The research I’ve seen on exercise non-responders has been pretty preliminary. A standard study gives a bunch of people an exercise routine, and measures some fitness-related variable before and after. The amount of improvement on that fitness-related variable has some distribution, obviously, because there are various sources of noise, context, individuals differences between people. You can look at the left tail of that distribution—the people who had little or no or negative improvement on this fitness measurement over the course of the study—and say that they were “non-responders” to this exercise intervention.
One hypothesis for why that happened is that there is some stable & general individual difference, something about their physiology, which makes it so that they wouldn’t respond much to pretty much any exercise routine that they tried.
In order to see if that’s what’s going on, rather than the various other things which could cause this measure of a person’s fitness to fluctuate, or attempts at this exercise routine to have more or less of an effect, you’d have to do some more research to understand what’s going on with these people in more detail. But for the most part that additional research doesn’t get done, people just talk about the people whose fitness measurement didn’t change much from this intervention as if being a non-responder or a low-responder is a stable trait of theirs. That’s the case with the first study cited in this twitter discussion.
In the replies to that tweet, someone links to one paper which did continue to study the non-responders to an exercise intervention, just trying more dakka (more training sessions per week), and found that every person ended up with some improvement.
The research I’ve seen on exercise non-responders has been pretty preliminary. A standard study gives a bunch of people an exercise routine, and measures some fitness-related variable before and after. The amount of improvement on that fitness-related variable has some distribution, obviously, because there are various sources of noise, context, individuals differences between people. You can look at the left tail of that distribution—the people who had little or no or negative improvement on this fitness measurement over the course of the study—and say that they were “non-responders” to this exercise intervention.
One hypothesis for why that happened is that there is some stable & general individual difference, something about their physiology, which makes it so that they wouldn’t respond much to pretty much any exercise routine that they tried.
In order to see if that’s what’s going on, rather than the various other things which could cause this measure of a person’s fitness to fluctuate, or attempts at this exercise routine to have more or less of an effect, you’d have to do some more research to understand what’s going on with these people in more detail. But for the most part that additional research doesn’t get done, people just talk about the people whose fitness measurement didn’t change much from this intervention as if being a non-responder or a low-responder is a stable trait of theirs. That’s the case with the first study cited in this twitter discussion.
In the replies to that tweet, someone links to one paper which did continue to study the non-responders to an exercise intervention, just trying more dakka (more training sessions per week), and found that every person ended up with some improvement.