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Exercise doesn’t help depression? Let’s take a real look at that study.

The views expressed are those of the author and are not necessarily those of Scientific American.


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When I first saw the coverage of the article appear on Jezebel saying that exercise doesn’t help depression, I didn’t believe it. I read the press release, and really didn’t believe it. And then, I read the article.

Do I believe the article? Yes, I believe that the data are as they say they are. But do I believe that exercise doesn’t help depression? Nope. Not a chance. Because that’s not what this study says. And in a truly massive failure” of press release and media coverage (some of which was elegantly skewered by Martin Robbins and Tom Chivers), everyone is going to get the wrong idea.


(Source)

Chalder et al. “Facilitated physical activity as a treatment for depressed adults: randomised controlled trial” British Medical Journal, 2012.

Contrary to some of the statements in the introduction of the paper, there are several meta-analyses which support the effects of exercise in treating symptoms of depression. However, they authors are right, many of the studies have small numbers of people and have extensive exercise interventions. The authors of this study were interested in a milder intervention in a larger group of people: could moderate increases in physical activity buttress depression treatment?

To look at this, they recruited around 360 people who were experiencing a new episode of depression. They assigned half of them to an exercise intervention, and half to control. ALL of them got “normal” treatment, meaning some additionally got talk therapy, some additionally got antidepressants of various types, etc. In the exercise intervention, the group received three meetings with a trained facilitator and 10 phone calls during the year, encouraging them to exercise for 150 minutes per week of moderate to vigorous physical activity in bouts of at least 10 minutes.

The findings showed no effect on depression score as a function of whether the people were assigned to the exercise arm or not. Most people improved in their measures of depression, but there was no difference between the groups.

So…at first blush, it looks like exercise doesn’t help depression. But it’s really not that simple.

Here’s the most important issue: the people in the physical activity intervention did not end up exercising more than controls. The effect was p=0.08 (statistical significance is p<0.05), and the effect was only significant when all three time interventions were considered together. For example, at 4 months from the start of the study, 52% of the physical activity groups were achieving 150 min of moderate to vigorous exercise per day (that's walking and up), compared to 43% of the control arm. The data was self-reported, and the authors also noted that the self-reports didn't line up well with the accelerometry measures designed to measure the physical activity, so it's very possible that even those who reported exercising were not working out as much as they thought they were (not only that, if you're talking to a physical activity facilitator and you know full well the study wants you to exercise, you might talk up your moderate exercise more than you might otherwise).

With adherence like that, no wonder they didn't get an effect. They described good adherence to the study parameters. This means that the people in the exercise arm attended the meetings and phone calls that they were supposed to, but it sure as heck doesn’t mean they exercised more. Not only that, I don’t think this was the right intervention to really look at. The exercise stuff was designed to fit in your normal day. Walking to your car counts, taking the stairs counts, etc. That’s…not an exercise program that can really give you a sense of achievement. In essence, this study asked for the bare minimum of healthy physical activity. Not only that, the study did not discount those who did not exercise, up to 58% of the exercise arm.

What would they have gotten if they had just compared those who exercised against those who didn’t regardless of the arm of their experiment? What if they’d looked at depression score as a function of exercise amount? Surely not all of these people were moderate walkers, some must have been more or less athletic than others, did they show differences?

There’s another issue as well: most of the patients, but not all, were being treated with antidepressants. It’s yet another variable and one they could have, and should have, separated out for analysis. They looked for decreases in antidepressant use in the control and exercise arms (and found no difference), but they did not look for differences in adherence or depression scores in those treated with antidepressants vs not.

In sum, this study did not assess whether exercise helps symptoms of depression. What it assessed was whether someone encouraging you to exercise helped your feelings of depression, regardless of whether you exercised or not.

Is it a well-designed study? Yes, for what it is. Was it well-performed? Not really. Is it well-analyzed? I don’t really think so. And was it well reported, in the press release and on? Definitely not. And I’m not the only one who thinks so, the responses of various professionals on the BMJ site itself have pointed out similar flaws.

The fact is, this study does not show that exercise has no effect on depression. It shows that this specific intervention, having someone encourage you to exercise, does not help depression. Not only that, it only shows that having someone encourage you to exercise doesn’t help depression scores on top of normal antidepressant treatment. But that sounds a lot less surprising and interesting, now doesn’t it.

