Building the Aerobic Engine

For running you need to develop the correct system- the aerobic system. This is the highly efficient system utilizing oxygen, glucose, and fat metabolism. The modern analogy is this. Each of us is blessed with a hybrid engine, actually millions of hybrid engines at the muscular level. The electric engine is your fat burning aerobic system- highly efficient and can run all day on minimal added fuel. It is resilient to breaking down. In your body this is fat metabolism at the mitochondrial level of your muscles. The physiology is complex but the practical implications are this. Producing ATP allows muscle contraction. There are two types of metabolism, anaerobic and aerobic, and important varieties of these.

Most understand the anaerobic because they feel it.

• Explosive exercising–sprinting- with pure anaerobic respiration produces 6 to 10 seconds of immediate energy with ATP and Creatine Phosphate in the stored in muscles. No glucose is needed, but contractions stop after 10 seconds.
• If you lower the pace to a hard effort you can sustain for only 1 to 15 minutes or so you are above the anaerobic threshold. This is the glycolytic anaerobic system. You use muscle glycogen and lactate as fuel, but the hydrogen ion waste products produce the toxic acidosis. This too is not efficient for longer distances. You produce only 2 ATP per molecule of glucose.

The aerobic system is where the powerful hybrid engines lie at the muscular level.

• If you lower the pace a bit to an oxygen utilizing zone you get 36-38 ATP per molecule of glucose- this is the gas engine- somewhat efficient as we can store enough glycogen and blood glucose to give 90 minutes or so of activity.
• Now if you slow down a bit more to below the aerobic threshold you can develop the mitochondrial machinery to break down fat into energy. Your efficiency jumps exponentially-460 ATP per fat molecule! This is the electric engine. (Endurance Sports Nutrition p 32). If you have ever driven a Prius, you see the subtle mixing of gas and electric which you cannot detect as the driver. Your body is doing this all the time in exercise. You want more electric! Any activity lasting more than a couple hours is largely electric.

Many of us are running too hard daily and constantly using and replenishing the easily accessed glycogen tank and blood glucose. When blood glucose levels drop we crash. Mind and body sense an overwhelming fatigue. Topping off this tank at high levels of exertion is problematic as we do not feel hungry. Blood is being shunted from the gut to the active muscles. Even if you do force down calories it tends to sit there, or worse toss back up. When this occurs you have options. Walk, shelf the pride, and refill your tank a bit. Or take the more comfortable option and call it a day.

To constantly access the deep fat burning tank you must train correctly. We will teach you how. Some added glucose is still important, but we are most efficient in hybrid mode with the majority of the power coming off electric (fat burning).

So how do you build these mitochondrial factories in your muscles so your hybrid engine is at optimum performance? The analogy is this- your goal is to build a bigger engine- build millions of mitochondrial factories and the capillary blood supply to deliver the oxygen to them. The heart and lungs are the fuel pump, the engine is the millions of fat and glucose burning mitochondria in the muscles.

The good news is that it is all about running easy. For most highly motivated exercisers, the definition of easy is not uniform. What level of effort is easy to build and utilize the aerobic system? How can you assess this yourself?

The pioneer was New Zealand’s Arthur Lydiard who trained the best middle distance and distance runners in the 1960’s. His system is based on months of aerobic training followed by measured increases in intensity as events approach. His principles still apply in almost all modern training. Lydiard’s runners were taught what easy was under the master’s eye. 800 meter specialists were running 22 mile long runs and 100 mile weeks in their base phase- why? To build a massive and resilient aerobic system, on which everything else later would be build upon.

Most of us do not have a master teacher, so how do we learn this pace? The secret is a heart rate monitor. The modern masters of this technique are Lance Armstrong, 6 time Ironman Champ Mark Allen, and British Marathon Legend Priscilla Welch.

Armstrong’s coach Chris Carmichael describes Lance’s training in “The Ultimate Ride”. After his Tour de France recovery, Lance would go into winter/spring aerobic system building setting his aerobic threshold HR at 145- no higher. The aerobic threshold is the fine and mostly undetectable line where you are converting from more efficient fat energy to the more accessible glycogen and glucose energy. The former has limitless supply, the latter good for about 1-2 hours. Paradoxically, training these fat burning engines produces the rich capillary pathways that allow glucose to be used more efficiently too when it is needed during faster running.

