Placebo Power: Can 'Thinking' Fit Get You Fit?

We're all familiar with the diet and exercise shysters on late-night TV. Whatever nostrum they are hawking at the moment, their promise is always a svelte and firm body with—here's the amazing part—absolutely no effort on our part. And all for just $49.99, major credit cards accepted. If you're like me, you tune out these grifters and go make a sandwich. We're no fools, and only a fool expects something for nothing.

But what if there's an element of truth in those wee-hour con games? What if you could, in fact, shed pounds and become healthier with no extra effort or changes in lifestyle? Scientists are highly skeptical of unproven health claims, but they are well aware of the strength of placebos—and what placebos demonstrate about the power of the mind in matters of health. Could a placebo possibly create a mindset that says, convincingly, "I am physically fit"?

Two Harvard psychologists decided to test the potency of such a placebo, but not in the traditional way. Placebos are usually thought of as "sugar pills"—inert tablets or sham procedures that convince people of their healing effects because they resemble regular medicine. But fake pills are just one way of packaging the placebo effect. Harvard psychology professor Ellen Langer and her student, Alia Crum, decided to explore the potential placebo effect of beliefs and expectations—specifically, beliefs and expectations regarding activity and health.

To do so, they visited several hotels in the Boston area, where they persuaded cleaning staff—all women—to take part in an experiment. Those who agreed were given a standard physical examination—measuring weight, body-mass index (BMI), blood pressure and so forth—and were interviewed about their habits, both at work and at home. The psychologists especially wanted to know about the maids' diet, exercise and activity levels.

Then they introduced the placebo. The psychologists told about half the maids that the tasks they performed every workday—making beds, cleaning toilets, etc.—was enough daily exercise to meet the U.S. Surgeon General's health recommendations. This is true. The Surgeon General in 1996 recommended that all American adults get at least 30 minutes of exercise daily, emphasizing that this goal could be met through such activities as walking, climbing stairs, doing yardwork and, yes, housework.

The maids in these hotels clean about 15 rooms a day. At 20 to 30 minutes per room, that's easily enough bending, lifting and folding to meet (and probably exceed) the government guidelines. But here's the key: the maids didn't realize they were getting a lot of exercise. Indeed, they didn't believe they were getting any exercise—not because they were stupid, but because it never occurred to them to think of it that way.

Langer and Crum told these subjects about the health benefits of exercise, and that exercise didn't have to hurt. They told them, even more specifically, how many calories are burned up by vacuuming a carpet or changing linens. The other maids in the experiment were also given physical exams; they were not, however, given any information about the health benefits of being a hotel maid. Then the scientists went home.

When the psychologists returned a month later, they repeated the physical exams. The results were unambiguous. As reported in the February issue of the journal Psychological Science, the now exercise-savvy maids not only perceived themselves as being healthier and more active than before, but they actually had lost weight, while improving BMI, fat distribution and systolic blood pressure. The uninformed maids showed none of these health benefits.

Although the enlightened maids' health gains weren't huge, they were real physical changes that took place in just one month. What's more—and this is very important—the positive effects occurred without any change in behavior. That is, these women were still cleaning 15 rooms a day; and away from work, they were eating and exercising as much as they had been before the experiment.

Thus, the only thing that changed—the only possible cause of the subjects' trimmer figures and better health—was mindset. So what exactly happened after these women revised their thinking about dusting and scrubbing, but before they stepped on the scale a second time? Langer, author of the influential 1989 book "Mindfulness," argues that people too often go through life mindlessly, rarely challenging their own (often wrong) certitudes. In the case of the hotel maids, they had been in relatively poor health simply because they didn't consider housework to be exercise. Once they discarded their old thinking, their health improved, suggesting that exercise affects health in part (or maybe even entirely) through the mind.

So, is it possible that we're all making the hotel maids' mistake, to a greater or lesser degree? Might we all get fitter and healthier if we just stopped to think about such things as walking to the bus stop as exercise? The ever-mindful Langer does not dismiss the possibility, but she emphasizes that the Boston hotel maids went through a true conversion from ignorance to belief. There is no doubt that placebos work, but the belief in their power must be complete.