Professional athletes don't train for cardiometabolic health. They train to perform at competitions. The study is perfectly fine for the people it is intended to serve in the context of their lives. Normal people neither want nor need to train like athletes. They certainly don't need to follow a training program to compete at the Olympics. But they would still be well served to train in some form because of their increasingly sedentary lifestyles. Optimizing that form for efficiency is a key to population health. This paper is just the latest in a stream of evidence that suggests shorter but higher intensity bursts of exercise might be the more efficient way of training if you want to min-max your workout time and health as a normal person who has a real job and possibly a family and other hobbies.

Just to add my interpretation of what Magness would say, which is: intense interval training tends to show significant gains over moderate work in shorter (8 weeks) study periods, but those gains level off quickly in the long term. A more blended training approach that incorporates all types of training intensities (hard, moderate, easy) will outperform just doing hard interval training, over the long term. And this advice applies to all types of athletes, not just people training at a high level.

> actual athletes

Probably need to define. Are we talking about professional athletes or just people who have a lot of training experience?

Exercising hard for a person who has never trained is very different than someone with years under their belt training. An untrained person can't even tap into what hard means compared to a trained person.

I'm also confused about the focus on endurance. Yes, all people need some cardio, but everyone would do better with additional strength. The stronger someone is going into their 50s, they better they will end up in the 60s and 70s.

But athletes don't have health as their main goal.

Isn't it likely that blended exercise is best for longevity anyway? i.e. per week 1-2h Zone 2 and 20 minutes HIIT (nordic 4x4?) and then as much strength training as you can fit in, say 3 x 1h PPL per week, and maybe some sauna too.

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".

Most people don't exercise at all. If some of these people draw the wrong conclusion from such a study and start exercising at high intensity, it will still be better than their current couch-potato training protocol.

Good and best is doing a lot of heavy lifting in your comment.

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.