Lance rode 1000’s of miles, became leaner, and generated more and more power and efficiency at the low HR. He ate amazingly little before or during his rides, teaching his body to fat burn. When he was no longer improving at the low HR he knew he could build no more “factories”- his electric engine was as large as it could be. It was time now to train the glucose burning (gas) aerobic system and the glycolytic anaerobic system required for sprints, time trials, and breakaways on final mountain climbs. Lance had full access to his “gas” tank for these measured efforts, using his electric engine at all other times. Other riders were not so fortunate and were spent at the time the hard effort was needed.

Another master of this is Mark Allen. He describes his evolution to this method in his website. Mark tried to finish each and every run all out. After seasons of inconsistencies and fatigue, he soon discovered that running harder and harder was not the answer. Convinced though skeptic of Phil Maffetone’s lower effort training he put a heart rate monitor on and at a pace of 8:15 per mile his HR monitor would beep at the preset 155. This was slower than he ever ran. Convinced to take the slow burn approach he took months and ran at 155 HR. During these months he became more efficient and faster at the low heart rate and soon enough he was running effortless 5:30 miles at this easy effort.

Priscilla Welch won the 1987 New York Marathon at age 40, a feat likely never to be repeated. She took up running as recreation in her 30’s. Priscilla was a master of efficiency, with 10k times only a trace faster than her marathon speed. She pioneered the Maximal Aerobic Function Test.

Priscilla was a believer of the powerful feedback of the Heart Rate monitor. In her build up for races she did the bulk of her training below HR 150. She would not exceed this even if it meant walking up a hill. She would judge her fitness not by a “time trail” (all out effort over a distance) but by the Maximal Aerobic Function Test. Her HR was set to go no higher than 150 and she would measure her time over a 5 mile course. She knew she was aerobically fit when she would hit her goal times at the easy effort.

These experienced athletes and coaches also understood that mixing in hard anaerobic work during the aerobic building phase inhibited aerobic development. Many athletes are constantly doing cycles of hard intervals week in week out all year and find themselves fatigued, injured, or lacking the joy in their running. Aerobic running is the happy zone, where the runner’s high exists. Very short 6-10 second sprints can be done in this phase to develop biomechanical efficiency and neuromuscular movement. These short bouts do not produce the damaging acidosis.

So how do you determine what this “go no higher” HR is to maximize fat utilizing aerobic development and all the cellular and vascular changes that occur. Most of us do not sense this until it is too late in our efforts. The high tech way is in an exercise physiology lab. The simpler and more practical way is to apply the Maffetone Method. Phil Maffetone has been the coach and advisor to many world class marathoners and triathletes, as well as thousands of recreational athletes. See the link for a more detailed article but here is his formula:

The 180 Formula

To find your maximum aerobic heart rate:

1. Subtract your age from 180 (180 - age).
2. Modify this number by selecting one of the following categories:
   1. If you have or are recovering from a major illness (heart disease, any operation, any hospital stay) or on any regular medication, subtract 10.
   2. If you have not exercised before, you have exercised but have been injured or are regressing in your running, subtract 5.
   3. If you have been exercising for up to two years with no real problems and have not had colds or flu more than once or twice a year, subtract 0.
   4. If you have been exercising for more than two years without any problems, making progress in competition without injury, add 5.

For example, if you are 30 years old and reasonably fit you would fall into category 2c: 180 - 30 = 150.This is your maximum aerobic heart rate for base training. For efficient base building, you should train at or below this level throughout your base period.

Other good references are Joe Friel’s “Total Heart Rate Training” or Edmund Burke’s “Precision Heart Rate Training”. These two books go into more detail about determining optimum heart rate zones for training and are definitely worth the read. Joe Friel’s web site has some great free resources. The 30 minute test linked under “free resources” and calculating Zone 2 gives the most precise method outside of the fancy exercise physiology lab. Use this documentto find your Zone 2.

To summarize what all this means for you as you start or develop your program.

