I’d be interested to see your HR response to these vs. longer intervals, (e.g. 4x4 min “all-out” VO2max style, for approximately the same working time). In my n=1 case, I can’t imagine I would get anywhere near the same ventilatory rate or HR from 40/20s as I do from the long stuff. I just haven’t found much use for 40/20s and such other than a sharpening workout in peak, but interested to see what others find out here.
E.g. here’s today’s 4x5 hard start/high cadence VO2 workout… by the end of these I can’t possibly breathe any harder, my HR is basically at maximum (179bpm and I’ve only touched 180bpm this season otherwise) and there’s usually lines of spittle involved. Also, the computer auto-pauses (I need to turn that off) because I’m about fall off the bike. I’ve never gotten that same thing from 40/20s, but maybe I’m not doing them long/hard enough…
