A treadmill desk Update and Re-evaluation

Published September 13, 2012; reformatted 9.21.2015
This is an update of this account published in April of this year. I continue to use my treadmill desk for most of the day. I had to establish distance/day limit, because I found that walking too much further than that resulted in sore feet at night. It is this limit and the need for it that has triggered this update, which during its composition and editing became a re-evaluation.

The pace at which I walk gradually increased over time. I have been walking at 2 miles per hour (mph), so if I work at the desk for 5 hours, that's 10 miles. I'm not always at my desk, so I don't always go a full 10 miles, but there are days when I am at my desk for eight hours plus, and it was on those days that I realized that I couldn't handle walking for the full time, at least not at 2 mph.

On days, when I reach 10 miles, I simply stop working at the treadmill desk and sit down. Not really a big deal, but it seemed a less than optimal situation, mostly because I don't have a true "sitting desk" that is ergonomically comfortable.

One obvious solution is just to walk a bit slower, and so I am doing that. There's nothing magical about 2 mph, after all. I am comfortable reading and typing at 2 mph, which I worked up to over time. But there is no need to walk faster, the real purpose is to stay standing up and moving through the day.

There are other benefits to walking a bit slower, not least being a bit less treadmill noise and a bit less perspiration. Not that 2 mph is fast enough to work up a true sweat, of course, but it's enough some days to make you feel a tad "gamey."

So for now, my typical pace on the treadmill desk will be 1.2 mph, unless I'm in the mood to walk quicker or slower. My total daily mileage will be lower, but my total time at the desk will likely be longer.

How fast do you need to go for an effect?

So, in the bassackwards manner that is all too typical for me, I went looking after the fact to see if anyone had measured the difference in caloric expenditure as a function of walking speed on a treadmill desk. And in 2006, the Mayo Clinic did.

Here is the article by James Levine and Jennifer Miller in the British Journal of Sports that demonstrates how effective the treadmill desk is. Table 1 from the study is expanded here. Energy expenditure per fat free mass (FFM) per hour is given, which means that if you know someone's mass, you can calculate how much they would expend per hour. Fat fee mass is not the same as total mass.

The obese subjects in the study had an average fat mass of 52% of total body mass. This is a BMI/ body fat calculator that uses the waist to height ratio to estimate body fat percentage. It seems to be based on the Navy circumference method. It's a rough measure that isn't precise, but It's adequate for this exercise.

Using the body fat calculator above, my number was about 35%, which I can believe because thought my BMI is now "healthy" my waist is still thicker than it should be. I am genetically inclined to add excess fat at my middle, and I have. And contrary to many fitness sites, I have not lost that fat first. As I've slowly dropped pounds I am slightly smaller everywhere, including my middle.

With a decent estimate of my body fat, I can use the information from the paper to calculate my energy expenditures. As a calculation based on an estimate, there's a limit to how useful the numbers will be. But as I don't think they are entirely useless, here are the numbers. These are calculations based on estimates and other calculations, so perhaps all they do are illustrate trends (which the original paper already did).

Activity	Energy/FFM/hr	Energy/hr
Resting	1.6	58.3
Sitting	1.75	63.8
Standing	2.01	73.2
Walking 1mph	4.83	176
Walking 2mph	6.2	226
Walking& Working	4.65	169.4

For the record, the energy per hour number seems very high to me, based upon what my treadmill tells me my calorie expenditure is. And of course, the treadmill's numbers are only based on its internal calculation using the distance walked that the weight that I enter. There is no way for me to enter my age on the treadmill.

The article made the point that while working the speeds were no more than 1.2 mph, and most were less. I suppose the difference could be in the action of typing, but they don't actually comment on that. So while not being entirely useless, I don't know how useful these calculations are.

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