Walking, Working and Thinking

by Emily Oken, MD, MPH

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As I write this post, I am walking on my ‘TreadDesk’.  For those who might not have heard about such a thing, treadmill desks are slow treadmills that are designed to fit underneath a standing desk, to allow you to walk while you work.  Their recent surge in popularity is likely due to growing evidence that sedentary time, i.e. time spent sitting, is a strong predictor of higher risk for obesity, type 2 diabetes, cardiovascular disease, and premature mortality.  Interventions to improve physical activity via walking have been shown to result in improvements in a number of cardiovascular risk factors, including lower blood pressure, blood glucose, cholesterol, waist circumference, and body mass index (for example, see this recent study).

So, the cardiovascular benefits of more walking seem clear; but for many of us, the workday is mostly spent sitting.  Should we all be using treadmill desks? 

In a recent study, investigators at Brigham Young University had healthy young adults type and perform tests of attention, learning, and memory, while either slowly walking on a treadmill (set to 1.5 mph) or sitting.  The treadmill group performed significantly worse on all measures of typing, and on several of the cognitive tests, including tests of attention and learning.  This finding was not entirely unexpected.  Previous studies have found that a small but positive effect on cognition during and after a bout of exercise.  However, the results of tests that require accuracy or speed tend to be somewhat worse with exercise. 

These findings also come as little surprise to me.  My treadmill goes as fast as 4 miles per hour, though I find that I can’t really work on it if it is going faster than 2 mph.   I wouldn’t count the time I spend on it as vigorous physical activity.  However, it is definitely different than sitting – I am more alert.  My favorite time to use it is just after lunch, when I am feeling a little sleepy.  Since this type of fatigue after eating probably derives from a post-meal surge of insulin, using my treadmill is probably helping to reduce the amount of insulin my body requires to process the sugar in my lunch, maybe even reducing my diabetes risk.   I can do some things fairly easily while walking on my treadmill, like checking email, watching the numerous training videos required by my employer, or talking on the phone (but only while wearing a headset. If I try to hold the receiver I soon feel off balance).  I can’t, however, focus on anything that requires really deep concentration, like writing a paper or grant application.  Also, after a while, my knees start to get a little achy, and I get that dizzy feeling that comes from moving while also standing still. 

So now my blog post is written, and I’m 3500 steps closer to my daily goal.  It’s time to sit down and do some real work.