• For optimum performance it is critical to develop the aerobic system. Most have not fully developed this. This is not “no pain, no gain”, but rather “no pain…thank you”
• A few of us have good cues to what aerobic pace is and can run in this happy and efficient zone without the feedback of a monitor.
• Others of us are more hard chargers and need a feedback tool not to help us speed up, but to slow down.
• It takes months to fully build the aerobic engine. Only then and when your event is nearing is it wise to add speed. Doing speed too early can lead to burn out and injury and inhibit aerobic development. There are no short cuts or six week plans.

Building the Electric Engine. Achieving You Maximal Aerobic Fitness through Proper Heart Rate Training. My example at age 42.

There are many ways to determine your aerobic training zone from a wide variety of methods. I’m going to explain some of the more popular ways of determining your optimal aerobic training zones and give an example for each.

The aerobic training zone is the optimal zone for aerobic development and building the billions of mitochondria, capillaries, and fat burning enzymes to allow for optimal utilization of fat as fuel. This occurs mostly at the muscular level, not in the heart or lungs. Remember each molecule of fat burned produces 460 ATP (energy units) vs. only 36 ATP per molecule of glucose. For most runners this is around 70% - 80% effort….but what does that really mean in numbers. This would be high-Zone 2 according to the zones that Joe Friel uses in Total Heart Rate Training.

In training one might even train at a little lower heart rate just to give some room for cardiac drift (when the heart rates rises at the end of a workout due to fatigue). In order to compare these formulas fairly, I will use my own numbers at 42 yo, running about 50-60 miles a week, no real speed work, and able to run a 2:35 marathon.

Vital Stats:
Age - 42
Max Heart Rate - 190
Resting Heart Rate - 40
Lactate Threshold: 178 (determined by 30 min hard temp run described by Friel)

Key Terms:
HR = Heart Rate
MHR = Maximum Heart Rate
RHR = Resting Heart Rate
HRR = Heart Rate Reserve or number of beats between your RHR (resting heart rate) and your MHR (maximum heart rate)
BPM = (Beats Per Minute)

Age-Adjusted Method
The most commonly known way to determine your training zones. We have all seen this one: This is wrong half the time, but can be a safe start point for a new runner.
220-age = MHR (maximum heart rate)
220-42= 178. 178 x .70 (70% of max) = 125
220-42= 178. 178 x .80 (80% of max) = 142
In this example my Zone 2 aerobic training zones would be from 125-142 BPM.

Karvonen Formula
Another widely accepted method to determine your training zones. It’s a little more complicated:
The formula is: ((MHR- RHR) x 70% intensity) + RHR = Training Zone
190 (my max) - 40 (my RHR) = 150
150 x .70 (70% of max) + 40 (RHR) = 145
190 (my max) - 40 (my RHR) = 150
150 x .80 (80% of max) + 40 (RHR) = 160
In this example my Zone 2 aerobic training zones would be from 145-160 BPM

MAF Method (180 Formula)
This is the method developed by Phil Maffetone. This formula determines your maximum aerobic zone. Athletes such as Mark Allen and Mike Pigg have successfully used this method for base building. This is what I call high end Zone 2.
Take 180 - Age
We need to adjust this number based on your current level of fitness. Make the following correction as it applies to you:

• If you do no working out subtract another 10 beats
• If you workout 1-2 times a week subtract 5 beats
• If you workout 3-4 times a week leave the number as it is.
• If you workout 5 or more times as week and have done so for a year or more, then add an additional 5 beats to that number.

If you are about 60 years old or older OR if you are about 20 years old or younger, add an additional 5 beats to the corrected number you now have.
From these adjustments I calculate the following:
180-42= 138
Adjustments: I work out 5 or more times per week so I will add 5 beats to that number.
Using this method, I end up with a maximum aerobic zone of 143

Freil Method (based on Lactate Threshold) Using the protocol in the Triathlete’s Training Bible and from my own personal LTHR tests, I calculated my run Lactate Threshold to be 178. From here I can calculate my Zone 2 ranges. Friel uses the range of 85-89% of LTHR vs. any MHR formula.
178 x .85 (85 % of LT) = 151
178 x .90 (90 % of LT) = 160