How much time do you spend doing "cardio"? Do you make sure to get your 30 minutes in on the treadmill, elliptical, or exercise bike each day? Most people who do this eventually hit a plateau. Let me explain why.
The Problems with Traditional Cardio
There are several issues I have with prescribing traditional cardio to my clients. First off, let me be clear: in no way am I saying that inactivity is better than activity. In general it's much healthier to plan active habits into your day as opposed to inactive habits.
However, not all forms of activity are created equal. I'm a fan of both ends of the intensity spectrum, but not the middle. In other words, I urge people to walk as much as possible and even sprint once in a while if they can, but I never recommend jogging for the sake of burning calories. Why is that you ask? The answer...
Poor Muscle Retention
Jogging, as well as other forms of activity in the middle of the intensity spectrum, can be quite catabolic.
Catabolism, or the breakdown of tissue, can be a fantastic thing if the tissue being broken down is fat. However, when muscle is getting broken down as well, as is the case with most mid-intensity activities, catabolism isn't so great.
Muscle tissue is a sign of youth, it burns roughly 4 times as many calories as fat when at rest, and it improves your ability to process carbohydrates. To summarize, you want to keep as much muscle mass as you can! Anything that breaks down muscle tissue should be avoided like the plague.
Thus, a wise fitness enthusiast should stick to low-intensity activities that are "too easy" to be catabolic, or high-intensity activities that are hard enough that they are anabolic. That is, they stimulate the growth of tissue (muscle in this case).
Lack of Effective Progression
Another problem I have with traditional cardio is the fact that, as you do it more and more, you get better at it. If you run a mile every other day for just a few weeks, you'll burn less calories running it in the last week than you did the first time, even if you ran it a bit faster than the first time!
As your fitness increases, the efficacy of mid-intensity cardio decreases. You're going to have to 1) go further/longer or 2) go harder/faster in order to even maintain the same level of caloric burn you started with.
Going longer or further just increases the time investment, so that's not an effective long-term strategy. On the other hand, if you continue to go harder or faster, you soon won't be in the mid-intensity range anymore. In fact, you'll end up in the range that I recommend and that I'm here to talk about: the high-intensity range. So why not start there in the first place?
Enter High Intensity Interval Training
High intensity interval training (HIIT) is technically a type of "cardio" since it successfully gives the heart a great workout, but it is much more challenging than traditional, mid-intensity cardio.
HIIT involves performing an activity, running for example, at a near-maximal pace for a predetermined amount of time, and then "resting" by running at a slower pace. Sprinting for 10 seconds and resting the remainder of the minute is a good example of this.
Multiple activities lend themselves well to HIIT, but some are much more challenging than others. If on an exercise bike, 10 seconds of maximum effort could be alternated with 15-20 seconds of easy pedaling, while running as fast as possible for 10 seconds would require a much longer rest than 20 seconds, assuming you're planning to repeat the cycle again.
In general, HIIT workouts should be intense enough that 20 minutes would be nearly impossible to complete. An effective HIIT workout can be completed in 10 minutes, with 10-15 minutes being a good range to shoot for.
Although 10-15 minutes doesn't seem like much, you'll burn far more calories in that time than you would with 30-45 minutes of traditional cardio. Faster results in less time. It's a win-win! The only downside? You have to work harder. But believe me... it's well worth the effort.
For those of you who want to decrease your cardio time by 50% or more while getting better results, here are some examples of high intensity interval training workouts. Try them out, but feel free to tweak the work:rest ratio to suit your current fitness level.
Running on a treadmill
15 seconds as fast as you can, 30 seconds light jog or walk
Repeat for 8-10 rounds
Running on a track*
10 second sprint, 50 seconds walk or jog
Repeat for 8-10 rounds
*I find it's easier to get to and maintain top speed on a track as opposed to a treadmill, which will be harder and require a shorter work period and longer rest period.
Rowing Machine/Exercise Bike
20 seconds as hard as you can, 30 seconds light and easy
Repeat for 10-12 rounds
Give some of these example workouts a try, and you'll soon see that total time spent working out isn't nearly as important as the effort you put in. Good luck!