Archive for November 29th, 2011

November 29, 2011

the HAES files: the placebo effect: belief and biology – part I

by Health At Every Size® Blog

by Jon Robison, PhD, MS

There was a flurry of activity on our list serve recently about a study that was actually published back in 2007 by Dr. Ellen Langer at Harvard University. Dr. Langer was interested in testing whether exercise-related health changes might be influenced by people’s “mind-set” (perception) about the amount of exercise in which they were engaging. To examine this, Dr. Langer picked a group of individuals who actually engage in more than enough daily exercise to satisfy recommendations for good health – women whose job it is to clean hotel rooms (room attendants).

The experiment included 84 room attendants from 7 different hotels who were randomly assigned to one of two conditions. Subjects in both conditions received written materials describing the benefits of exercise, including that exercise did not have to be difficult or intense to be beneficial. They were also given specific information about how many calories they were expending in the various activities of their daily work. In the informed condition only, the subjects were also shown how that amount of activity more than met current recommendations for a healthy lifestyle.  Interestingly, regardless of this reality, when surveyed 67% of the subjects had reported not exercising regularly and 37% had reported not getting any exercise at all.  At the beginning of the experiment and again 4 weeks later, physiological parameters (Blood pressure, BMI, W/H ratio, weight and body fat ) were collected and all subjects were told that the information would be used in the study to help them improve their health.

Here is a summary of the physiological changes that occurred after 4 weeks:

1) The informed group demonstrated significantly reduced systolic (- 10 points) and diastolic (-4 points) blood pressure

2) The informed groups’ BMI, weight, body fat and waist-to-hip-ratio all decreased

3) The percentage of subjects in the informed group who reported exercising regularly doubled from 39% to 79 %.

4) There were no significant changes in any variables in the control group

Subjects self-reported diet, activity (off the job) and substance use (caffeine, alcohol, cigarettes) indicated no changes in either group over the 4-week period. Subjects in the informed group reported getting significantly more exercise on the job although their workload during this period did not change. The researchers concluded that the observed physiological changes in the informed group were likely a result of the subjects increased perceived exercise.

As you might guess, the media had a field day with this, suggesting that it might be possible to “sit around on the couch and eat chocolate bonbons while genuinely believing that you are getting a lot of rigorous exercise.” At the same time some medical experts stated conclusively that people’s “mindsets” or perceptions can only influence “subjective types of findings” and not physiological parameters.

What is being tested here is a phenomenon called the placebo effect. We are probably most familiar with placebos through their use in studies by pharmaceutical companies testing new drugs.  A placebo is defined as:

a treatment or aspect of a treatment that does not have a specific action on a patient’s symptom or disease;  an inactive substance, a procedure with no therapeutic value.

 In other words, placebos are useless substances or procedures. Ironically, in study after study after study, across a broad range of medical conditions, 25-35% of patients consistently experience satisfactory relief when these useless substances and procedures are used for a broad range of medical conditions!  In fact, drug companies will not even consider marketing new drugs unless they outperform this placebo effect.

 The research on the power of placebos is extensive and convincing, sometimes even bordering on amazing.  Just a few examples; placebos have been shown to:

  • Increase lung capacity in children with asthma:  Children with asthma who were given a drug and told it would improve their breathing experienced measurable increased lung capacity, even though the drug was a placebo.
  • Provide pain relief equal to that of real knee surgery:  Adults undergoing surgery for knee pain experienced the same relief when they were told they had received the surgery, but in fact only a “sham” surgery had been done.
  • Regulate heart rate in people with neurocardiogenic syncope: Pacemakers implanted in the chest were effective for regulating dangerous heart rate abnormalities in people with this disorder whether the devices were turned on or not.
  • Cure nausea and vomiting:Pregnant women were cured of their nausea and vomiting when told the substance they were being given was a powerful antiemetic even though it (Ipecac) is normally used to induce vomiting.

 Six decades of research all leads to the same conclusion. What we think and believe can significantly influence what goes on in our body. A very recent study from 2010 reinforces the power of this connection between our belief and our biology. The study involved two groups of patients with Irritable Bowel Syndrome (IBS). One group received open-label placebo pills and was told these were “placebo pills made of an inert substance, like sugar pills that have been shown in clinical studies to produce significant improvement in IBS symptoms though mind-body, self healing processes.” The other group acted as a no-treatment control. The open-label placebo group actually did significantly better than the control group even though they were taking a placebo and they knew it.

What is going on here? Can placebos actually have this kind of impact on our physiology? If so, do we have any idea how this might happen? How does any of this relate to the findings of Langer’s study and issues of weight and health in general? Please check back for Part II to find out!

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