Intense Exercise Lowers Activity, Body Temp, Tied to Weight Gain | Hacker News Reader

Intense Exercise Lowers Activity, Body Temp, Tied to Weight Gain

journals.lww.com

8 pointsgnabgib9 comments

Reminds me of: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4989512/

"Persistent metabolic adaptation 6 years after The Biggest Loser competition (2016)"

"After 6 years... RMR(resting metabolic rate) was 704±427 kcal/d below baseline..."

I wish they had gone more into depth about standardizing for mass and fat-free mass and presented data in units /kg/day (instead of just /day). They say they did standardize, but at a glance I didn't see much more detail. Obese people have massively elevated RMR compared to non-obese people (when reported as kg / day).

They still had retained an impressive amount of weight loss after 6 years (compared to most free-living participants in dietary intervention trials), and RMR is of course going to be proportional to your body mass.

The article does not make clear what type of weight is gained but I'd wager a guess that it is caused by water retention and as such a well-known phenomenon - just do a search on water retention after exercise and you'll get loads of results.

(in mice)

I'm not familiar with the medical field. To what extent does experience using mice translate to humans?

None.

It just gets the phenomenon flagged as something that needs to be studied in humans.

> Notably, Only the vigorous exercise group exhibited a decline in both NEPA and BT, resulting in body weight gain the following day

Yeah, no kidding... I also gain weight the day after vigorous exercise. Mostly muscle mass, probably maybe some water retention, bone density, I'm not sure. Pretty much every time I have a reduction in fat mass.

(I'm no doctor but) I struggle to imagine that bone density can change within a day. For that matter I'd be shocked if actual muscle mass changed; I'd personally wager that its almost exclusively water weight (if nothing else, more blood getting allocated as your body does maintenance).

I'm no doctor either, so the below is mostly guessing.

I imagine bone density as well as any other biometrics change constantly. How much over the course of however long, I don't know.

I weigh myself daily on a scale with bioimpedance. I understand that this is not the most accurate way to measure body composition but it's something. My bone density is different every time I weigh myself, and it has some correlation with diet, exercise and water intake. Again, how much this is accurate or reliable, I don't know.

> I'd be shocked if actual muscle mass changed; I'd personally wager that its almost exclusively water weight

Given that a huge percentage of cell mass is water, you're likely correct. That means muscles get bigger and better hydrated. That should in turn make them stronger and more resilient. That's muscle building. The other bits (more organelles, etc) may or may not take longer to follow (again, not a doctor, not a biologist) - I have no idea.

In any case, the "study" more or less guesses that more exercise means weight gain due to reduced basal energy expenditure. That may be the case, but that's fine. Weight gain due to muscle mass is desirable.

The problem is that the phrase "weight gain" is normally used in contexts where it means fat gain, which is undesirable and dangerous for one's health.

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