The Q&A: Ranjana Mehta

With each issue, Trib+Health brings you an interview with experts on issues related to health care. Here is this week's subject:

Ranjana Mehta is an assistant professor in the department of environmental and occupational health at Texas A&M University. She is the director of the neuroergonomics lab and co-director of the Texas A&M ergonomics center in the School of Public Health. Mehta researched the effects that standing desks have on high school students.

Editor's note: This interview has been edited for length and clarity.

Trib+Health: What kind of effects did the standing desks have on students in your study?

Ranjana Mehta: This has been an ongoing effort by the P.I., the principal investigator, Dr. Mark Bendon, who’s actually the director of the ergonomics center. ...

Much of the work in the past has been on understanding how standing desks improve physical activity or reduce sedentariness, improve calorie expenditure. A lot of work they did with this focus in mind.

Through anecdotal evidence, teachers reported back, saying, “You know what, my students who were assigned the standing desks seem to be more alert and seem to be more engaged in the classroom.” … That’s when he approached me with the idea that it is possible to look at their cognitive health.

So what I did was I took the traditional approaches that exercise does. In any school-based exercise intervention, we know that exercise improves cognition, and exercise improves brain health. There’s tons of evidence around it in both school-based interventions and in the working population and general population. So we basically used the same approach.

My conceptual model for this was if students are standing more, they are clearly being more active and are somehow having greater energy expenditure than what they would be if they had traditional desks.

So what we did (was) we looked at high school students. There was one school we studied. There were 450 students equipped with standing desks. We only looked at a handful of those students, and we tested them when they were equipped with the standing desks and then next semester after 20 to 30 weeks of standing desk exposure.

We tested them on basic cognitive skills. We chose certain skills that we know through scientific studies and evidence are shown to mature by the age of 12. These particular cognitive skills would not have been enhanced by them progressing through the semester with school because these are basic skills.

Trib+Health: Why did you research freshman students over a younger or older group?

Mehta: First of all, this was an exploration study. We wanted to look at high school freshmen, one of the reasons being this was a CDC grant and we only had one school in mind. Just to be very clear, these are preliminary results. ...

The reason we did this is because we only had one high school in mind that we could look at in our study given the budgetary constraint. ... We focused on high school students because we knew by the ages of 14 and 15, what we were testing would have already matured.

Dr. Bendon had already tested physical activity levels in children and then with high school students. He wanted to see whether he saw similar improvements in physical activity. I basically came in during that phase.

Trib+Health: Why is it significant that the use of standing desks improved neurocognitive functions in these students?

Mehta: As I said before, the proposed mechanism that we think is impacting this is that by standing, we are increasing their activity levels.

When you’re talking about standing, we don’t really mean standing in one place. They’re actually moving more, and in doing so they’re getting a lot more exercise than sitting down.

It’s my theory that it has to do with this increasing activity that we are (seeing) from them over a couple of weeks that is helping them facilitate this improvement in cognition.

Now, again, this needs to be tested in detail. We would love to do structural imaging of the brain to see if brain structure gets better, but, of course, we need to (do) these in small manageable steps.

Trib+Health: It sounds like you plan to continue researching, right?

Mehta: Oh yes! This is just the beginning.

We are at the point of testing things in the lab. We have tested things in the school, and now we want to take them to multiple schools with a larger sample size with a lot of different exposures.

We really want to see what is the threshold, if we can even get to that point where we say 10 weeks of exposure is improving versus needing 30 weeks of exposure, or a longer time.

A lot of work needs to be done, but these are preliminary, exciting findings that we were anticipating in the first place.

Trib+Health: Should schools start exploring options to change their classroom environments so students can focus and behave better, perhaps by adopting standing desks?

Mehta: That would be the long-term goal, to provide evidence-based guidelines as to not only are standing desks reducing sedentary behavior in your children because they spend all or part of their time in schools sitting. It can also improve cognition.

The whole premise behind this is that exercise should never be replaced by anything. We’re not saying that we want to replace exercise interventions. Exercise is the most important.

Our initial evidence is also saying that this is improving their engagement. It is also improving their cognition. But we definitely need to try this out on a larger scale before we can even begin to provide those recommendations. We are working towards that.

Trib+Health: What drew you into the study?

Mehta: To me, it is a no brainer if there’s an intervention that not only helps gets closer to addressing childhood obesity but also improve their learning abilities then I would like to test that to see if there’s hard evidence that directs us to saying, “This is a good intervention.” That’s what got me interested in this.

Trib+Health: Do you use a standing desk?

Mehta: Of course. To be really frank, when I first started in the school, half of the desks were standing desks. We do practice what we preach.

I used to drive from Houston to College Station every day. It used to be an hour and 45 minute drive and I would be in my little Civic, my little graduate school car I had. As soon as I got to school, there’s my chair again and I would sit down again. Within a month, I moved to standing desk.