How to Dramatically Improve Your Fitness and Metabolism

(through low-intensity exercise aka zone 2, aerobic base training )

As a lifetime swimmer, weight training enthusiast, and youngest brother of three, I have learned a lot through sports, fitness, and brotherly competition- and admittedly have a high level of cardiovascular fitness. Until two years ago, I believed that the key to getting in shape was by working at 90-100% effort for every workout. Whether it was a run, swim, or weight lifting session with my brothers, my goal was to push myself as hard as humanly possible and leave nothing on the table by the end of a workout. No pain, no gain, right?

I was wrong. While this tactic worked for the earlier part of my career, my fitness seemed to plateau, and I was getting burnt out. I couldn’t quite figure out why… until I came across two new ideas that challenged my whole perception of how to get in shape. In this guide to cardio, I’ll explain a better approach.

 

1. The 80/20 Rule

Athletes should spend about 80% of their cardio each week training aerobically (lower intensity) and only 20% in an anaerobic state (higher intensity). For instance, if you run 5 hours a week, about 4 of those hours should be low/moderate intensity. This ratio was almost the exact opposite of what I was doing.

2. Stop huffing and puffing through your mouth.

Breathe calmly through the nose while doing cardio- and it will improve cardiovascular efficiency and health outcomes.

While neither of these ideas made sense to me (how could I get in better shape if I wasn’t training hard every workout?), I decided to put these ideas into action and experiment for myself. 

The results have been astounding. 

In 2 years of prioritizing the 80/20 split of aerobic/anaerobic training and nasal breathing, I have seen: 

• My resting heart rate has gone from 56 bpm (March 2020) to 39 bpm (Feb 2022). This adaptation is called eccentric cardiac hypertrophy - which allows the heart to pump more blood with each beat, meaning the heart doesn’t have to work as hard to deliver oxygen to the blood. 

• My energy is through the roof, and I no longer crash during workouts or the day. I have cut down caffeine consumption from 4 cups of coffee/day to 1-2.

• My performance while running, biking, and lifting have improved. I can work out at a higher level of intensity with more ease. I don’t get “burnt out” as fast!

• My sleep and recovery have improved. I recover faster in between working sets and after workouts for the next day!

• Fat loss and aesthetics are at an all-time high due to proper nutrition and fat oxidation in zone 2.

So, what is going on here? How can lower intensity training 80% of the time give your body the tools to improve at high intensity? Let’s dive in with a few quick points.

1. There are different energy systems within the human body: aerobic vs. anaerobic. Each system uses different muscle fibers. 

   • The aerobic system uses slow-twitch (type I) muscle fibers 

   • The anaerobic system uses fast-twitch (type IIA & IIB) muscle fibers

   • The muscle fibers are differentiated by how forceful and fast the fibers contract – fast-twitch muscle fibers fatigue faster than slow-twitch muscles.

2. The aerobic and anaerobic systems need energy (ATP) to function. How the two systems provide the energy depends on the intensity of your daily activity, exercise, and the demands of the muscle fibers:

   • The aerobic system (endurance system, lower intensity) recruits type I muscle fibers and uses a higher percentage of fatty acids for energy. Fat is slower burning but lasts longer and is more efficient over time. 

   • The anaerobic system (higher intensity, intervals) recruits type II muscle fibers, which use a higher percentage of glucose for energy. Glucose is more immediate energy, but burns out quickly and is less efficient over time.

The more efficient you are at lower intensities while utilizing fat for energy, the more stress your body can tolerate without switching to glucose for energy. 

Why is this important?

When your body switches to glucose for energy, you are essentially on your last source of energy. Glucose burning is limited as your body can only store around 2,000 calories of glucose in the body, versus tens of thousands of calories in fat. 

You want your body to be efficient at burning fat for AS LONG as possible - before it kicks into glucose burning (anaerobic activities), which tire out quickly. 

Aside from a performance aspect, most activity we do throughout life relies on the aerobic system! 

