With each issue, Trib+Health brings you an interview with experts on issues related to health care. Here is this week's subject:
Mark Benden is an associate professor at Texas A&M University, where he is the head of the Environmental and Occupational Health Department of Public Health, and the director of the Ergonomics Center. He is also the primary investigator for a recent study published in the American Journal of Public Health, which examined the effects of standing desks in the classroom on children’s body mass index, or BMI.
Editor's note: This interview has been edited for length and clarity.
Trib+Health: What public health problem were you addressing with this study?
Mark Benden: We started into this research leaving years of work with adults and sedentary behavior, and branching out into this area with children because of the pandemic of childhood obesity. It’s a global problem; it’s worst in the western developed countries, but unfortunately, it’s spreading to developing nations.
It’s a significant health issue for cardiovascular disease, type 2 diabetes and life expectancy. And if you don’t nip it in the bud, especially with children, by about age 13, if they’re already obese, there’s about an 85 percent chance that will continue to adulthood.
Trib+Health: How did you carry out this study?
Benden: We were focused on the health implications of childhood obesity, and how changing the classroom environment with standing desks could affect that. We also looked at the positive effects of standing desks on behavioral engagement in classroom, which we’ve already published. Which was fantastic, and important to test out, because you want to ensure that any alterations to the classroom environment don’t harm the child’s academic enrichment.
During the process, every semester for the two years, all the kids wore activity monitors. These are very sophisticated, Fitbit-type devices. They’re wearable, on the arm, and they take heart rate, room temperature, fluctuations in the wearer’s temperature, while also monitoring activity levels. From even just the first year of school, we could see that the children in the activity permissive environments were moving more.
Trib+Health: Could you explain what an activity permissive environment is?
Benden: So the easiest way to understand it is to first understand what you’re working against. And you’re working against a lot of history in our western culture of this ‘sit down, sit still, be quiet’ approach to educating children.
It’s not about trading any kind of sitting behavior for standing. What we’re trying to do is trade static sitting behavior for movement, whole body ambulatory movement. We want kids up and moving, dancing, wiggling, shaking, leaning on the desk, putting one foot up on the foot rail. So we want a lot of different postures. Your best working position, or learning position, is your next one. Our bodies are made to move.
Trib+Health: How did these standing desks affect the children’s BMI?
Benden: The BMI itself in kids is done as a percentile, because it is gender and age related.
For adults, we just do a number based on your height-to-weight ratio. And we put you into a category: normal, overweight, obese. For children, we do that with percentiles. Normal would be less than the 85th percentile, overweight would be 85th to 95th, and obese would be over 95th for their age and gender.
We were looking at that BMI percentile number, because that’s a more accurate reflection of the exact child we are studying. Looking at that BMI percentile, the kids that were in the standing desk classrooms had a 5% difference over two years in their BMI percentile change. I’m saying change, because all children’s BMI’s should be going up. They should be increasing. They’re getting bigger, taller and heavier. It’s a normal part of growth.
What we were hoping was that we could alter the trajectory they’re on. Because that’s sort of the lifelong game — public health is all about prevention. So, how do you keep people from ending up at age 60, in the obese or morbidly obese category? One of the ways you do that is to prevent them from becoming obese by 13 or 18.
Trib+Health: What kind of future research would you like to see?
Benden: Well, the Framingham cardiovascular study is a good example. It has a lot of information about people over many, many years; including what they’ve done, what they’ve eaten, and how they’ve acted, whether they are smokers/non-smokers, marriage status, all those things, and then their cardiovascular outcomes. So you can start to see these clear trends; it’s one of the largest cardiovascular cohorts ever done.
I’d love to see that type of thing with this research. So, say today, in 2016, we started monitoring and tracking kids for sedentary behavior, movement, and activity. And we see if the kids that we were able to build in a little more movement and activity, what were their long-term health outcomes? That’s the kind of study we need. I think we’re at the point, now, that this type of data suggests we should do that kind of cohort study. I think that’s the next step.
Trib+Health: What’s the main takeaway for our readers?
Benden: I think the biggest thing to takeaway for all adults and children is twofold. Your best position to work or go to school in is your next one. And, ‘Sit less, move more.’