An analysis of the experiences of more than 1,700 women who were involved regularly in helping others highlighted the physical effects experienced by frequent helpers. The magazine Better Homes and Gardens surveyed readers, asking them to write about their experiences: how often they helped, and their feelings, if any, when helping. They were also asked about their current health. As part of the study, the Institute for the Advancement of Health surveyed 1,500 members of a large women's volunteer group. Frequent helpers described a physical experience similar to that had by people who exercise vigorously or meditate. Endorphins are released during positive social contact with others, creating the opposite of the body's agitated condition under stress. Altruism needs to involve direct contact with others, and must be voluntary, to produce the effect.