“The most common cause of reduced aerobic function is anaerobic training, and/or too much racing. “ Dr. Philip Maffetone, The Big Book of Endurance Training and Racing
The body is an amazing machine, capable of incredible feats of performance. Of the things that set us apart from the other members of the animal kingdom, however, perhaps the most powerful is our aerobic capacity and the way we shed excess heat.
While many animals are faster than us in a short race, eventually a human will catch them. Herd animals such as buffalo or antelope, early food choices for us as a species, cannot sweat. At some point, after running for a while, the animal must make a choice to either stand still – so it can pant and rid excess heat build-up, but also risk capture – or die from heat stroke. Meanwhile we humans will be chugging away remorselessly, sweating freely, and closing in for the kill.
In longer efforts such as events that last for two hours or more, ninety-nine percent of effort comes from the aerobic system. Of our three energy systems this one often seems to get short changed in terms of respect.
A very quick overview of the energy systems goes like this:
- Our first five to ten seconds is powered by the ATP/CP system.
- Once we have exhausted that supply we move to the lactate system.
- After a period of up to two minutes we will no longer be able to sustain that kind of effort and the aerobic system becomes more dominant. The longer the effort the more dominant the aerobic system is.
Some sports, such as boxing, with a championship fight lasting up to forty-seven minutes (twelve three-minute rounds with eleven one-minute breaks) have a varying mix of effort in them, from all out flurries of punches to periods of total rest in between rounds. However, the heart clearly is elevated above rest during the entire match and therefore the aerobic system needs to be strong and robust to cope with this. A thirty-minute event is still ninety-five percent aerobic.
Fat is the main ingredient in powering our aerobic system and is the reason why we’re covered in it. Most of our day is spent at relatively low intensity and right now as you read this you are working aerobically. The stronger your aerobic engine the more able you are to use fat for fuel instead of sugar (called glycogen when used in muscles).
And here’s where it gets interesting.
When your aerobic system is weak, you require more of your energy supply to come from sugar. But when you eat sugar you increase insulin production, which prevents you from breaking down fat to use for energy. To combat this you’ll need more sugar because you can’t use fat. This will increase insulin even more and turn your fat burning ability off even further.
If you’re one of those people who say, “Oh, I did tons of cardio and it just made me fat,” I’m going to say you’re doing it wrong. Most likely you found that you needed to eat more once you started burning up a ton of energy on long runs or rides. That’s okay. If you burn it, you need to replace it.
But, if you start to think, “Well, running is cardio and cardio means I need carbs,” then you’re going to have a problem. Especially if you eat a carb rich meal before your training session. All that does is encourage your body to need sugar during training and switch off that fat burning mechanism. Then you’ll need sugar during the session to fuel it, sugar after to replace what you burnt, and on and on.
I’ll make a bet with you right now that you are far weaker aerobically than you realize. The side effects of being deficient aerobically are as follows:
- Fatigue – The most common symptom is the need for sugar to maintain function. Even just sitting still. Ever wondered why you feel the need to reach for chocolate mid-afternoon? You’ve stopped burning fat effectively and need to get into sugar burning mode.
- Increased body fat – Commonly caused by increasing carbohydrates in the diet.
- Chronic inflammation – Can trigger injuries and ill health.
- Physical injuries – The structures that support our movement, the slow twitch stabilizing muscles, the ligaments and tendons are all fed by our aerobic system.
- Hormonal imbalances – Most commonly seen as high levels of cortisol and low levels of DHEA. The signals for these are cravings for sugary foods, insomnia, and high levels of body fat.
- Reduced performance – Seen as fatigue, loss of speed, and general overtraining.
How can we tell when we have over stepped our aerobic system and have started training anaerobically? It’s quite easy, although many of you will look for ways to wiggle out of this. Before you stop and say something about how special you are or how unique or talented, just remember this formula comes from Dr. Phil Maffetone, the father of heart rate training. He’s been studying this for over forty years and has coached greats like Mark Allen, Mike Pigg, Chris McCormack, Craig Alexander, and Gordy Byrn. This formula has been proven time and time again in elite endurance events. Keep that in mind as you get your fingers ready to type an ill-conceived comeback at the bottom of this page.
Your maximum aerobic heart rate is 180 minus your age. Mine is 140. Above this I am working anaerobically, putting myself in sugar burning mode, and starting the chain reaction of events that will lead to all the signs shown above.
Here are the rules, taken from Maffetone’s Big Book of Endurance Training and Racing:
1. Subtract your age from 180.
2. Modify this number by selecting from among the following categories the one that best matches your fitness and health profile:
- If you have or are recovering from a major illness (heart disease any operation or hospital stay, etc.) or are on any regular medication, subtract an additional 10.
- If you are injured, have regressed in training or competition, get more than two colds or bouts of flu per year, have allergies or asthma, or if you have been inconsistent or are just getting back into training, subtract an additional 5.
- If you have been training consistently (at least four times per week) for up to two years without any of the problems just mentioned, keep the number (180 – age) the same.
- If you have been training for more than two years without any of the problems listed above, and have made progress in competition without injury, add 5.
I will make these three bets with you:
- I’ll bet right now that very few readers will have been sick less than twice in the last twelve months. I am literally the only person I know who can honestly say that (not because I’m a stud, but because clients don’t come train while sick so I am rarely in contact with sick people).
- I will further bet you that if you strap on a heart rate monitor and go for a run around the block you will be appalled at how slowly you need to go to stay under this aerobic cap. Many of you will need to slow down to a walk even on flat and almost certainly on anything even slightly resembling a hill.
- My final bet is this: Stick to the formula, run, ride, and swim easy for a period of six months. Notice the changes in body composition, energy levels, lack of injuries and illness, and even a change in sex drive, then go for a hard effort and see how much faster you are. I’ll bet it’s faster than ever before and all without stress or injury.
Post your heart rate and your starting run observations below and let’s see what the effects are over time.