Have you ever finished a workout that really got your heart rate up and said, "That was hard!"? While not every workout should be a killer, heart-racing bout of exercise, a recent study shows that regular high intensity cardio intervals combined with shorter rest intervals significantly improve fitness.  A recent University of Copenhagen study published in the Journal of Applied Physiology showed that runners were able to improve their cardiovascular fitness, despite significantly reducing the amount of training they did (by about 50%!).

The runners were all moderately trained (not elite) and followed a 10-20-30 training concept developed by the University's Department of Exercise and Sports Sciences. According to SceinceDaily.com, "The 10-20-30 training concept consists of a 1-km warm-up at a low intensity followed by 3-4 blocks of 5 minutes running interspersed by 2 minutes of rest. Each block consists of 5 consecutive 1-minute intervals divided into 30, 20 and 10 seconds of running at a low, moderate and near maximal intensity, respectively." After seven weeks of training, runners improved their 1km (.62 miles) time by 23 seconds and 5k time by one minute. That's huge! Reading through the way the 10-20-30 training concept may sound a bit complicated, but in a nutshell,  heart rates were brought to near max and then brought them back down again. This was repeated over and over again for about 30 minutes.

Just as significant was the improvement in other areas of the participants' health. Blood pressure was reduced and cholesterol dropped.

The "less is more" notion of interval workouts is nothing new. I'm a big proponent of quality of exercise versus quantity for the everyday fitness enthusiast. That is, people a lot like you and me who probably aren't going to turn pro anytime soon, and are just exercising to stay fit. There are some exceptions, of course. Try telling an Ironman amateur athlete that he or she only needs to do 30 minutes of daily training to improve fitness and you'll probably see their eyes roll to the back of their head.

A lot of people have a hard time embracing this concept because they're concerned about not burning enough calories or fat in just 30 minutes. Here's the deal...it's true, while you're working out during those 30 minutes you won't burn as many calories as you would if you worked out for 60 minutes. However, after about 15 minutes of slow, steady exercise, your cortisol actually starts to elevate. When cortisol elevates, your body decides to burn muscle, not fat. Week after week of this type of training will result in a slower metabolism because you've just lost valuable muscle. On the flip side, when you pepper in a series of very high intensity cardio intervals, your body will burn fat - and then continue burning fat long after the workout has ended. Cortisol doesn't have a chance to catch up because you're relaxing the body with rest intervals (dropping heart rates). What's more, you'll maintain or increase your muscle mass.

The bottom line is you should enjoy what you do when you're working out. If that means running an hour a day because it helps clear your head, then keep doing it. It's also important to balance your exercises. Doing the same thing day after day can lead to overuse problems, resulting in injury. Shake things up by adding in yoga, pilates, various forms of weight training or some alternatives to cardio training.  That said, if your goal for working out is to see fat loss and improved muscle mass, consider interval training.

My ebook, 20 High Energy Workouts is filled with interval-only workouts scalable to any fitness level. Why not download it and give a few workouts a try? If you want something more hands on, my 40-Day Shape Up will be open for business next week!


Want more tips like this? Hang out with me on Facebook. I’ll be posting some really great health and fitness tips over the next few weeks, and I don’t want you to miss out. See you there. Traci



University of Copenhagen (2012, May 31). Runners can improve health and performance with less training, study shows. ScienceDaily. Retrieved May 31, 2012, from http://www.sciencedaily.com­/releases/2012/05/120531102205.htm