(www.cell.com)
In brief, the training protocols used in these papers are not representative at all of how actual athletes train. And athletes do not train that way because it doesn't work nearly as well as the training protocols that have become popular since the 1960s or so.
With this I am not trying to invalidate the research. What I am doing is warning laypeople from drawing overly simplistic conclusions from studies like these, such as concluding that "Exercising hard is good". Successful endurance athletes spend the overwhelming majority of their training at low and moderate intensities, because that is what works best in the long term.
This is likely around what is best for most people and probably cutting the strength training time to 1h before cutting the rest if you "don't have time".
What are you talking about when you speak of good/best outcomes? I think especially when it comes to talking about fitness it is important to be explicit about outcomes because only with outcomes in mind can you talk about what “good” actually means.
In that context I’m a bit confused by your focus on (endurance) athletes. Their overriding goal is obviously increasing their athletic performance in a way that keeps them injury free. Their main focus aren’t health outcomes. That’s not the same. So if you focus on them you are in danger of talking past each other.
To that point: sure, those studies often have unrealistic protocols but the way (performance) athletes train is also unrealistic for most people!
If those studies are about population health they should have realistic protocols (in terms of: realistically achievable and adhered to by non-athletes, in the best case also empirically grounded in the sense of: this is a realistic range of activities non-athletes might actually engage in on a regular basis) for non-athletes.
Despite doing exercise (including high intensity stuff like spin class) I was overweight and had a HOMA-IR of 3.8 (Moderate Insulin Resistance) and insulin 13.2 (Early Insulin Resistance).
This was because I was addicted to sugary stuff.
I cut my refined sugar intake to almost zero and in two months HOMA-IR went to 1.02 (Normal Range) and insulin to 4.9 (Optimal / Longevity Range). My triglycerides had peaked at 228 (Moderate Risk) and dropped to 96 (Normal/Good). Glucose went from 116 (Prediabetes) to 85 (Healthy).
My assistant in cutting all that sugar was Claude. I used Claude as my buddy: I'd chat with Claude when I had cravings and it gave me alternatives and support. And it worked.