Doing good for others warms the heart—and may protect the heart, too. Psychologists at the University of British Columbia asked 106 high school students to take part in a volunteering study. Half of the students spent an hour every week for 10 weeks helping elementary students with homework, sports or club activities. The other half of the students did not participate in volunteer work.

Using questionnaires and a medical examination both before and after the 10-week period, the researchers found that students who volunteered had lower levels of cholesterol and inflammation after the study. Those who did not volunteer showed no such improvements.

Click here to read article in Scientific American.