An instant H.I.I.T. (page 1 of 2)

HIIT refers to training intensely for short bursts followed by similar periods of low intensity. HIIT workouts are usually short but intense and burn a large number of calories in a short period of time.

In 1994, an important study was conducted over a 20-week period with 17 test subjects. One group was instructed to perform between 30 to 45 minutes of steady-state cardio. They began the program exercising at 60% of their target heart rate and increased this to 85% over the 20 weeks. The second group performed 30 minutes of HIIT training. They would warm up at 70% of target heart rate, then perform intervals of 10 seconds at lower heart rate and 90 seconds at higher heart rate, followed by a less intense period allowing their heart rate to drop before beginning the next interval. Interestingly, the second group expended less energy during their training sessions. However, over the 20-week period, they lost almost three times as much fat. This fat loss was specifically underneath the skin (subcutaneous fat).

HIIT training creates a demand for Excess Post-exercise Oxygen Consumption (EPOC). In order to restore the body to a resting state and adapt to the load of the exercise, the body must use excess oxygen after the workout is completed. This effect can last for hours and even days. In a 2002 study (Schuenke, M.D., Mikat, R.P., McBride, J.M. Effect of an acute period of resistance exercise on excess post-exercise oxygen consumption: implications for body mass management, European Journal of Applied Physiology 86:411-417, 2002) a measurable increase in resting metabolic rate was found two (2) days after the exercise was performed.

These findings have important implications for training and specifically fat loss. First, you may burn more fat underneath your skin performing HIIT sessions than traditional "steady-state" sessions such as long runs or bike rides. Second, you may be able to create a measurable positive impact on your metabolism. For people who are restricting calories to lose weight, this means more calories will be available to consume without hindering fat loss. Finally, those with a hectic schedule can burn fat without spending hours in the gym. In fact, most HIIT workouts last only 20 minutes or less - despite potentially burning more fat than longer sessions lasting an hour or more!

To create your own HIIT workout, keep the following parameters in mind:

1. The workout should include short, intense bursts of activity
2. These should be followed by periods of active recovery - you will still be exercising, but at a lower intensity to allow your heart rate to return to normal
3. HIIT sessions typically should not last more than 20 - 30 minutes

One popular variety of HIIT involves using several intervals. To construct the program, follow these steps:

1. Pick a pace that is very comfortable for you - you are exercising but are able to carry on a normal conversation. Call this "50%".
2. Pick another pace that is almost "all-out" (like a sprint) and call this "100%".
3. Now, build your intervals based on these percentages

You'll perform 2 - 5 minutes of a warm-up at level 50%. Then, spend 1 - 2 minutes at level 60%, followed by 1-2 minutes at 70%, then 80%, then 90%. Repeat this several times and finish with an extra minute or two at 100%, followed by a 2 - 5 minute cool down at 50%.

As an example assume you are comfortable warming up at 8 kilometers per hour and feel your 100% is 14 kilometers per hour.

Your first week of workouts may look like this:

5 minutes at 8 kph
The sequence:
1 minute at 9 kph
1 minute at 10 kph
1 minute at 11 kph
1 minute at 12 kph
Repeat the sequence 3 times
1 minute at 14 kph
5 minutes at 8 kph

This workout would only take 23 minutes.