The “1-minute” workout: not quite

The popular press has been all over a new study out of McMaster University in PLOS One that demonstrated that 1 minute of intense exercise in the midst of 10 minutes of lesser activity had similar cardiovascular benefits to 45 minutes of moderate exercise (in otherwise sedentary men).

The major novel finding from the present study was that 12 weeks of SIT in previously inactive men improved insulin sensitivity, cardiorespiratory fitness, and skeletal muscle mitochondrial content to the same extent as MICT, despite a five-fold lower exercise volume and training time commitment. SIT involved 1 minute of intense intermittent exercise, within a time commitment of 10 minutes per session, whereas MICT consisted of 50 minutes of continuous exercise at a moderate pace.

Which is neat, but the press headlines are all about the 1 minute part. Sadly. I would love to be convinced that exactly 1 minute of high knees could assuage my guilt of being sedentary and loving Cinnabon. But it’s not a 1-minute workout. It’s a ten-minute workout of which 1 minute hurts. That’s actually longer than the 7-min workout (app) that made the circuit a couple years ago.

This does dovetail nicely with this rundown in Vox summarizing the research demonstrating that, overall, exercise doesn’t help you lose much weight. This comes up all the time, and people are wrong about this all the time. Exercise is fantastic for you in so many ways, but its benefits aren’t primarily related to weight loss.

One 2009 study shows that people seemed to increase their food intake after exercise — either because they thought they burned off a lot of calories or because they were hungrier. Another review of studies from 2012 found people generally overestimated how much energy exercise burned and ate more when they worked out.

The popularization of nutritional science in general has led to a number of pervasive myths due to a conflation of correlation and causation (as well as bad science), like how millions of people still think that eating breakfast will magically make you skinnier.1

The overestimation of weight loss due to exercise is so pervasive in part because it’s so ostensibly logical. Exercise burns calories, therefore I should lose weight if I exercise. But even ignoring the hormonal and behavior/consumption reactions to exercise that can erase the calorie losses, I always just tell people the same thing when it comes to weight loss in the real world:

What you eat matters more. Which takes longer, eating the Cinnabon, or working it off?

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