What we need here is a better study. We need a trial where some receive therapy, some receive antidepressants, some receive exercise (and I’m talking someone being with you when you work out and meeting specific exercise goals that are readily measured and defined), and some receive combinations of these interventions. Then we’ll have something that I believe. This study? This doesn’t fit the bill.

Chalder, M., Wiles, N., Campbell, J., Hollinghurst, S., Haase, A., Taylor, A., Fox, K., Costelloe, C., Searle, A., Baxter, H., Winder, R., Wright, C., Turner, K., Calnan, M., Lawlor, D., Peters, T., Sharp, D., Montgomery, A., & Lewis, G. (2012). Facilitated physical activity as a treatment for depressed adults: randomised controlled trial BMJ, 344 (jun06 1) DOI: 10.1136/bmj.e2758

Scicurious About the Author: Scicurious is a PhD in Physiology, and is currently a postdoc in biomedical research. She loves the brain. And so should you. Follow on Twitter @Scicurious.

The views expressed are those of the author and are not necessarily those of Scientific American.





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  1. 1. JDahiya 4:04 am 06/11/2012

    Oh, wow, now that you explain it, it’s a piece of no-news.

    Link to this
  2. 2. dijon9054 8:45 am 06/11/2012

    I took up running to ease my depression and it helped enormously, in so many ways. Saying exercise doesn’t help depression seems slightly odd when so many people besides myself have experienced the benefits of it.

    http://understanding-depression-symptoms.com

    Link to this
  3. 3. TLHart 9:42 am 06/11/2012

    Anecdotes aren’t evidence, but they could provide inspiration for further research – so, my experience with depression is that I was able to exercise more as my depression lifted. Exercise does nothing to impact my symptoms, but managing the symptoms gives me enough energy to take care of my physical needs.

    Link to this
  4. 4. sciliz 10:02 am 06/11/2012

    What are you talking about?? THIS IS AN INCREDIBLY IMPORTANT STUDY!!!!!11!!!

    Obviously, you have never been depressed and surrounded by hipster running douchecanoes who like to tell you how much better you’d feel if you just ran. Now we have data that PROVES their approach DOES NOT WORK.

    If hearing “this helped me, so it should help you” doesn’t fill you with Rage and Frustration (directed at the person saying it, or at yourself), you are Not Really Very Depressed. Anyone who doesn’t understand that “this helped me, so it should help you” is a terrible thing to say to a depressed person (and really, kind of a douchey thing to say to anyone) suffers from an empathy chasm so enormous they really shouldn’t talk to anyone.

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  5. 5. Andreas Johansson 10:09 am 06/11/2012

    sciliz wrote:
    Obviously, you have never been depressed and surrounded by hipster running douchecanoes who like to tell you how much better you’d feel if you just ran. Now we have data that PROVES their approach DOES NOT WORK.

    I have, and this study doesn’t prove anything of the sort.

    (And no, I didn’t take up running. I eventually got better, but I still don’t run.)

    Link to this
  6. 6. scicurious 10:13 am 06/11/2012

    @sciliz: I never said that exercise alone definitely works. I certainly don’t think it would work for everyone, and I don’t think it’s a magic bullet for depression. But I know there are studies out there showing it can help in some patients. Hyping this study to show that exercise does not help is a big misservice and misinformation, when this study does not show anything of the kind.

    However, if what you mean is that ENCOURAGEMENT to exercise doesn’t help depression (like when running people tell you you should), then, yup, I entirely agree with you, it doesn’t. :)

    Link to this
  7. 7. sciliz 11:47 am 06/11/2012

    *sigh* in all seriousness (you guys take all the fun out of rants!)… Sci, I think you did a great job pointing out the flaws in the paper and I really appreciate it. I’d seen the headline but hadn’t looked up the paper.
    Personally, I’m actually pretty well “sold” on the benefits of exercising, including cognitive/emotional benefits (though for what it’s worth, I was more persuaded by the literature on Parkinson’s and BDNF than the literature on depression per se). Still, I wonder if a pretty significant subset of medication treatment-resistant depression are essentially neurons that can’t grow well (don’t know if it’s that you can’t get the BDNF et al. up or if they don’t respond to it as well, or if there are people that fall into both categories. Probably the later). I don’t know that exercise would help those people.

    So I think we agree- if the headline had been about “encouraging people to exercise doesn’t help them”, that would have been much more accurate (and productive).

