But I started doing HIIT last week on my bike (on indoor trainer). I warm up for 10 minutes and then do 4 intervals as hard as I can with each followed by a rest period in which I ride a normal pace until my heart rate drops down to the normal riding level (about 135 in my case). After each HIIT session, I ride for another 5 minutes or more to cool down.
Though this is entirely anecdotal, I have already noticed significant changes not only in physical fitness, but in mental and behavioral ways.
In the video linked up above a doctor says "ride" (or run, row, etc.) like you are trying to escape a wild animal (i.e. full adrenaline rush).
That's the way I do my HIIT and the result so far (if they are not entirely only in my mind) are significant.
More energy, feel strong and verile, powerful dreams, and *gasp* greater libido (not too sure what to do with that).
“and *gasp* greater libido (not too sure what to do with that).”