Building your aerobic system is vital whether you’re in a highly anaerobic sport such as professional hockey, a long distance marathoner, or an average guy or gal looking to be as healthy as possible. But you have to actually develop this aerobic system, which is not done by pushing your heart rate (HR) to extreme levels and holding it for a prolonged period of time. Actually, you want to keep your HR low – such as the 180-age formula or a Zone 2 or Zone 3 heart rate. (Finding your aerobic training zone is discussed here.) This is how you develop your aerobic base for optimum fat burning, overall health, and eventually a strong anaerobic system.
Those who shun aerobic exercise are missing out on these vital benefits – benefits that will not be achieved by interval training alone. I’ve treated several NHL players who stay strong well into the third period because they have effectively developed their aerobic system – not just by skating hard but by doing some prolonged, low HR workouts. Look at another very anaerobic sport such as boxing. I love to watch Manny Pacquio train and fight. He does some 800 meter repeats but he, like other fighters, go out and run long slow distances, just like Rocky. He’s got a superior aerobic system to get him through twelve rounds of a very anaerobic event. In high school, wrestling was my main sport. For those of you who have wrestled, you’ll probably agree that it’s the most demanding six minutes you’ll even endure. Wrestling is very anaerobic, but lasting six minutes and keeping that anaerobic strength is dependent on a strong aerobic foundation.
The amount of aerobic base you need will be dependent on your sport. If you’re interested in all around fitness then your goal is to develop your aerobic system to the max as well as your anaerobic system. If you’re more of a strength and power athlete, then your aerobic conditioning will not need to be as developed as a long distance runner. This may seem obvious to some, but many fail to realize the importance of aerobic for ALL athletes.
Too Much Aerobic?
Aerobic conditioning is best achieved via long workouts several times a week. To some degree, the more the better, (depending on the aerobic capacity you’re seeking to achieve based upon your sport), as long as it is truly aerobic, and eventually anaerobic endurance is incorporated once the base is built. But can you do too much aerobic? You bet you can. There are two main problems I see with those who overdo true “aerobics.” I’ll point out that overtraining the aerobic system is much less common than overtraining the anaerobic system because most people want to go too hard, too fast, too soon in their exercise program. (I will discuss overtraining more in Part IV.)
First are the people who go way too slow and actually never even get into their aerobic training zone. These people train at or below Zone 1 too often, which is best suited for recovery and super-easy days. Running slowly will increase cardiac efficiency but too slowly has what I all “diminishing returns on your investment” – it will take much longer to achieve the same results than if you were training at faster aerobic levels, if you’re able to achieve them at all. It can take years to develop aerobic efficiency, which is why you see many great long distance athletes peaking in the late 30s. If you’re always walking – that’s great – but eventually you need to walk faster, or up and down some hills, or walk/run.
Second, and more common, are distance training athletes who do way too much aerobic for too long and don’t add in some anaerobic training either via intervals or strength work. They fail to maintain an aerobic/anaerobic balance. I have overtrained aerobically twice (that I know of). The overtraining of the aerobic system comes with symptoms a bit different than those of overtraining the anaerobic system. See signs of symptoms of overtraining. Clinically, the thyroid gland gets run down when there is too much aerobic involvement, as opposed to the adrenal glands taking the hit with too much anaerobic (at least initially). Someone overtraining aerobically will lose some body leanness and muscle mass, they’ll be more mentally fatigued, more physically fatigued, and may have a deep chill – “bones are cold.” Anaerobic overtraining may have similar symptoms but typically results in an injury “that just came out of nowhere” or you “woke up with,” as well as frequent illness/infection or getting a cold that will not remedy easily. Interestingly, rest doesn’t correct this aerobic excess problem but rather some anaerobic activity does. So the prescription is often some hard intervals, hill repeats, and/or strength training to get the individual out of the aerobic excess syndrome. (For the therapists out there and others too, you can read my clinical research paper on evaluating the aerobic and anaerobic system.)
HIIT – High Intensity Interval Training: Good & Evil
I don’t want to call this a fad but it sure does seem to be the new “in workout” though interval training is nothing new. High intensity interval training is basically alternating between a period of high intensity activity, say for 5-60 seconds, and then recovering in-between each set, typically by walking, for a period of time. Yes, these workouts can be very effective at increasing your performance AND your health. They can even increase your aerobic capacity – though they are primarily very anaerobic workouts. Despite the aerobic benefits, continued implementation of these types of workouts over time will break you down; your immune system, your hormonal system – all the systems of your body will all suffer. Additionally, oxidative stress (free radical damage) occurs with anaerobic excess and that can lead to premature aging and many diseases, such as autoimmune diseases and cancer.
