Saw it but im proud to be a chronic cardio lover

Interesting. I'm a Personal Trainer and since this show I've had several people tell me that doing 3 minutes exercise per week is better than doing 3 hours of exercise per week.

Obviously the show is based on actual research and what they say is true although largely misinterpreted. The concept of HIIT (High intensity interval training) has been around for several years and is based on something called the EPOC effect or "Excess Post-Oxygen Consumption". This effect states that high intensity exercise leaves us with an elevated metabolism for a longer period after our workout than a low intensity workout would. Essentially, the theory says that the higher the intensity of the exercise, the longer the EPOC effect lasts. So in theory, if we work as hard as we possibly can for a short period of time, well experience the maximum duration of elevated metabolism.

However it doesn't get away from the fact that the actual time spent working out accounts for the majority of the calories burned. A good hour of exercises (which incidentally should consist of some high intensity training) will burn up to and around 1000 calories, depending on the individual. 1 minute of high intensity training is likely to burn around 15-20 calories.

If the EPOC effect meant that post exercise, our body burned more than an extra 1000 calories whilst not exercising, which is essentially what they are saying, then there would be an argument for only doing 1 minute instead of an hour, however that would only be true if the hour of exercise was very low intensity exercise such as yoga, tai chi or walking.

If, for example, you did a high intensity circuit training session or a 10k run with a sprint finish, you'll be putting your body through the necessary levels to generate sufficient EPOC effect, whilst also benefiting from the extra 1000 calories burned DURING the exercise session. Win-Win!

The short period of time that they are suggesting comes from the fact that we can only sustain that type of intensity for around 20 seconds before we have to slow down. The truth is that we can recover from this within a few minutes and perform it again, and again, and again which enables us to do this activity for a much longer time than 1 minute. This is also more likely to promote changes in your muscle size and strength which also requires excess fuel for growth over the next few days in fact.

So in short, a full workout will benefit you more assuming you reach sufficient intensity during the session.

See also Tabata Training and DT Training