Why exercise for more than 10 to 20 minutes at maximum intensity (AMRAP, for time!) when CrossFit tells you that’s all you need? Why work out for more than seven minutes when “science” says that 11 percent of an hour, and 4 percent of the week, did the job just fine? In fact, for the Tabata set out there, why waste any more time that four minutes or less of 20-second intervals?
I could easily go on. Very short, high-intensity workouts are in — like really in — and in fact they’re even hotter than Hansel right now. These workouts all share similar features:
1. They are very short in duration: anywhere from four minutes to 20 minutes.
2. They are either interval-based or based on workout density (doing as much work as possible, in as little time as possible).
3. They are all intended to be performed at maximum intensity, meaning your heart rate should/will be working at over 85 percent of your maximum heart rate during the workout.
They are also incredibly one-dimensional, with a focus that eschews lower intensity work, for longer durations of time, that could be pretty darn beneficial, if not absolutely vital, to your development of optimal and balanced fitness. They in fact create a polarity between what is now thought of as “old school cardio” and the new school of short, dense, maximum intensity workouts.
Let’s face it: Aerobic “steady-state cardio” (e.g. easy jogging) is as in-fashion as Z. Cavaricci’s — those of a certain age will remember those — or, for the younger set, a trucker hat.
The problem is there is less a polarity between the old school and new school, an “either or,” and more so a “this and” when it comes to developing balanced, optimal fitness.
The idea that working out at a high intensity will lead to better fitness, whether for fat loss or performance, has merit — but too often today, we see it applied incorrectly. The shift toward high-intensity training has been so strong that many are even doing it exclusively and vilifying more traditional forms of cardio and weight-training. No other form of exercise has been thrown under the bus more than low-intensity, steady-state aerobic exercise. When was the last time you went for a walk in the park, climbed a few hills on a hike or even lightly jogged on the treadmill, and counted that as a workout? Was there anything wrong with it in the first place?
In the past and even today, traditional cardio has also been used incorrectly. Look no further than the person you see at your local gym who jogs on the treadmill every day for an hour, and doesn’t do anything else. Perhaps the extreme shift toward high-intensity training was a response to this kind of training. No matter what was responsible for this swing to the opposing end of the spectrum, it’s time to find a better balance. It’s time to shift the pendulum back to the middle.
A Brief Explanation of Energy Systems
I hear the word “cardio” slung around as an all-inclusive term to mean anything from walking to sprinting — heck, even some powerlifters define cardio as a set of squats with more than five reps! Most folks use “cardio” a catch-all to mean anything that gets you breathing heavier and your heart pumping faster. Using it as a catch-all is problematic, however. Whereas many different activities may elevate our heart rate and increase respiration, thereby developing CARDIO-pulmonary fitness (essentially improving the health and performance of your heart and lungs), lumping it all into the same category is an issue. The same is true of relegating “cardio” to only mean longer, slower, lower-threshold exercise.
One way to think about this is considering the phrase “I spent money.” Did you use a check, credit card or cash? Or was it a combination of two or all three of these monetary instruments? Simply saying “I spent money” doesn’t tell us anything about where the resources were pulled from.
The same is true of the energy systems that fuel our body.
For purposes of simplicity, we essentially have three energy systems to fuel activities of varying lengths and intensities:
1. Short burst/high intensity (anaerobic);
2. Middle-range/moderate intensity (glycolytic); and
3. Longer duration/low intensity (aerobic).
These three sources do not work exclusively, for the most part, but rather as a blend of varying percentages that we draw on when performing varying activities. Using the spending analogy above, this means that sometimes we may pay using 80 percent cash, 10 percent credit card and 10 percent check; while other times we may pay by 10 percent cash, 50 percent credit card and 40 percent check.
An entire book could be written on the above, and in fact several have been, but for the purposes of this article and not making your head spin (not to mention saving your training!) I will focus on why you need to stop skimping on longer duration, lower intensity aerobic exercise.
Without further ado, and with the caveat that it’s about to get nerdy up in here, here are four reasons why:
1. Aerobic capacity.
For most gym-goers, a good training program should include work of both low and high intensity. Do one or the other, which seems to be the norm, and results may be less than ideal. Generally speaking, when we work out at a high intensity — short, powerful activities such as sprinting or lifting heavy weights — we tap into our anaerobic metabolism, which is not oxygen-dependent and great at producing energy in short bursts. The opposite is true when we work out at a low intensity; we tap into aerobic metabolism, which is oxygen-dependent and better at producing stable energy over a long period of time.
This capacity for aerobic metabolism is important. Research has actually shown that better aerobic capacity enhances our high-intensity training pursuits. Have you ever tapped out during high-intensity interval sprints? Better aerobic capacity allows us to delay the onset of anaerobic metabolism and the physiological processes associated with it, including the activation of your body’s stress system (the sympathetic nervous system). Since anaerobic metabolism gets capped pretty fast, this means aerobic capacity allows us to save it for when we need it most — those last few sprints in the interval. Low-intensity aerobic exercise is a great way to develop this aerobic capacity.
2. Recovery.
Along these lines, low-intensity aerobic exercise has also been found to have beneficial effects on markers of recovery in the human body. Research has shown that having good aerobic fitness enhances recovery from bouts of high-intensity exercise and delayed-onset muscle soreness, the hallmark of heavy strength training. Furthermore, how fast does your heart beat during high intensity exercise? Aerobic exercise increases heart rate variability, which measures how quickly your body switches back from an elevated heart rate brought on by the stress system to a normal heart rate modulated by the resting system (the parasympathetic nervous system). Low-intensity aerobic exercise increases this parasympathetic activity, which decreases our heart rate at rest and helps us sleep and recover better for the workouts we have ahead of us.
3. Fat loss.
In the gym, we often see people who just lift weights, or just do cardio. Just as a good training program should include both low- and high-intensity work, it should also contain a mixture of both weight training and aerobic exercise. Taking this even further, there’s a growing body of research focused on the efficacy of concurrent training, which combines the two modalities in one workout. This research has shown that strength training and low-intensity aerobic exercise can in fact go together. In these studies, concurrent training has been found to increase lean body mass, decrease body fat and have positive effects on markers of obesity, such as abdominal fat mass and waist circumference. Often, these results were better than those achieved by either strength training or aerobic exercise alone.
4. Mental health.
Finally and perhaps most importantly, the effects that low-intensity aerobic exercise has on mental health cannot be understated. Exercise is effective as an antidepressant and can alleviate symptoms of depression. Recent research has demonstrated that people with depression or anxiety disorder have low levels of physical activity and sedentary lifestyles. Though it’s widely accepted that any form of exercise is good for mental health, for those who have not exercised regularly and are sedentary, low-intensity aerobic exercise might be the easiest and safest way to start. In fact, low-intensity aerobic exercise has very recently been found to be a great addition to cognitive behavioral therapy for people with panic disorder. Thus, if you need something to ease your nerves, it might not be a bad idea to turn to some aerobic exercise.
So, in a nutshell: If you want to be a healthy, happy, fast-recovering, ripped, high-intensity machine, don’t skip slow, low-intensity exercise.
It’s time to bring low-intensity, steady-state aerobic exercise back into the fold, just like the trucker hat. (No, not like the trucker hat actually. But maybe like hand-written thank you notes.) It was never a good idea to just do high-intensity interval training, nor was doing just “cardio.” Aerobic exercise has potent effects on your training capacity, recovery, body composition and mental health, and it would be unwise to omit it. Now get up and go “beast mode” on that walk.
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Cardio Isn’t Dead Yet originally appeared on usnews.com
