High-intensity interval training (HIIT), when performed correctly, is the most efficient method for increasing VO2 max and aerobic efficiency.

“hit if done correctly is going to be the most efficient way to increase your V2 max if your aerobic efficiency right if your Zone 2 is the base of the pyramid and your V2 Max is the peak of this pyramid then what you're maximizing what you want is the biggest area of the triangle possible that's what we're trying to maximize the area of the triangle we don't want a triangle that has a very very very very wide base but a teeny tiny little Peak right so that's great aerobic capacity no top end aerobic gear so that's a a short flat triangle that doesn't have a very high area similarly we don't want a triangle that has kind of a narrow base and a higher Peak uh that would be kind of not particularly good aerobic base but higher Peak aerobic output and again that will still by definition have a reasonable base uh but what I would argue is they're not even reaching the limit of their Peak”