HIT is all the rage. And why shouldn’t it be? It advertises the same health benefits of a long workout, in a shorter period of time. HIT taps into our need for instant gratification; we think we’re going to get the results of doing more work, without actually doing more work.
Even coaches who I used to respect are jumping on the HIT bandwagon to get followers. It has become trendy for authors trying to be popular to bash aerobic training by making claims that you will get fat and lose strength, power, and muscle. By reading this rubbish, you would be under the impression that the only people that need aerobic training are triathletes and marathoners, or people who want a body like one. Or that standard aerobic training requires you to run or cycle for hours on end. And you would be completely wrong.
Not only does the crusade against aerobic training show a lack of understanding of energy systems and athletic performance, it also is detrimental to those who need the right kind of aerobic exercise, and struggle to enjoy other types of fitness.
Mr. Ace was my PE teacher in high school. He had a big mustache, wore white tight shorts, and was something of a ladies’ man. But the one thing he knew about was health and fitness. He was a big advocate of early nights, lots of veggies, and aerobic training, Mr. Ace had it right. Aerobic exercise is where it is at.
The Skinny on Energy Systems
Many people incorrectly consider sports like MMA or boxing to be “anaerobic,” despite the fact that they can last for well over 30 minutes. But with that misconception, it’s easy to see how many coaches and fighters could become disciples of the church of HIT. This is reinforced by the marketing for HIT, which would have you think that aerobic exercise is best left for Jane-Fonda-style aerobics classes. But if you have had the good fortune of reading Joel Jamieson’s Ultimate MMA Conditioning or any of his online material, you would know that training the aerobic system is the most important, as it underpins everything else.
The fuel that your body uses to supply your muscles is called adenosine triphosphate (ATP), which could be thought of an energy currency for your body. Through a chemical reaction that breaks down ATP into smaller molecules (ADP +P), energy is released.
There are two anaerobic systems that your body uses to produce ATP without the use of oxygen:
- Alactic – 10-12s of powerful energy production
- Lactic – 60-90s of powerful energy production
The downside of the anaerobic systems is they can only do this for a short period of time before fatigue kicks in. The use of this high-powered system comes at a high price, and the more you rely on it, the faster you will start to gas.
The aerobic energy system, on the other hand, relies on oxygen for ATP regeneration. It is not capable of the same swift energy production as the anaerobic systems, but it can produce energy for long periods of time without too much fatigue. This means any sport that lasts more than a few minutes (read: nearly all of them) relies on aerobic energy production. It is also the system you rely on to fuel your muscles and vital organs in everyday activities and at rest.
Here’s the clincher: Aside from providing the majority of the ATP that your muscles need (even through a typical MMA fight), the aerobic system also refuels the anaerobic systems so that they can fire up again. That’s right—the better you train the aerobic system, the quicker your alactic and lactic systems can recover. The more you use the anaerobic systems the more metabolic byproducts you also produce, and the faster you “gas out.” The body relies on the aerobic system to remove these products and restock ATP. So without a well-developed aerobic system, the body’s anaerobic systems are also limited, because it takes it much longer to produce energy again.
The Aerobic System and Sport
If we are looking to improve aerobic power for sports and get better conditioning, we need to raise the threshold at which the body begins to fatigue, when anaerobic processes start to come increasingly into play. The longer you can delay this from happening, the less likely you will be to gas out. If we train the aerobic system more effectively, we can delay this onset, effectively raising what is called your anaerobic threshold. To put it simply, the better your aerobic system, the higher your anaerobic threshold.
Endurance athletes rarely have to tap into their anaerobic system to generate the energy they need. Much less energy needs to come from the anaerobic system if the aerobic system is producing more power. Many pugilists or athletes in general lack conditioning because their aerobic system has never been developed well, and it’s just not capable of generating enough energy or power. They are left to rely on the anaerobic systems too much. The irony is, when we look specifically at the great fighters over the years, they have always organically known this and have been doing road work since the beginning.
