This is the first time I’ve ever seen a health & fitness blog post with this many scientific claims I had already researched independently, where I could not find anything that I materially disagree with!
Unfortunately, I haven’t yet managed to build solid-feeling models, so I both (a) don’t have very much I want to say about it here, and (b) haven’t managed to incorporate it into my life in a way that’s satisfying. Basically I think aerobic exercise is in fact extremely good for you, but I don’t have a strong sense of exactly what kinds of aerobic exercise are best for you, per unit of effort. I’m not claiming that the literature doesn’t have clear answers here; merely that I don’t know what they are (though I have tried a bit, and my impression is that the story of what works well for cardiovascular health is more complicated and has less overall consensus than what works well for skeletal muscle).
I don’t know much about this but FWIW according to my research, I found the situation with cardio to be qualitatively similar to the situation with resistance training. Which is to say, you can find a lot of people saying method XYZ is the best, and there’s some research to back them up; but on the whole, what the research primarily shows is that exercise is way better than not-exercise, but as long as you’re exercising, it’s not super clear what’s optimal.
Examples:
A lot of people say high volume resistance training is better, a lot of people say low volume is better, but AFAICT the literature is basically ambiguous. On its face, the research points toward high volumes being better, but there are caveats—the high-volume studies often have people training only a single muscle group, which is not realistic.
A lot of people say HIIT is the best cardio, a lot of people say moderate-intensity steady state is better, but AFAICT the literature is basically ambiguous. On its face, the research points toward HIIT being better, but there are caveats—the studies usually don’t last very long, and athletes often report that doing high volumes of HIIT for a long time leads to burnout.
For HIIT, see this graph of VO2max improvement vs. study duration. HIIT went up faster than endurance training (ET), but if you extrapolate the curve, it looks like the benefits are leveling off faster, too. But the study durations are too short to say with confidence.
For the question of “what kinds of aerobic exercise are best for you, per unit of effort”, I think the denominator is the deciding factor, and effort is subjective. So the best aerobic exercise is whatever feels best for you.
An additional unclear thing about HIIT is that we don’t really know with confidence that VO2max causally improves the things we “really” care about. I mean… as you say, any exercise that improves VO2max almost certainly improves health (a lot), but it’s entirely possible that exercise program A might improve VO2max slightly less than exercise program B and yet exercise program A might be better for health.
(Totally endorse your logic in the last paragraph BTW. I think, if anything, this strengthens that argument?)
This is the first time I’ve ever seen a health & fitness blog post with this many scientific claims I had already researched independently, where I could not find anything that I materially disagree with!
I don’t know much about this but FWIW according to my research, I found the situation with cardio to be qualitatively similar to the situation with resistance training. Which is to say, you can find a lot of people saying method XYZ is the best, and there’s some research to back them up; but on the whole, what the research primarily shows is that exercise is way better than not-exercise, but as long as you’re exercising, it’s not super clear what’s optimal.
Examples:
A lot of people say high volume resistance training is better, a lot of people say low volume is better, but AFAICT the literature is basically ambiguous. On its face, the research points toward high volumes being better, but there are caveats—the high-volume studies often have people training only a single muscle group, which is not realistic.
A lot of people say HIIT is the best cardio, a lot of people say moderate-intensity steady state is better, but AFAICT the literature is basically ambiguous. On its face, the research points toward HIIT being better, but there are caveats—the studies usually don’t last very long, and athletes often report that doing high volumes of HIIT for a long time leads to burnout.
For HIIT, see this graph of VO2max improvement vs. study duration. HIIT went up faster than endurance training (ET), but if you extrapolate the curve, it looks like the benefits are leveling off faster, too. But the study durations are too short to say with confidence.
For the question of “what kinds of aerobic exercise are best for you, per unit of effort”, I think the denominator is the deciding factor, and effort is subjective. So the best aerobic exercise is whatever feels best for you.
An additional unclear thing about HIIT is that we don’t really know with confidence that VO2max causally improves the things we “really” care about. I mean… as you say, any exercise that improves VO2max almost certainly improves health (a lot), but it’s entirely possible that exercise program A might improve VO2max slightly less than exercise program B and yet exercise program A might be better for health.
(Totally endorse your logic in the last paragraph BTW. I think, if anything, this strengthens that argument?)