Comment by twawaaay | Hacker News Reader

Comment by twawaaay | Hacker News Reader

Everybody knows that high intensity exercise does more than low intensity ones per hour invested. At least in running world.

The issues are, and especially when you are out of shape:

* adherence -- it is difficult to keep people do hard, high intensity exercises regularly. Part of being a runner is learning to deal with pain but people who are out of shape are almost by definition new to this and are not yet accustomed to pain.

* injuries -- especially when you are out of shape, the goal should be consistency over quality. Any injuries will immediately put you out of your high intensity training. And high intensity training with out of shape people is a recipe for lots of injuries.

* volume -- while you can do a lot more per minute on high intensity exercise, you can do a lot more low intensity volume. You can quickly and safely build up to be able to do half an hour of slow jog a day even if you are overweight and out of shape.

* recovery -- high intensity exercises have high recovery requirements. Do out of shape subjects know how to massage their muscles? How to stretch? How long to recover? Recovery will further cut the volume of training. An out of shape person may need 3-4 days of recovery after a short but hard, intense interval session. Normally, this is filled with low intensity running and intense sessions are limited to once a week to give time to recover.

Even elite runners recognise how dangerous it is to do large volume of high intensity exercises and there is very popular, successful movement now to almost exclusively low intensity exercises and reserving high intensity mostly for the last stretch before the event. The main goal of this is to ensure injury-free training.

So if I was taking care for out of shape patients and prescribing training regimen I would still tell them to do, for starters, easy, comfortable jogging rather than any high intensity exercise.

> Everybody knows that high intensity exercise does more than low intensity ones per hour invested. At least in running world.

No. This is actually wrong. You should read Scott Johnston's "Training for the Uphill Athlete" to understand why.

I read that book, and as with most other sources of information about endurance training, I found it to be very focused on the situation where people are limited by their recovery budget. I couldn't tease out what the guidance would be for someone who only works out 3-4 hours per week. There would be physiological explanations of the unique value of low-intensity training, and I would think, "Sounds like this applies to everyone," but then there would be an implicit reference to overtraining. Eventually I came to the conclusion that everything in the book assumes that you're training so many hours per week that even if 70% of it is low-intensity, you're still stretching the limit of your ability to recover.

I haven't made an exhaustive search or anything, but I've repeatedly been frustrated by this pervasive assumption when looking for information about endurance training. I guess this makes sense, because even the amateurs I know who love endurance sports work out 10+ hours per week. I just don't love it that much.

I've found one single piece of advice (and again, I haven't made an exhaustive search or anything) in a podcast interview[0] with an expert on and advocate of polarized training for cyclists. In response to a listener question, the expert said that if he only had four hours per week to train, he would "just hammer... and hope for the best," meaning train as intensely as he was able.

[0] https://www.youtube.com/watch?v=Ju3McjlSoAg&t=702s (11:42)

Perhaps your next read should be Mark Twight’s essay aptly titled TNSTAAFL.

> Everybody knows that high intensity exercise does more than low intensity ones per hour invested. At least in running world.

“Does more” is hella vague. As a 40-mile a week runner I find that low intensity runs “do more” for me because they’re more relaxing.

I mean, I think I understand what they're saying. A thirty minute tempo will develop your aerobic capacity more than a thirty minute easy run-- more or less analogous to progressive overload in weightlifting. That's not to say that you can't grow/improve as a runner without challenging sessions, but I imagine the rate of improvement would be significantly lower. Pro runners would be doing as many workouts as possible per week if recovery weren't an issue!

I used it in a "scientific" way. If you were able to put the same person to do two exercises, one 60 minute easy run and second time 60 minutes tempo run (and possibly also time travel inbetween both sessions so they are in the same state at the start) you would measure that in the universe where you did the tempo run you would improve your fitness more (unless you were somehow injured/overtrained and not ready for the tempo run).

This is where the part "per hour invested" comes.

Most people can't do an hour of tempo run every day without getting themselves overtrained and injured. And if they could do it physically, it would be enormous mental challenge.

Switch to most of us like you and me -- an easy run provides most of the benefit per hour invested but in a sustainable way, meaning you will be able to invest more hours and do it consistently. And you will be more likely to stick to do it every day if you find it refreshing and relaxing rather.

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