JACOB MEYER: Yes. This study comes from a large randomized controlled trial evaluating the effectiveness of mindfulness-based stress reduction training, or MBSR training. The program we used was designed around reducing stress. It was developed at the University of Massachusetts by Jon Kabat-Zinn, and was the first widely-used mindfulness program in the United States.
It had a variety of outcomes, but one involved participants split between; getting MBSR for eight weeks; participating in a matched aerobic exercise training group for eight weeks; or in a control group. We had people wear accelerometers for a week before being randomized into the groups, then ran the interventions, and then they wore the accelerometers for a week afterward to see if their physical activity changed. We wanted to find whether people were being more active, less active or about the same before and after.
What did you discover in the study?
This was done in fall to winter, and we saw that the control group decreased their physical activity by a pretty large amount whereas both the exercise and the meditation group maintained or slightly increased their activity over those two months.
Did these results surprise you?
Totally. These were not what I expected. I thought that the meditation group might provide some benefit compared to the control group, but I didn’t expect it to provide the benefit that it did – comparable to the aerobic exercise.
I also thought that we were going to see participants in the meditation group end up being more sedentary or having more time seated during the day, and that wasn’t the case. Instead we saw no shift towards being more sedentary, and much more activity than I had expected.
How might this help promote physical activity?
We’re really just trying to figure out why this happened, when we didn’t think it was going to. The usual way of thinking about exercise is we have someone come in and work out with a trainer in the gym, and that’s going to lead them to being more active afterwards and to all these health benefits. These results made us take a step back and think: can we get someone to become a little bit more mindful, a little bit more present and aware in what they are doing? Might that increased mindfulness end up leading that person to make choices that include more physical activity in their life? And might that be as effective in increasing someone’s physical activity as what we normally have them do, which is come into a gym?
I’m just still amazed by the fact that the meditation group had similar effects on physical activity as the aerobic exercise training group. As a kinesiologist, considering what we think about and the way we prescribe exercise, this is totally not what I would have expected.
What were some of the participants’ thoughts about their behavior?
We had people record what they thought their physical activity was over the last week both before and after the intervention. The meditation group reported similar levels of physical activity before and after the intervention, and largely that’s what happened when we actually had them wear the accelerometers. But the exercise group said they did substantially more activity. When we looked at the accelerometers they did only a little bit more.
What I took from that was that the meditation group was more accurate in their representation of how they were active.
So the ones trained in mindfulness were more aware of their bodies and their activity?
They were able to say “I don’t think I’ve changed my activity”, and that was the case. Whereas the exercise group didn’t change their activity but they said that they increased it substantially. The control group said they didn’t think they changed their activity and they actually decreased by a good amount. The meditation group was the only group that matched in terms of what they thought they did and what we saw from the physical activity monitors.
However, there were only 49 people split across the three groups. There were 14-18 per group in the end and we would really need to see this replicated in a larger trial to know if these are true effects of these interventions.
So it is clear that mindfulness has an effect on physical activity, but what about the effects of physical activity on the mind? You’ve been involved in an analysis of clinical trials on strength training to see whether that has the same effect as running and aerobic training. Can you tell us about that?
There has been a lot of information about how aerobic exercise such as running influences the body, but there has been a whole lot less that looks at resistance exercise training. This study tried to figure out: is resistance training giving us the same effect as we see from aerobic exercise training? Or is it giving us something different? What we saw is it’s about the same in terms of general effects.
The strength training was associated with a moderate reduction in symptoms of depression, which is about the same effect as we would see from aerobic exercise training, from antidepressant medications, or from psychotherapy.