01:28pm Monday 23 September 2019

Physical Activity’s “Great Challenge”

Andrew Rundle, PhD, knows this as much as anyone. This past spring, he took his passion for the subject to the TEDMED conference in Washington, DC, where he took part in the Robert Wood Johnson Foundation-sponsored Great Challenges program, which aims to call attention to, and start conversations about, major health and medical issues. Dr. Rundle’s issue—physical activity—was chosen from a field of 50 to be part of a select group of 20 “great challenges.”

Now, he and a team of experts are soliciting questions and ideas on the TEDMED website (click here to make your voice heard). These will serve as a springboard for a series of Q&As on Twitter leading up to a presentation at next year’s TEDMED. Below, Dr. Rundle answers questions about physical activity and shares his preference for staying on his feet during work hours and what research says about how where you live may make the difference for your health. 

Describe your TEDMED challenge. What’s your pitch? 

Physical activity prevents breast and colon cancer, hypertension, Type 2 diabetes, obesity and death from cardiovascular disease, but less than 20% of Americans meet current recommendations for physical activity.  

So physical activity is more than just a slimmer waistband? 

It is actually fairly complicated, for some diseases it appears the benefits of physical activity accrue through preventing obesity and lowering body weight. But for colon and breast cancer the protective effects of physical activity are not related to differences in weight between more and less active people. It seems that regardless of your weight, higher levels of physical activity are protective against these cancers. In fact, both lower weight and higher physical activity independently protect against colon and breast cancer. However, we don’t really know what the biochemical mechanisms are through which physical activity prevents cancer.

The New York Times recently reported on a couple of studies showing some alarming things about physical inactivity, specifically sitting, as measured through TV watching. It seems that more time sitting translates to a shorter and less robust life, perhaps even if we exercise. What do you make of this?

Yes, these were some interesting findings. It appears that large amounts of sedentary behavior, such as sitting or reclining, are bad for your health, even if you also engage in exercise or regular physical activity. It appears to be important to keep your muscles working as much of the day as possible. Because of this I try to spend time standing in my office; standing consumes 20% more energy than sitting. Also during a meeting I’ll sometimes force my colleagues to take a walk with me, to get a coffee or whatever. And lastly, I’ll take the stairs rather than take the elevator. 

Was there a time in your life when you were less attentive to these things? What got you on your feet?

I’ve been studying physical activity and health for the past decade, and the work has really inspired me to pursue a more active lifestyle. But in the late 90s I was pretty sedentary and was 30 pounds heavier than I am now. These days I go to the gym before work and get off the subway or bus a stop earlier than I need to so that I have to walk a ways. 

Is there an evolutionary aspect to this? Did humans evolve to be more active? 

There is quite a bit of debate about this. It is not really clear how active our ancestors were over the course of evolution. It is possible that our hunter-gatherer forefathers were relatively sedentary, but had bursts of activity during hunting.  

As part of this TEDMED Challenge, you’re looking for ideas on how to promote physical activity. What are some good ideas you’ve heard? 

We have just started collecting ideas from the TEDMED community, so we are still looking to see what comes in to the website. My own work focuses on how we can use urban design to promote physical activity through increasing active transport, which is walking and cycling, and also to promote recreational activity by understanding what sort of park spaces people use for physical activity. The idea is that we can design the spaces we live in so that physical activity does not have to be a planned event, but rather is a default state that is part of everyday living.

There are walking and running advocates on your team. I’m a big fan of both these activities, and I’m lucky enough to live in NYC where it’s easy to do them. I also don’t have a car. 

Our research has been showing that neighborhood walkability can be quite important for promoting physical activity and higher walkability is associated with lower body mass index. Walkability is an idea that comes out of the urban design and planning literature and is a set of built environment characteristics that support pedestrian activity. Walkable neighborhoods are characterized by higher population density, mixing of residential, commercial, recreational, and institutional land uses, more gridded street designs that have few dead-ends or cul-de-sacs, and access to public transportation. While access to public transportation sounds like it might reduce walking, it actually frees you from car dependence and increases your total pedestrian activity. If you think about it, my commute to work by subway requires me to walk several blocks and to climb four flights of stairs: that’s just to get to work. In fact, transit users spend a median of 19 minutes just walking to and from the transit stop.

Mailman School of Public Health

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