by Chad Kerksick PhD January 17, 2012 3 min read
Imagine being able to exercise with only 10% of the amount of work as someone else and achieve the same amount of beneficial change to your body. It almost sounds like a gimmick or something you would see on a late night television commercial. These results aren’t a gimmick and in fact a number of published studies have routinely shown these results to occur. Still looking for a catch, a but, or what if? Well, there is one and the catch is that you have to work pretty darn hard during this reduced amount of time to get these results. In this study, scientists had active but untrained college-aged male and female subjects over a 6 week period complete either standard endurance training or high-intensity interval training (Burgomaster 2008). The traditional endurance training group had subjects complete cycling at a difficulty level that resulted in them exercising around 65% of their maximal capacity for 40 – 60 minutes each workout, 5 days per week. This group was compared to another that had its participants complete 4 – 6 reps of an all-out sprint on an exercise cycle for 30 seconds. Each sprint used an amount of resistance that was relative to the person’s body mass. Between each sprint, the participants rested for 4.5 minutes. So for every 5 minute period, the participants in this group sprinted for only 30 seconds of it and during the other time they performed very light cycling exercise. The weekly time commitment including the very long rest periods was 1.5 hours for the interval group and 4.5 hours each week for the traditional exercise group; this value is three times greater than the other. While I’m likely not the physical specimens as some of you who may read these articles, I can assure a 30 second ‘all-out’ sprint on a resisted cycle is not easy. The last 10 seconds literally feels like minutes as your legs and lungs begin to scream.
Despite these substantial differences, each group achieved similar improvements in several markers inside their muscle that was reflective of carbohydrate breakdown and fat breakdown and each group experienced similar changes in how their body utilized each of these nutrients. These results are fascinating when you consider the amount of time devoted to their exercise regimens, respectively. So for all of you who think you have to pound it out on the treadmill or cycle for hours each day, this study and others certainly suggest otherwise. One key point, however, needs to be discussed and that is the overall lack of practicality that exists from this suggested form of training.
For starters, the subjects in this study were healthy men and women in their early 20s. I think we all agree we aren’t nearly as well built as we were when we were in our early 20s. If you are in your early 20s then thank your lucky stars and enjoy it! When considering this point, the exercise regimen is very challenging and something that most people simply won’t do. For a majority of people just getting to the gym and raising your heart rate 40 – 50 beats above your resting values is enough of a workout and sadly for many more, it’s too much to ask. To think untrained, overweight people are going to complete this type of exercise is a stretch. I focus particularly on attempting to make practical suggestions from scientific studies and in this instance the message is simple. Workouts which contain multiple repetitions of hard intervals for short periods of time followed by a longer rest stimulate adaptations which are similar to workouts which require longer workout bouts at a lower intensity. Therefore, if you are strapped for time and want to achieve some sound benefit, then crank up the intensity and do some short intervals. Another suggestion to heed these outcomes is when you start to grow weary of your daily or weekly grind on your cardio workout. Instead, do some intervals for some variety, but be careful and progressively build you up to harder and longer intervals.