    Link to this
  8. 8. scicurious 12:54 pm 06/11/2012

    @sciliz: Oops! I figured you were kidding with all the 1′s in your !!, but I wasn’t sure…But yes, I would say that a bunch of runners being all “YOU SHOULD EXERCISE RUN MARATHONS RAH” at someone who is depressed is probably NOT going to have beneficial effects on symptomatology. :)

    I admit, as a runner, we can be more than a bit evangelical in our cause. :)

    Link to this
  9. 9. george19 3:07 pm 06/11/2012

    This study was badly done and proves nothing.

    Link to this
  10. 10. gmperkins 3:50 pm 06/11/2012

    @george19 Well, I think it shows that if you want exercise to help someone with depression, you have to do a bit more than a few training sessions and some phone calls. (unless they are self-motivated but then they probably would not be depressed)
    Which brings up a problem since if you have patients attending P.E. or P.T or have a coach stop by their homes some number of days a week, you run into the issue of “is it exercise or is it the social interaction with someone who is trying to help you get over your depression? (or both)”. So you need a ‘coached group’, a group where someone shows up like a coach or the same amount of time but is there to talk and help and a control group. Not the easiest of studies to pull off due to funding.

    Link to this
  11. 11. gmperkins 3:52 pm 06/11/2012

    Hmmm, why is there no edit function and why is this editor so poor?(especially at a scientific magazine’s website, heh).

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  12. 12. tolson 4:07 pm 06/11/2012

    This article does not contain Any reliable information. Who, or what can possibly decipher one form of depression, vs. another? In my case, I sustained a traumatic brain injury at the age of 17. I was in a wheelchair for 8 years. Exercise was the only way that I was able to release my emotions. I am now 13 years & going strong. And, I accredit exercise for a large portion of my survival!

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  13. 13. bmw007wu 4:59 pm 06/11/2012

    I was astonished last week when I read the way news outlets were interpreting the results of this study. Thank you for writing this. I hope, but doubt, that your perspective will receive equal media coverage.

    Link to this
  14. 14. Flotsam 7:09 pm 06/11/2012

    Lots of anecdotes and people attached to a specific conclusion in this article and comment thread, imo.

    Link to this
  15. 15. flipty651 3:10 pm 06/12/2012

    Do you know what else doesn’t help people that are experiencing depression? Telling them that something that is practically universally accepted, even if it’s not 100.00000% “scientifically accurate” (and what is?), won’t help them.

    Guess what the response to that is by everyone so far I’ve encountered so far with depression will likely be? “I KNEW IT. GOOD THING I WASN’T DOING IT.” or “SEE? I TOLD YOU IT WASN’T DOING ANYTHING!”

    Also my experience with depression is that having someone tell you what to do isn’t enough, especially if it’s something you don’t want to do (for instance, vigorous exercise).

    I understand that depression is a real illness. Hell, I’ve got it myself. But exercise does help me, and it helps so many others there’s no way it’s not legit . It’s not medicine.

    Link to this
  16. 16. rruusu 9:57 am 06/13/2012

    “It shows that this specific intervention, having someone encourage you to exercise, does not help depression.”

    No, it doesn’t. It shows that it doesn’t help a lot, i.e., it shows that the effect is too small to be reliably measured with the given sample size. No evidence of effect is *not* equal to evidence of no effect.

    Link to this
  17. 17. rruusu 10:09 am 06/13/2012

    Studying the effect of exercise on depression is especially hard, as an increase in exercise is caused by an easing depression. The causality relationship is most probably bidirectional. This in itself makes it an important factor, as it is a self-reinforcing cycle. Thus, it is quite understandable that mere encouragement doesn’t help a lot. A more vigorous intervention is needed to break the cycle.

    Link to this
  18. 18. Diesel67 2:41 pm 06/15/2012

    Jezebel was the evil queen who tried to seduce us away from God to idol worship. Anything coming from a Jezebel must be viewed with a jaundiced eye :)

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  19. 19. ait10101 7:05 pm 06/15/2012

    I find that forcing myself to walk around the neighbourhood or swimming with friends often helps, but I suspect that it is just getting out and doing something rather than lying in bed and fiddling on the internet, or reading magazines at home. I take an SSRI, have been for many years. They help, as I discover when I stop taking them (taper off). Talk therapy was fun, but never really helped me. There are so many variables, and people respond differently. Cause and effect are hard to pin down even otherwise well designed studies because it is a complex rather than linear system. Controlling for all factors but the tested factor not only ignores synergies, but is subject to the law of unintended consequences. I have been studying the foundations of the logic of complex systems and causality for some thirty years now, and have collaborated with scientists in ecology, evolution, development and social systems from a systems theory perspective using an approach involving distributed causation in reorganising networks. Depression is definitely in this class, in my opinion, but I have never tested that guess using my own methods. A little bit to close to home, perhaps, and I worry about my objectivity here.