The aerobic system is essential to train because it improves your:

You can also look forward to better weight regulation, mood, and more wellness benefits when your aerobic fitness improves!

4. And lastly - on the breathing front. We absorb 18% more oxygen by breathing in through the nose than through the mouth. Other benefits include:

 I’m in - what is the secret sauce? 

How do we train the aerobic system specifically?

First, we need to know how to calculate the difference between aerobic and anaerobic. You can do this by understanding your heart rate during exercise.

Your heart rate changes depending on the intensity of activity and exercise. Your heart rate can be divided into five different zones in relation to your max heart rate - each heart rate zone uses a distinct blend of muscle fiber and energy.

Your maximal heart rate is 220- (your age)

The Five Heart Rate Zones are:

Zone 1: 50-60% of your max heart rate 

Zone 1 is aerobic and uses a higher type 1 muscle fiber and fat ratio for energy.

Zone 2: 60-70% of your max heart rate 

Z2 is aerobic, uses type 1 muscle fibers, and fat for energy.

Zone 3: 70-80% of your max heart rate

Z3 is both aerobic & anaerobic, uses both type 1 & type 2 muscle fibers, and fat & glucose for energy. This is the zone where lactic acid starts to build up as well.

Zone 4: 80-90% of your max heart rate

Z4 is anaerobic, uses type 2 muscle fibers, and glucose for energy. This is the “speed endurance” zone.

Zone 5: 90-100% of your max heart rate. 

Zone 5 is anaerobic, primarily uses type 2 muscle fibers, glucose, and phosphocreatine for energy. This is an intensity you can only sustain for a few minutes.

For instance, if you are 20 years old, your heart rate max is roughly 220-you age = 200 beats per minute. Your heart rate max is very hard to achieve but it would be when you are doing an all-out sprint for a minute.

Then your zones would be as follows:

Zone 1 = 50-60% of 200 = 100-120 beats per minute. Very light intensity.

Zone 2 = 60-70% of 200 = 120-140 beats per minute. Light intensity.

Zone 3 = 70-80% of 200 = 140-160 beats per minute. Moderate Intensity.

Zone 4 = 80-90% of 200 = 160-180 beats per minute. High Intensity.

Zone 5 = 90-100% of 200= 180-200 beats per minute. All Out Intensity.

So, what are your next steps towards Zone 2 training?

1. You will want to choose a type of cardio to do each week. My favorite aerobic exercises:

• Running

• Jogging

• Hiking

• Swimming

• Rowing

1. Calculate your Zone 2 heart rate. And to do that, you will want some sort of heart rate monitor (Apple watch, Garmin, Whoop strap, or a chest monitor)

Spend 80% of your cardio per week in Zone 2. 

Spend the other 20% training Zones 3- 5 however you decide. Get in sprints, intervals, and speed endurance.

Zone 2 coincides with the heart rate zone, where you use the highest amount of fat for energy before using glucose. This is because Type I fibers use fat, and it is not until Zone 3 that your body starts to recruit Type II fibers, which utilize carbohydrates.

This is why Zone 2 is KING!

1. Dedicate a few 30-60 minute sessions of Zone 2 per week. Studies show that 2-3 hours of aerobic exercise/week is a fantastic place to be, but work your way up to this level. One hour is better than none!

2. You want to breathe in through your nose - simple.

If you do not have a heart rate monitor, Zone 2 is meant to be right on the edge where you can carry out a conversation, but you will have a bit of difficulty if you go any faster. You can talk, but you’re not able to sing a song.

It’s pretty simple when you get the hang of it. I run four times a week with an apple watch. In 3 of those runs, I monitor my heart rate and stay around 135-150 bpm the entire time. On the 4th run, I do intervals and sprints - and push the pace. I have learned that slow is fast when it comes to running or cardiovascular endurance. Hopefully, you’ve learned a few new strategies in this guide to cardio training. Build that base, and you will improve everything related to your health!

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