HIT, Aerobic Training, and the Heart Health Crisis
Cardiovascular disease is the number one killer worldwide. As the fitness industry continues to worship at the church of high intensity training, fewer people invest the time and effort in steady state training. This is disastrous, as it is one of the things that can really make a big impact on cardiovascular health. In fact, some studies showed that moderate intensity continuous training (MICT) led to greater reductions in bodyweight and heart rate than HIT, which is vitally important for cardiovascular disease sufferers.
Higher intensity training is advantageous for more athletic individuals who have a smaller adaptive response window, but present research suggests that there is little unique advantage to HIIT protocols with minimally trained individuals. Further, given that the enjoyment of the highest intensity protocols is lower, it seems reasonable to suggest that long-term adherence to this form of training may not be great. The only training that works is the one you stick to.
When you do low intensity work (often noted as 120-150 beats per minute), you allow a maximal amount of blood to profuse into the left ventricle of your heart. As you force blood into that left ventricle, it’s in there just long enough to stretch the heart walls. Over time, this creates an adaptation: your left ventricle stretches and gets wider. This is called eccentric cardiac hypertrophy, and it differs immensely from concentric cardiac hypertrophy, where the walls of the heart increase in size and get thicker from the higher blood pressure of strength training, wrestling, etc.
When you stretch that heart wall as in ECH, you can get more blood in and out with each heartbeat. The technical term for this is stroke volume (SV), or the amount of blood you’re moving with each beat. All this makes your heart more efficient. If you can move more blood with each heartbeat, your heart doesn’t have to beat as fast. Training at lower intensities increases stroke volume and decreases resting heart rate.
Many people make the mistake of thinking that if they work harder and faster for shorter, it will have the same effect. It doesn’t. Once your heart goes above a certain threshold, the contractions become too fast for the chambers of the heart to fill all the way. The result is that you don’t get the same adaptation.
The development of an endurance-trained heart and a strength-trained heart should not be considered an absolute concept. Both strength training and endurance training cause left ventricular hypertrophy, but left ventricular wall thickness is found to be higher in strength training, while dilatation of the left ventricle is a prominent feature of endurance-trained hearts.
Don’t Forget the Nervous System
Heart rate variability (HRV) can be an amazing tool not only to measure recovery, but also overall heart health. HRV is very closely tied into the ANS. The two branches of the ANS are the sympathetic (fight or flight) and parasympathetic (rest and digest) systems. As you can appreciate, it’s not healthy to be in either one of those states all the time. Some stress is healthy, too much is not.
You tap into your sympathetic nervous system while you’re training or doing HIT, but you shouldn’t be living in that system all the time. Every workout you do shouldn’t place you in flight or fight mode because it so hard. Doing so will hinder recovery and affect your ability to sleep, and maybe steer you in the direction of overtraining or even adrenal fatigue. Considering so many people have health problems associated with a lack of sleep, hormonal imbalances, chronic stress, and inflammation, you can see why doing a heap of HIT isn’t such a great idea. There needs to be balance.
How to Do Aerobic Training Right
One of the best ways to train for these adaptations is cardiac output training (CO). If your resting heart rate is in the 60s or 70s, if you are new to fitness or short on time, then CO training is where you should look to focus. Look to train at between 120-150 beats per minute (yes, that low), a few times per week, for a minimum of 30 minutes, preferably 45-90 minutes. Some ways to do this are jogging, swimming, rowing, cycling, basic calisthenics, drills, footwork, shadow boxing, and basic MA and MMA techniques, so you can keep your heart rate in the right zone.
Like all fads and trends in the fitness industry, hopefully, the anti-aerobic training one will disappear soon. Aerobic exercise isn’t the devil. For most sports, you must invest considerably in your aerobic development (while training the others systems too) if you want to perform well. And if you want to reduce your chances of cardiovascular disease to stay on this planet a little longer, I’d seriously reconsider your use of time and prioritize your aerobic health first.