While reading through one of the books I recommend at the end of the BS-Detection guide, (Bad Science by Ben Goldacre, seriously amazing read. If you enjoy my work at all you'll love this book) I came across an interesting study on placebos.
(He even made a note saying that if you had a possible explanation for the results of this study, that you should write a blog post. So...here we are!)
This is a good study to try and read into a little bit, even if you're not a statistician. We may not be able to decide if their statistical analysis is any good (considering my 'C' grade in high school statistics, I'm gonna go ahead and put myself in the 'not expert' category on that one), but most of the study is in language any lay-person can understand.
Can the placebo effect improve the benefits of exercise?
Let's go over the structure of this study real quick:
What is the study trying to show?
In the first few paragraphs of this study, below the bolded abstract, the authors give us some interesting background on the surprising effects of placebos. Their definition of 'the placebo effect' is:
The placebo effect is any effect that is not attributed to an actual pharmaceutical drug or remedy, but rather is attributed to the individual’s mind-set.
And that's a very accurate definition. Let's expand on that a bit with an entertaining example from the wonderfully crude TV show It's Always Sunny in Philadelphia.
In the episode "Manhunters," two of the main characters (Dee and Charlie) are persuaded by Dee's father, Frank, that they've accidentally eaten human flesh. Over the course of the episode, Dee and Charlie experience increasing cravings for human flesh, culminating in them kidnapping a homeless man to bring back to their apartment and eat.
Thankfully, Frank informs them in time that it was actually raccoon meat, and he was just fucking with them the whole time.
This example was just an excuse to post this youtube clip.
But Dee and Charlie feel the cravings for human flesh so intensely, they are convinced Frank is lying, and go on to attempt to eat him instead.
So, placebo effect is thinking you've eaten human flesh, causing the effect of craving human flesh, even though you only ate raccoon meat.
Where were we? Ah, right, so the researchers were trying to determine:
...the role of the placebo effect (the moderating role of mind-set) in the relationship between exercise and health. We hypothesized that the placebo effect plays a role in the health benefits of exercise: that one’s mind-set mediates the connection between exercise and one’s health.
In other words, does simply telling people about the benefits of their current exercise increase the benefits of said exercise without changing anything else about their lives?
How did they conduct the study?
Researchers took 84 maids from 7 different hotels. About half went into a 'control' group, and the other half were referred to as the 'informed' group.
The paper details exactly how they picked the maids and how they controlled for confounding factors like age, ethnicity, socioeconomic standing, etc. As well, they made sure that the maids from different groups didn't talk to eachother, to ensure the placebo effect didn't spread to the 'control' group.
A control group is standard in most all experiments. A control group basically exists as a reference for the changes made in the experiment group.
For instance, in this study, if we had no control group, we would have no way of knowing whether any changes that occurred in the experiment group had anything to do with the actual experiment changes, or changes in say, the weather, or any other natural fluctuations.
What were they measuring?
- How much exercise the women believed they got
- How much of their job they thought counted as 'exercise'
- Weight, body fat percentage (via one of these), and waist-to-hip ratio
- Blood Pressure
They measured the first two bullet points by just surveying the workers. This would give insight into how their mind-set changed over the course of the experiment. The second two bullet points showed actual objective data to see if those changes in mind-set actually affected their measurable health levels.
What were the differences between the 'informed' group and the 'experiment' group?
Both groups were educated on their daily recommended amount of exercise, based on the Surgeon General's recommendations; about 200 calories worth per day. They were given handouts and posters were put up in their work lounges to remind them.
However, the 'informed' group was told that their jobs more than fulfilled said recommendations. The 'control' group was not told this.
So basically, the only difference was that the informed group had the peace of mind and satisfaction of knowing that they were surpassing the amount of exercise recommended for them to obtain and maintain good health, while the control group did not.
What were the results?
Four weeks later, the informed group had:
- Much higher perceived amount of regular exercise
- Regarded their job as contributing much more towards their exercise
- Lower systolic (the first number in blood pressure readings) blood pressure by 10 points
- Lost an average of 2 pounds
- Lowered waist-to-hip ratio and body fat
These changes were not seen in the control group. In fact, they felt that their jobs counted less as exercise than before the experiment!
So can the placebo effect help me to lose weight?
Possibly. But don't get too excited about the results yet. First of all, the body fat and weight loss results could be erroneous. The scale they used to measure body fat is highly inaccurate and very susceptible to changes from water content in the body. As well, many people experience weight fluctuations of 2+ pounds on a day to day basis regularly.
However, it's harder to mess up a blood pressure reading. With an average decrease of 10 points, something was definitely going on to improve the health of the ladies in the informed group.
The researchers stated that it doesn't appear that the ladies in the study changed their dietary habits. Nor did they report exercising more. So, did being informed that they were doing exercise magically cause these improvements in health?
I think what's probably going on here is some combination and waterfall effect of:
- Realizing that they're not lazy people, and healthier than they thought
- Figuring that maybe they've got a little bit more of their shit together than they realized
- Perhaps having a little more fun with the job, potentially increasing their physical exertion without consciously registering it
- Decrease in stress
- Increase in duration and quality of sleep
- Decrease in caloric intake due to stress reduction and increase in sleep, as well as because they think of themselves as healthier, fitter people than before.
These changes wouldn't have been a conscious decision by the ladies, so they wouldn't have reported any changes in their habits.
It's a bit of a stretch, I admit. But it seems more likely than a simple change in mindset decreasing one's waist-to-hip ratio. Those kinds of direct physical changes don't seem to be in the realm of placebo, kind of like how placebo can't re-grow limbs or alleviate paralysis.
What's the take-home?
Realize that exercise is ANY KIND of physical exertion. If you work a physical job like walking dogs, construction, teaching, cleaning, whatever, then you are getting exercise. If you enjoy playing frisbee with your dog, you are getting exercise. Exercise does not have to happen in a gym or even as a conscious effort.
As well, recognize the awesome power of a positive mind-set. Trust me, I know that this is easier said than done. I have not in any way accomplished this yet in my own life. But just feeling like you're just a little more in control of your life, eliminating just one source of stress, or maybe thinking of yourself as a bit of a healthier person can have huge effects on your actions and motivations.
Interested in learning more about how awesome and interesting the placebo effect is? Pick up Bad Science by Ben Goldacre. Seriously. This book is amazing.