High intensity, high effectiveness.

"Cardio is dead," spoke Zarathustra... or something like that.

Recently there has been the beginning of a much needed shift away from traditional forms of long slow distance (yes, it's referred to as LSD) cardiovascular exercise towards higher intensity forms of interval training. There is still a place for longer, paced cardio, especially if you participate in activities that are continuous and of long duration (mostly long distance running/cycling/swimming events); however, if your goal is body recomposition - fat loss or the gain of lean muscle mass - LSD is a largely outdated and inefficient means of achieving your goals.

High-intensity interval training (henceforth HIIT) is a relatively straightforward concept. Periods of higher intensity are alternated with periods of lower intensity for a given duration. There are many time variations for these, with the high intensity intervals ranging anywhere from about 8 seconds to a couple minutes. What is important is that during the high intensity interval, the individual is working hard. You need to be working at a pace greater than your ability to recover, preferably much greater, to really receive the benefits.

Here we have a study demonstrating the effectiveness of sprint intervals of cycling compared to a more traditional training method in terms of improving performance. Results demonstrate similar improvements despite the fact that the interval group performed 4-6 bursts of 30s of maximal effort activity with 4 minutes of recovery in between compared to 90-120 minutes of continuous cycling. That's 2-3 minutes of actual work per session versus almost 2 hours! If that's not efficient, I don't know what is.

When it comes to fat loss, interval training wins again. This study concludes that "HIIE three times per week for 15 weeks compared to the same frequency of SSE exercise was associated with significant reductions in total body fat, subcutaneous leg and trunk fat, and insulin resistance in young women."

And even better here! Of particular note is that: "Despite its lower energy cost, the HIIT program induced a more pronounced reduction in subcutaneous adiposity compared with the ET program. When corrected for the energy cost of training, the decrease in the sum of six subcutaneous skinfolds induced by the HIIT program was ninefold greater than by the ET program."

While this doesn't mean that HIIT is nine times better than endurance training, it does help demonstrate that for a given portion of time or energy, HIIT is dramatically better at reducing body fat.

I'll be expanding upon this in my next post, discussing how we can further improve this powerful effect and providing some specific exercise examples for incorporating HIIT-based conditioning into your workouts.

In summary: high intensity conditioning methods are much more effective at reducing body fat and even more effective when considered at a per unit of time basis. Longer paced cardiovascular activity tends to be accompanied by an increase in food consumption, often resulting in a lack of progress. Incorporate interval based exercise into your workouts if you have goals based around fat loss or staying lean.

- Jonathan