There are moments of incompetence that stand out in everyone's life. Whether personal or professional, these failings often serve as a stern slap in the face that redirects your attention toward the neglected aspects of your development. I experienced such a moment last month when, after casually running the two blocks home from work, I found myself pausing on the front stoop to catch my breath.
That's right – me, a person whose job it is to help people get in shape – was momentarily humbled by a breezy, 90-second jog. I confess to this humiliation as an act of contrition, but also to illustrate just how far out of focus traditional aerobic exercise has fallen among fitness professionals and enthusiasts alike. Depending on who you ask, the running industry is either on life support (thanks, millennials) or experiencing a rebirth (thanks, millennials).
I train with a serious and focused effort four days a week. Very little of that time – those rare occasions when I warm up on an elliptical machine – is devoted to any form of slow-and-steady cardiovascular exercise. Ask most lifters and chances are good they spend as little time developing their aerobic fitness as I do. After all, if your goal is a three-plate squat (315 pounds) and a set of traps that would make Brock Lesnar envious, well, jogging ain't going to get you there. The problem is, there are major health benefits to traditional cardio exercise that resistance training doesn't provide, benefits that don't always reflect in the mirror.
A tale of two energy systems
Cardiovascular exercise (or "cardio," in gym-speak) is any physical activity that's performed in a rhythmic manner and that raises your heart rate above resting levels for a sustained period of time. There are two types of cardio exercise, each named for the energy system that fuels them: aerobic and anaerobic. Aerobic exercise is moderately paced, requires oxygen to produce energy, and can, in theory anyway, last for a long time. Anaerobic exercise, by contrast, is highly intense and takes place in the absence of oxygen, meaning you've only got a handful of seconds before you crash.
A leisurely 5-kilometre run utilizes the aerobic energy system. Sprinting after the streetcar as it closes in on your stop? That's the anaerobic energy system. It's the intensity and duration of the exercise that differentiates the two forms of exercise, though the line that separates them can become blurred. Once that sprint slows to a trot, you're in the aerobic zone, and vice versa.
The benefits of cardio
The Canadian Society of Exercise Physiologists (CSEP) recommends that adults between the ages of 18 to 64 accumulate at least 150 minutes of moderate-to-vigorous-intensity aerobic exercise each week, in bouts of no less than 10 minutes at a time. The benefits of this sort of regimen are well-documented: reduced risk of heart disease, stroke, type 2 diabetes, not to mention its powerful positive impact on mental health.
Studies have shown that anaerobic exercise (of which lifting weights can be classified, so long as the intensity is high enough) can be just as beneficial for heart health, plus anaerobic exercise helps to build lean muscle mass in a way that aerobic exercise can't. This is why veteran gym rat meatheads such as me shun jogging, opting instead for hill sprints and kettlebell circuits.
Now you may be wondering, if both methods of cardio training provide similar payoffs, does it matter which one you choose? Yes and no. A good personal trainer wants their clients to reap the the most reward in the least amount of time. Putting you on a cardio machine for 30 minutes doesn't meet that standard. Plus, it's boring for the both of us. This is why high-intensity interval training (HIIT) is so popular with personal trainers – it's engaging, efficient and it works.
The drawback? Anaerobic training is hard! It takes a lot of mental fortitude and a fair amount of skill to make it through 10 minutes of all-out effort in the gym. Having someone who's obese or recovering from a heart attack engage in HIIT is not only counterproductive (they will hate both it and you), it's dangerous and irresponsible.
My recommendation is that newbies focus on resistance training and developing a solid foundation of aerobic fitness before venturing into the world of intense anaerobic exercise. And even then, once you've built your aerobic capacity to a sufficient level, don't turn your back on the treadmill lest you find yourself, like me, gassed from a simple run home after work. Unless you're a junkie who needs their fix on a daily basis, 15 to 20 minutes of cardio training three times per week should suffice.