I did my first
HIIT exercise this morning: a total of 20 minutes of exercise including the warm-up and cooling down periods and I've got mixed feelings about it.
I sat in a Concept2 rowing machine, warmed up slowly for five minutes, did ten HIIT cycles (heart rates: 30 sec at around 130-140 bpm, 30 sec at 170+ bpm) and cooled down for five minutes.
After everything I had read and heard about how intense HIIT is, my initial thought was: "That's it? I don't feel like dying, so did I do something wrong?". Sure it was intense and I was sweating and panting like crazy, but I could have pushed even harder if the bloody machine would have let me. I've done more intense (180-190 bpm) climbs while biking, so this felt like child's play compared to those. When I was leaving the locker room I was still trying to figure out how I could have made the exercise more intense.
However, the "afterburn" I got indicated that the exercise did actually work - I was sweating like a pig for about an hour after the workout, which is something that rarely happens after my usual 40-45 min bike ride (average heart rate: 150-155 bpm) to work. I guess there really is some magic in that alternating low intensity/high intensity system.
Some observations:
10 minutes is too long at this early stage. Not because it was too intense, but because the idea of HIIT is to keep the exercise time short. If you look at the HIIT charts, they usually start at 4 min and eventually increase up to 15 min effective time (excluding warm-ups and cool-downs). They are, however, designed with running in mind and since rowing is probably less intense than running, I should probably increase the duration of the jogging-sprinting periods from 30 s to 1 min.
The rowing machine sucked in two ways. Firstly, the straps that were supposed to keep my feet in place kept getting loose. Secondly, the resistance/load was already maxed out, so I couldn't make the exercise more intense that way (and rowing faster than the 57-60 rows per minute I was doing during the sprints wasn't really possible either). Fortunately, as I said above, I can make the sprint periods longer, so the intensity is not as much as a problem as the thing with the straps.
I don't know how many calories an HIIT session burns. The exercise itself burns only about 200 kcal, but how to figure in the afterburn? This kind of sucks, because I really like having a fairly accurate estimate of my daily energy balance. But yeah, I know that the trend in the size of my Ring of Fat will be the ultimate indicator of that balance...
HIIT rocked! Psychologically this was exactly what I want from an exercise in the first place: high intensity and short duration. That's why I like weight training and biking up hills, but HIIT was even better. It's an exercise that's so intense that it makes it impossible to think anything else than the clock and the next 30 seconds. My daily job involves nothing but hard thinking, so it's nice to be able to turn the brain off for a while.
I'll keep doing HIIT now for a while, try to fine tune it for myself and see how it feels like. If it's still good after about a month, I'll probably give up normal biking in the winter and do HIIT instead.