Or rather, on how the “almost completely sedentary” in “Very Obese Adults Almost Completely Sedentary” is defined. The full text of the study isn’t freely available, but the abstract is linked in here. The results include:
On average, subjects took 3,763 ± 2,223 steps.
That implies a range between 1,430 and 5,986 steps a day. That’s a pretty wide range of data, and makes me wonder whether they really found anything other than “people are variable”.
On average 23 h and 51.6 min per d were spent sleeping or engaged in sedentary activity (<3 metabolic equivalents [METs]) and the remaining 8.4 min were spent in moderate activity (3-6 METs).
I’m not too familiar with metabolic equivalents, so I went to Google and found:
The Metabolic Equivalent of Task (MET), or simply Metabolic Equivalent, is a physiological concept expressing the energy cost of physical activities as multiplies of Resting Metabolic Rate (RMR) […]. By convention 1 MET is considered as the resting metabolic rate obtained during quiet sitting. MET values of physical activities range from 0.9 (sleeping) to 18 (running at 17.5 km/h).
Although the RMR of any specific person may deviate significantly from the above mentioned conventional reference value, MET values of physical activities provide a rough indication of the intensity of physical activities such as manual labour or exercise. MET is actually an index number and not an energy unit: a physical activity with a MET value of 2, such as walking at a slow pace (e.g., 3 km/hr) would require for a specific person twice the energy that person consumes at rest (e.g., sitting quietly).
Wikipedia also has a chart showing how METs roughly translate into activities. The section for “<3 METs” is titled “Light Intensity Activities”, and includes watching TV, working at a desk and walking 2.5 miles an hour or less. That’s the range that the researchers labeled “sleeping or sedentary activity”.
So that 99% of the day that was spent “sleeping or engaged in sedentary activity”? Includes time where the people were walking, probably doing light housework, and other tasks.* Not exactly the impression given by the abstract (“On average 23 h and 51.6 min per d were spent sleeping or engaged in sedentary activity”) or Reuters: “[P]articipants spent an average of 23 hours and 52 minutes sleeping, lying down or sitting each day.”
I also note that the deviation wasn’t given for the amount of time spent in sedentary and light activity, just the average. Just how much variation was there, hm…?
* This is the point where I should probably say something about how fat people should work to get a half hour of moderate-intensity activity a day, but you know what? It’s like flossing or brushing your teeth. Yes, it’ll probably help your health if you do it, and it may have a big impact on your life down the road, but it doesn’t inherently make you a better person and you don’t owe it to anyone else.
Leave a Reply