Aerobic vs Anaerobic Training
Written by Fritz Nugent

What is aerobic vs anaerobic conditioning? What benefits do you achieve from the two different types of conditioning? If you’ve ever wondered about these two questions, you are not alone! Here’s a little breakdown to help you out.

Aerobic vs Anaerobic

If you put an HR monitor on and performed your training, this would tell us with accuracy what zone you’re training in. The aerobic training zones are zones 0-2.

Aerobic work is traditionally one task (bike, run, sled pull, weight vest walk, row, ski, etc.) performed with a HR of 180 minus your age. It’s very difficult for people to maintain an aerobic-dominant energy output in CrossFit due to the variety, mixed modal tasks, the drive to compete with classmates that many people experience in a group class, and the increasingly outdated CrossFit stigma that people have to go as hard as possible each day to reap all the benefits. As for benefits, aerobic training increases your capacity to perform submaximal work and improves your body’s ability to sustainably fuel movement with proteins, carbohydrates, and fats as the main fuel sources.

Anaerobic training increases your body’s capacity to perform work using creatine-phosphate (the readily available and duration-limited ATP-replenishing compound), and glycogen (long chains of glucose broken down and utilized to create ATP), and fatty acids at an unsustainable rate. By unsustainable, I mean that you can not maintain this pace for a long time. The build-up of bi-products during anaerobic training reduces your output or even demands that you cease your interval bout altogether, and we experience this as a burning sensation in the muscles and/or high cardiorespiratory strain. In order to be a good CrossFitter, training this way is a must. However, it is arguably unnecessary to train this way to simply live healthily.

Is a dose of anaerobic intensity good for you? I would argue yes. There is plenty of research on the benefits of lactate, which is an important bi-product of anaerobic training. You can train anaerobically using strength training. Is training daily for long durations solely in anaerobic zones an optimal approach? I would argue no to that.

Which is better for you?

Aerobic training + strength training = all you need to stay healthy. Personally, I think people become addicted to the anaerobic nature of CrossFit because they can “feel” how hard it is. Aerobic training doesn’t feel that way. You can carry out a full conversation with someone else while training aerobically. People equate this to a workout that is less effective than a high-intensity session. The reality is that people are missing out on an opportunity to gain improved system function. When the body recovers from anaerobic intervals, the aerobic system is the PRIMARY RECOVERY SYSTEM!

Before moving on, let’s take a closer look at strength training. By nature, strength training is anaerobic, meaning that during a working set, fatigue and metabolic bi-products build to a point that causes us to stop. Why can you only squat 80% for ~10 reps? Because your body is literally physically incapable of producing more work than that.

As it relates to your health, aerobic training can acutely reduce stress on the central nervous and immune systems and can stimulate a parasympathetic nervous system response. Aerobic training places less physiological stress on the body and immune system compared to HIIT-style training or heavy weightlifting cycles. Because it is less demanding on the CNS and creates fewer bi-products, it is less inflammatory to the body, which reduces immune system stress. If you’re stressed out on life (sympathetic response), Zone 2 aerobic work also facilitates a parasympathetic response in the body (think “flow state”).

How to Add More Aerobic Training to Your Week

That would look like longer runs, bike, row, ski, sled, carries, and mixed modal work with lighter weight and longer rest breaks to keep HR within the aerobic zone. Many of our “Motor” sessions have an intended aerobic stimulus and can be approached with that stimulus in mind. So if you want to give your nervous system a break, choose exercise and movement that will be rejuvenating rather than demanding on your nervous and immune system. Feeling refreshed instead of fatigued or beat down after a training session is a good sign that you’re on the right track here. Zone 2 aerobic work can keep you healthy and fit for the long haul.


Also Check Out…
Getting to Know the 5 Heart Rate Training Zones
Aerobic Training Zone 2
Is Training Leaving You Sore or Beat Up?