4 minutes of hell

There is an old saying about "Pride comes before the fall". After reading some of the various blogs here recently I came across some mention of cross fit training and Tabatha training. A cross fit training video showed these two guys doing some Tabatha training on the treadmill. am watching and thinking, I think I can do this, after all I can run 5 K at a reasonable rate (about 26 min) and these guys are only running for less than 4 minutes.
Treadmill set at highest incline (12 in this case). Speed set to 7 (in my case), you run for 20 seconds, hop off for 10 seconds, on again for 20 seconds, etc. For a total of 8 intervals. All in all that means 8 times 30 seconds, done in 4 minutes. So, that cannot be that hard right, 20 sec.. ha. that is nothing.
I tried it. Oh was I ever wrong. One of the absolute hardest things I have ever tried on the treadmill. My lungs still hurt 15 minutes later. Sucking wind like no tomorrow. So, this will be my new gold standard to determine how fit I really am. I will probably set the speed to only 6 so that I have a chance to NOT die while I try to complete 8 of those. I guess more and more research shows short challenging intervals result in greater benefits than long sustained running, and are also easier on the body in the long run. I have new respect for my old treadmill.