These workouts will improve your lactate threshold and even improve how well your body uses glucose in tissues – known as insulin sensitivity. Mitochondria, those energy powerhouses of your cells, are most prevalent in the slow twitch aerobic muscle fibers, but anaerobic training will increase them too – that’s called biogenesis. You’ll also burn fat during these workouts, as well as glucose, and you’ll recruit a high amount of Type II muscle fibers leading to development of your anaerobic endurance. So yeah, high intensity anaerobic intervals are super cool, when you’re ready for them.
Now remember that at low intensity aerobic workouts you’ll burn more fat than glucose but at higher intensity you end up burning more calories over the long run, which can lead to more fat loss. These are all good things, but realize that HIIT workouts, being promoted by some as “the only cardio you need to do” can be very harmful to your health and your fitness if done too often or for some too soon in a training program. Let’s not all forget, especially with the huge focus today on Paleo and the health and lifestyle of our ancestors millions of years ago, we didn’t just sprint, lift, sprint, lift, repeat all day long. Hunter-gatherers traveled across vast areas over time – that’s an aerobic quality. They didn’t run as hard as they could, but they maintained a steady aerobic pace. Look at persistent hunting – one had to be in superb physical conditioning, especially aerobic conditioning, to track an animal for so long, and then utilize the anaerobic system for the sprint in for the final kill (and the throwing of the spear).
Although I feel that a person can begin strength training (discussed next in Part III) relatively early in a training program, HIIT workouts should be excluded from any program until there is a sufficient aerobic base. Unfortunately though, many start these workouts immediately due to time constraints as advocates say they’re “more practical.” It’s a time crunch issue, much like a person looking to take a pill for a quick fix rather than address their health problem. Many people don’t want to, or don’t know how to, develop some aerobic endurance. Many of the studies, such as this one from 2006 in the Journal of Physiology, make special note that HIIT workouts are “time efficient strategies.” That doesn’t mean they should replace all aerobic conditioning workouts. Plus, these studies are short – they’re not following participants for months after the study to see how their health and fitness are progressing. And they’re not advocating they continue in such an exercise fashion either.
HIIT workouts dramatically increase stress hormones, such as cortisol and epinephrine, which over time can lead to health problems and injuries. Low testosterone levels in men and low progesterone levels in women occur from training too hard, too often, with insufficient rest. This can come from too many HIIT workouts or too much high intensity “cardio” as discussed in Part I. True aerobic exercise, however, can not only lower stress hormones but increase anabolic hormones such as testosterone, estrogen, and progesterone. Anaerobic sprints are touted as a great way to increase human growth hormone (HGH), but aerobic exercise, when done properly, won’t deplete it. Excessive anaerobic can deplete growth hormone as much as proper anaerobic can increase it.
Essentially, without a sufficient aerobic base, you’ll overtrain (Part IV). Once you are ready to implement HIIT workouts into your training, you should follow common sense anaerobic guidelines – adequate recovery (often 48 hours in between workouts), and adequate breaks (cycle weeks on/off depending on your program). In other words, you should not be doing HIIT workouts 3-4 times a week for several weeks (5-6+) without a change in intensity or a break, or you’re destined for problems. The amount of HIIT workouts you can handle is determined by your health, recovery, aerobic capacity, and overall stress in your life.
So remember – those who want to talk anti-aerobic are often the same groups that bash long slow distance training and unhealthy looking, muscle-wasted “skinny” runners. If done properly, your aerobic workouts should be relatively not too easy but not too difficult; some say you should finish an aerobic workout “pleasantly tired.” But for many it’s not low intensity because their health and fitness sucks (yeah, it’s true) and they’re impatient to develop their aerobic system. Oddly enough, if you’re in a “time crunch” as most are, HIIT workouts can be one of the worst things for your health, (I underlined that for emphasis). Sure you’ll develop some aerobic and anaerobic conditioning faster than if you just logged in a bunch of miles, but when you’re already producing a lot of stress hormones from being in that “time crunch” and also most likely eating poorly and not sleeping well, more anaerobic activity in your already anaerobic life is not a good thing. It’s a great way to soon be injured or develop some health condition. That’s fitness achieved by compromising health. It’s not just [all] about looking buff. You might not care to run a 10K in 40min but you should be able to run one in roughly one hour – and not all out anaerobic, which an unfit person wouldn’t be able to sustain anyway. To me, that’s a level of fitness. You’re not going to get there doing just speed work.