Some Exercise Benefits May Be Placebo

Many of the beneficial results of exercise may be due to the placebo effect, according to a study of U.S. hotel housekeepers.

Study leader Harvard University psychologist Ellen Whether and student Alia Crum studied 84 female housekeepers from seven hotels. Women in four hotels were told that their regular work was enough exercise to meet the requirements for a healthy, active lifestyle, whereas the women in the other three hotels were told nothing.

Four weeks later the researchers returned to assess any changes in the women’s health. They found that the women in the informed group had lost an average of 2 pounds, lowered their blood pressure by almost 10 percent and were significantly healthier as measured by body-fat percentage, body mass index and waist-to-hip ratio, according to the study reported in Psychological Science.

These changes were significantly higher than those reported in the control group and were especially remarkable given the time period of only four weeks, say the researchers.

Whether the change in physiological health was brought about directly or indirectly, it is clear that health is significantly affected by mindset, said Whether.