of Psychology, studied 1,164 adults between the ages of 51 and 91 from across the country. The participants were interviewed twice, once at the start of the study and then again four years later. Volunteerism and a variety of social and psychological factors were discussed in the interviews, and subjects' blood pressure was measured. All had normal blood pressure levels at the first interview.

At the end of the four-year study, investigators found that those who had reported at least 200 hours of volunteer work at the first interview were 40 percent less likely to develop hypertension than those who did not volunteer. The specific type of volunteer activity was irrelevant; only the amount of time spent volunteering led to a decreased risk of hypertension.

The researchers found no psychological or behavioral explanations for why volunteer hours were associated with lesser hypertension risk. Among the possible explanations is that volunteer work may make people feel good about themselves, help them to be more socially connected, and provide a sense of accomplishment.

“As people get older, social transitions like retirement, bereavement, and the departure of children from the home often leave older adults with fewer natural opportunities for social interaction,” Sneed says. “Participating in volunteer activities may provide older adults with social connections that they might not have otherwise. There is strong evidence that having good social connections promotes healthy aging and reduces the risk of negative health outcomes.”

The study is published online in Psychology and Aging.