HIIT Protocol from a Cardiologist
I had this fascinating conversation with a cardiologist today...
She was explaining the benefits of high intensity interval training (or HIIT or metabolic conditioning) from her perspective.
She says that the way you should gauge the intervals should be like this: (I just tried it out before posting so I could make useful comments)
1. Each interval should be for a minute 2. The last 20 seconds of that minute you should be breathing **REALLY** heavily (she demonstrated by panting hard) 3. The first 20 seconds of your recovery interval (which can be as long as you want/need it to be - it took me 2 minutes to recover fully!!) you should be breathing equally as hard 4. You should do this 8-10 times (fuck! I did it 6 times just now and it took me 25 mins - and I got a really good workout out of it - and so did my dog. I actually only stopped because I was worried I'd be bringing home a dead animal - can't say I didn't relish the excuse to walk home) 5. You should do this twice a week
I did it running - but you can bike, swim, use a cross-trainer or do burpees - in this sense the heart is a dumb muscle.
We know by now that this is a much more effective way to exercise than steady-state cardio in terms of fat loss, and it releases a hell of a lot of endorphins - but what I found really fascinating was how she related it to heart health.
She explained that when we go into that really heavy breathing state, it's a sign that we've exceeded the limitations of the Krebb's cycle (which is basically the metabolic pathway by which we create energy from oxygen and glucose - in other words, aerobic respiration) and start metabolizing fatty acids and most notably LDL the 'bad' cholesterol.
We create a huge oxygen debt and the way we metabolize energy is really inefficient (which means we need more energy to do it).
In short, it lowers blood triglycerides, cholesterol, strengthens the heart, metabolizes fat AND you get a serious buzz off it!!
I'm not sure if I can do this twice a week, and I certainly won't be doing it with running (I don't enjoy it enough), but it's certainly made me think hard about how to structure conditioning workouts.
I have since tried this protocol with different exercises. I had a session recently where I took an exercise, did it continuously until my heart-rate was sufficiently high (above 180 - OR that I was panting as described above) - this usually took 60-90 seconds, depending on the exercise. I rested until my heart rate was back down to 120-ish (this sometimes took 3 minutes or more) and then did a different exercise. I tried it with the following exercises:
2. Clean and Jerk with a kettlebell
3. Clean and Jerk with a barbell
4. Dumbell snatches
5. Assault bike
7. Box jumps
8. Double Unders
I found that by changing the exercises, I still got my heart rate really high, but I enjoyed the workout so much more. When I limited it to just running, I dreaded the next set, and found it hard to push myself.
Recently, I have also taken up tennis as a fun thing to do on a Saturday with my friends and husband. What I noticed was, during the hour, my heart rate would go up and down, and there were often bursts of sprinting from side to side where my heart rate would get as high as 180, but then I would have a chance to rest, my heart rate would come back down and I then I would have to work hard again. Over the hour, I burned around 600 kcals - similar to if I had run a 10K in that time. But rather than my heart rate remaining at a steady pace, it went up and down between 120 and 180 the whole time.
I came to the realisation that this is perhaps why sports like tennis, netball or volleyball might be a great for our cardiovascular fitness, because they push us into that red-zone where we are breathing hard and working different metabolic pathways.
So there are lots of ways to do this kind of cardiovascular training, and it's likely to have more health benefits, be better for fat-burn and body composition AND be more fun than steady state aerobic exercise.