Excessive exercise training causes mitochondrial functional impairment and decreases glucose tolerance in healthy volunteers, Flockhart et al, 2021

[darrellpf]

https://doi.org/10.1016/j.cmet.2021.02.017

"Exercise training positively affects metabolic health through increased mitochondrial oxidative capacity and improved glucose regulation and is the first line of treatment in several metabolic diseases. However, the upper limit of the amount of exercise associated with beneficial therapeutic effects has not been clearly identified. Here, we used a training model with a progressively increasing exercise load during an intervention over 4 weeks. We closely followed changes in glucose tolerance, mitochondrial function and dynamics, physical exercise capacity, and whole-body metabolism. Following the week with the highest exercise load, we found a striking reduction in intrinsic mitochondrial function that coincided with a disturbance in glucose tolerance and insulin secretion. We also assessed continuous blood glucose profiles in world-class endurance athletes and found that they had impaired glucose control compared with a matched control group."

 

[Creekside]

Until they come up with a reliable set of limits for exercise, I think we should all avoid excessive exercise. Just to be safe.

 

[Grigor]

I wonder what happens if you add a viral infection on top of it?

 

[alktipping]

as far as i am aware it takes three months for the human body to fully change from a non fit to fit state to what the military would call fighting fit . this experiment should have lasted 3 months .

 

[zzz]

[Edit: This post was merged from its own thread. I have rearranged a couple of lines of this post so that they make sense in the context of this thread. The original post was based on the New York Times article entitled Too Much High-Intensity Exercise May Be Bad for Your Health.]

Change the definition of "high-intensity exercise", and you've got us.

The subtitle of the article is, "A new study hints that excessive HIIT may harm your mitochondria, the energy generators found in every cell of your body." That sounds familiar.

The study referred to in the subtitle is Excessive exercise training causes mitochondrial functional impairment and decreases glucose tolerance in healthy volunteers in the journal Cell Metabolism. The link points to an abstract; the main article is behind a paywall.

It seems to me that the study hints that some of the mechanisms known to worsen ME/CFS (i.e., too much exercise) can cause similar problems in otherwise healthy people.