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  20. 20. scicurious 8:44 pm 06/17/2012

    @babyfacemagee: if you wonder where your comment has gone, it’s gone to spam, because you’re insulting someone for no reason and being rather awful.

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  21. 21. Raghuvanshi1 12:20 pm 06/26/2012

    Exercise is a terrific outlet for anxiety.This my experiences.Simple reason behind this secrete is when we are depressed at that time supply of oxygen diminished in the brain.At that moment if we start fast walking naturally supply of oxygen increased and automatically depression finished.

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  22. 22. EvertVd 7:53 am 11/12/2012

    I can only talk from my own experience. As a lifelong sufferer from depressions and anxiety (real fear) attacks, I tried everything to relieve my symptoms, including exercise. My personal experience with this is that at some point (either during or afterwards) I get a feeling which I can only compare to some sort of melancholy, which slowly turns into anxiety and ultimately in either fear or depression. I tried it more than once and over longer periods of time since some people suggested it was a phase I needed to go through. but after 2 years of regular exercise those symptoms did not go away. So I am very sceptical when it comes to the statement that exercise is good against depression. At the very least it probably depends on the person.

    Link to this
  23. 23. SarahGoodwich 1:51 am 01/30/2013

    This doesn’t disprove the claim that “exercise doesn’t help depression,” when in ra simply doesn’t ESTABLISH that exercise DOES help depression.

    Claims that “exercise helps depression” are a popular rash of Secondary Victimization, by blaming depressed people as “just being lazy” and pushing them into the gym and out onto roadwork, regardless of the neutral or negative consequences- as well as the irresponsibility of presenting false hope.
    (Unfortunately, the PSY-community excels at hand-washing and ass-covering, even during inhumane forced treatment including sterilization, shock-treatments and frontal lobotomy.)

    This myth that “exercise helps depression” is hardly new: the “Deadly Sin” of “Sloth” likewise blames those who are depressed, or “poor in spirit,” for their plight; which of course creates a vicious cycle of victim-blaming and resultant persecution.
    (Similarly, obesity was blamed on the Deadly Sin of “Gluttony,” presenting it as a “safe prejudice” to oppress those with childhood Diabetes, eating-disorders or other illnesses as chosen character-defects, against all logic; this is likewise comorbid with depression, resulting in an overweight victim of depression being labeled as a “lazy glutton,” regardless of the facts).

    Similar platitudes include “busy hands are happy hands,” and likewise blaming depressed people as guilty of self-pity, parasitism, “goldbricking” etc. as physicians in pre-psychology eras would simply claim all untreatable illnesses simply must be intentional ruses, in a rash of archaic medieval stigma against mental illness.

    I’ve even known unfit parents who even told their kids “go out and run, you’ll feel better” in order to blame the effects of the toxic home-environment, abuse and neglect on the child own choices, failures and defects.

    In all, this is a common Catch-22 to ultimately blame the victim further– which is a popular scapegoat and cop-out to deflect any responsibility by indulging conceit.

    I don’t need to explain the ethical dilemma which is worse than Social Darwinism, blaming the victims choices rather than their genes.

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  24. 24. scicurious 1:00 pm 02/3/2013

    Sarah: thank you for your comment. I understand where you are coming from, but I really do not think that the current research on exercise and depression is victim blaming. Those of us who do depression research are very aware that it is nothing to do with laziness. But some studies have found that exercise can help increase feelings of well-being and life satisfaction, as I mention in the post above. This is not to say that people with depression are lazy and do not exercise, as many of them do, it merely says that some studies suggest that increasing exercise would help relieve the symptoms. Other studies in animals have looked at the neurobiological reasons why this might be the case as well. So it’s not victim-blaming, it’s really trying to help, and I am very sorry if I came across any other way.

    Link to this

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