[zfnmxt]

> There are adaptations that only happens during long easy sessions.

What sort of adaptations? As far as I'm aware, adaptations are the result of significant stress. What are the stressors of a "long easy session"?

At any rate, my post was about physical fitness and health, not how to become a competitive athlete.

Many competitive athletes are not fit. A marathoner who has no muscle mass and who is physically weak is not fit--regardless of the fact if they can run a 2:15 marathon. Said marathoner is not resistant to adversity, e.g., consider how they'd do on a wasting disease like cancer versus an athletic 215lb male.

What competitive athletes do generally is not a useful consideration when deciding on training modalities. Assuming that what the pros do is effective because they're pros is logical fallacy and, regardless, these people are (genetic) outliers with differing goals.

Low-intensity, long endurance cardio is adversarial to increasing strength. If you want to be a competitive endurance runner then, sure, you need to adapt your training and you will need to do long endurance cardio. If you're just an average Joe who wants to be healthy and fit then it is not in your interest to do long endurance cardio. Injury rates are higher, it makes it harder to become strong, and many of the resulting adaptations are undesirable.

[multjoy]

Someone who can lift 440lbs but who sweats when they eat isn't fit, either.

>What sort of adaptations? As far as I'm aware, adaptations are the result of significant stress. What are the stressors of a "long easy session"?

The adaptations come from the cardiac system. Basically, the body can use more oxygen more efficiently.

>Low-intensity, long endurance cardio is adversarial to increasing strength

Increased strength is adversarial to improved cardio efficiency.

[zfnmxt]

> Increased strength is adversarial to improved cardio efficiency.

This is absolutely untrue. If you take a runner who doesn't squat and get them to squat (and get stronger) they will become a better runner. By becoming stronger, each stride becomes more submaximal. Of course how strong they can become will be modulated by how much weight they can gain--in the case of a runner, that will probably be a very modest amount before the increase in weight begins to negatively impact their performance. But even with extremely minimal weight gain, they can become significantly stronger from an untrained state in a way that only positively impacts their running performance.

> The adaptations come from the cardiac system. Basically, the body can use more oxygen more efficiently.

You misunderstood my question. If the session is easy, what is the stress which sufficiently disrupts homeostasis to lead to an adaptation? Easy things do not result in adaptations.

> Someone who can lift 440lbs but who sweats when they eat isn't fit, either.

Sure, they should do their cardio.

[multjoy]

>If the session is easy, what is the stress which sufficiently disrupts homeostasis to lead to an adaptation? Easy things do not result in adaptations

An "easy" run is a stressor on the cardiac system, because you don't spend all day with an elevated HR and commensurate lung work.

[zfnmxt]

Everything is a stressor. Doing nothing is a (negative) stressor. The question is is it a sufficient stress. And it is not.

Squatting 120 kg x 5 every day is a stressor, and provided you do no other strength training, it will feel hard. But you'll never get stronger than you already are.

[multjoy]

>Everything is a stressor. Doing nothing is a (negative) stressor. The question is is it a sufficient stress. And it is not.

You are wrong.

[mutatio]

> The adaptations come from the cardiac system. Basically, the body can use more oxygen more efficiently.

I'm quite sure HIIT is near optimal for improving VO2max - and if you look at it through the less of time vs. benefit then it's unrivalled in terms of cardiovascular health.

[multjoy]

Arguably it's the only way! A rising aerobic tide lifts all boats...