In a study testing whether the relationship between exercise and health is moderated by one's mind-set, 84 female room attendants working in seven different hotels were measured on physiological health variables affected by exercise. Those in the informed condition were told that the work they do (cleaning hotel rooms) is good exercise and satisfies the Surgeon General's recommendations for an active lifestyle. Examples of how their work was exercise were provided. Subjects in the control group were not given this information. Although actual behavior did not change, 4 weeks after the intervention, the informed group perceived themselves to be getting significantly more exercise than before. As a result, compared with the control group, they showed a decrease in weight, blood pressure, body fat, waist-to-hip ratio, and body mass index. These results support the hypothesis that exercise affects health in part or in whole via the placebo effect.
A study like this makes you wonder how much of the benefit of physical education regimes like yoga, pilates, etc.- versus just being active - are due to such a placebo effect.
Before I am willing to believe this article and its attendant implications, I'd want to know how the authors verified that the behavior of the "informed" group did not change relative to the control group. I could easily imagine that the "informed" group, having been provided with examples of how their jobs contain elements promoting physical fitness, then spent more time and energy on those aspects of their jobs. That is, the "placebo" information could easily have altered their behavior in subtle but significant ways. It is worth noting that the data necessary to measure such a behavioral change would be extremely difficult to acquire. Unfortunately, my institution does not have a subscription to the journal, so I can't verify this myself, but the claim is weak without such a control.
ReplyDeleteYou make a very good point. I have edited the post to now include a PDF download of the study. Their rebuttal of your critique sounds a bit lame:
ReplyDelete"Of course, it is possible that the room attendants actually did
change their behavior—actually did cut back on calories, improve
the quality of the food they ate, or work harder or more
energetically—but did not report such changes. However,
previous research has found it very difficult to change behavior
of this sort (Deutschman, 2005). Thus, even if these behavioral
changes did occur as a result of the intervention, that too would
make these results interesting."
Ack! I missed that pdf link on the first run through the blog post. The following quote answers my question:
ReplyDelete(begin quotes)
It was assumed, and later confirmed by the hotel housekeeping managers, that the workload of the room attendants remained constant in the 30 days prior to and the 30 days during the study. Therefore, if there was no increase in reported exercise outside of work, any increase in perceived regular exercise, perceived amount of exercise, or perceived work as exercise would be assumed to reflect a change in mind-set initiated by the intervention and not due to an increase in actual exercise.
Also:
They were given specific details of the average calorie expenditure for various activities (changing linens for 15 min burns 40 calories, vacuuming for 15 min burns 50 calories, and cleaning bathrooms for 15 min burns 60 calories), and they were told that although these figures were based on results for a 140-pound woman and each of them would burn calories at a different rate, it was clear that they were easily meeting and even exceeding the Surgeon General’s recommendations. 2 This sheet, written in both English and Spanish, was read and explained to the subjects and then posted on the bulletin board in their lounge.3
And finally:
Of course, it is possible that the room attendants actually did change their behavior—actually did cut back on calories, improve the quality of the food they ate, or work harder or more energetically—but did not report such changes.8 However, previous research has found it very difficult to change behavior of this sort (Deutschman, 2005). Thus, even if these behavioral changes did occur as a result of the intervention, that too would make these results interesting.
(end quotes)
These workers ate their lunch every day staring at a big poster extolling the physical benefits of their daily routine. It is easy to believe that this could have induced them to make beds or scrub bathrooms a little more vigorously, which would certainly have a nontrivial cumulative effect over the course of 20 8-hour days.
The placebo effect need not be some sort of magic mind-over-matter to be effective. One can similarly imagine that the effect of placebos on pain perception is as much due to subjects actively managing the focus of their attention as anything else. Placebo stimulants could similarly operate through conscious control of attention.
Of course, this is just rampant speculation on my part, but I'm just posting it as a comment in a blog, rather than trying to publish it in a peer-reviewed journal.
They probably did the information sessions during the women's lunch hours.
ReplyDeleteInterventions have been used to address serious personal problems, including, but not limited to, alcoholism, compulsive gambling, drug abuse, compulsive eating and other eating disorders, self-mutilation, tobacco smoking, "workaholism", and various types of poor personal health care.
ReplyDeleteInterventions have also been conducted due to personal habits not as frequently considered seriously harmful, such as video game addiction, excessive computer use and excessive television viewing.
Direct and indirect interventions
Drug Intervention New Mexico