That intense exercise is good, and even very good for you, is proven as far as reasonably possible given that we can't run deterministically controlled experiments.
More evidence may come out that adds nuance, but the effect size is so large that it becomes obvious in the data just from observation.
You can cycle or stationary bike if you have bad knees. There are plenty of exercises that are intense but easy on the joints.
HIIT vs LISS is a false dichotomy. If you look at endurance athletes the most important part of the training is in "heavy domain" that is between what typical LISS and HIIT are. This is intensity high enough that you need to breathe faster but it's still sustainable for at least 40-70 minutes.
>>E.g. 5m all out effort is probably better, or at least equivalent, for health than a 30m moderate effort.
This is very unlikely to be true. Studies I've seen usually compare low intensity to HIIT and then measure things like VO2max improvements instead of direct health outcomes. VO2max is a good health indicator for general population and it's maximized short term by HIIT style of training but it's not enough to conclude short term improvements in VO2max imply long term health.
>>The average person can likely hit the 80/20 benefit threshold at less than 30m/week.
I very much doubt it. Usual number mentioned is at least 5 hours but in general the more the better.
There (for example) is High intensity interval training.
What that is depends somewhat on who you ask but to give an example.
Take a normal exercise like cycling for 45 minutes.
If you do HIIT you cycle as fast as you can for 10-15 seconds (or until properly worn out) then rest long enough to be able to do it again. You only end up working out for less than one minute or just half a minute in total but you get similar if not better results than the 45 minutes workout.
So yes, running up the stairs as fast as you can until you feel like you are going to die would be high intensity. Take the elevator back down or you might die for real.
That intense exercise is good, and even very good for you, is proven as far as reasonably possible given that we can't run deterministically controlled experiments.
More evidence may come out that adds nuance, but the effect size is so large that it becomes obvious in the data just from observation.
You can cycle or stationary bike if you have bad knees. There are plenty of exercises that are intense but easy on the joints.
Looking around, the simplest wording I get:
> the intensity must be high. This means that you need to really exert yourself so you get out of breath. [https://norwegianscitechnews.com/2026/05/exercise-a-very-lit...]
So if climbing the stairs gets someone out of breath it's intense (and I also see how getting to your limits, whatever they are, can help)
More and more studies have been indicating that even just a few minutes of intense exercise can outperform long/slow LISS type cardios.
E.g. 5m all out effort is probably better, or at least equivalent, for health than a 30m moderate effort.
The average person can likely hit the 80/20 benefit threshold at less than 30m/week.
For best results run fast and far. During my personal best marathon (3h 15min) my heart rate averaged in the 170 range
>>E.g. 5m all out effort is probably better, or at least equivalent, for health than a 30m moderate effort.
This is very unlikely to be true. Studies I've seen usually compare low intensity to HIIT and then measure things like VO2max improvements instead of direct health outcomes. VO2max is a good health indicator for general population and it's maximized short term by HIIT style of training but it's not enough to conclude short term improvements in VO2max imply long term health.
>>The average person can likely hit the 80/20 benefit threshold at less than 30m/week.
I very much doubt it. Usual number mentioned is at least 5 hours but in general the more the better.
What that is depends somewhat on who you ask but to give an example.
Take a normal exercise like cycling for 45 minutes.
If you do HIIT you cycle as fast as you can for 10-15 seconds (or until properly worn out) then rest long enough to be able to do it again. You only end up working out for less than one minute or just half a minute in total but you get similar if not better results than the 45 minutes workout.
So yes, running up the stairs as fast as you can until you feel like you are going to die would be high intensity. Take the elevator back down or you might die for real.