Aerobic v Anaerobic exercise

When looking at Anaerobic v aerobic physical activity there are 2 options. Anaerobic lacks oxygen and aerobic requires oxygen. Aerobic exercise increases your endurance and cardiac health while anaerobic exercise will not only help you burn fat but also help you gain lean muscle mass. During physical activity, your body has to convert high-energy phosphates called ATP to low-energy phosphates called AMP, ADP and P.

Our muscles don’t store many high-energy phosphates, so the body uses three different metabolic pathways. This depends on how quickly it needs energy.

All three energy systems work together to keep you moving. Although different types of exercise would rely more heavily on certain systems. For example, lifting a heavy weight requires more energy quickly than going for a slow jog, so each uses different systems.

Understanding what is happening in your body as you transit between systems is very cool. This gives you the inside knowledge on why you’re feeling the way you feel. You will understand why you feel puffed at certain times. On the other hand why you want to collapse on the floor after giving it your all.




Anaerobic a-lactic system

Otherwise known as the creatine phosphate system. This system kicks in when the body needs a lot of power quickly. In cases such as doing maximum weight squats, long jump or a 100m sprint.

Given you’re asking a lot of strength or speed from your body, there is a high demand for ATP (adenosine triphosphate). So it needs a fast, efficient system to get the energy cranking.

This system taps into creatine phosphate from the skeletal muscles and quickly synthesises it into ATP for quick bursts of intense energy.  But given there’s only a small amount of phosphorous in the skeletal muscles, fatigue occurs quickly as well. And you’ll only get about 10 seconds of absolutely smashing yourself before fatigue kicks in.


Anaerobic v Aerobic exercise: The anaerobic lactic system

Also known as glycolysis. This is the energy system used for high-intensity exercise for anywhere between 30 seconds and about two minutes.

It’s often used at the start of exercise because the body can’t deliver oxygen to the muscles fast enough (via the aerobic system). So it uses the anaerobic lactic system to get you going.

This system uses carbohydrates from either blood sugar or glycogen stored in the muscles and breaks it down to produce ATP.

For every molecule of glucose, you get two molecules of ATP and while the energy will last longer than the anaerobic a-lactic system. It will still only give you a couple of minutes worth of activity before you start to become fatigued.

But because you haven’t been using oxygen, you’ll find yourself really out of breath and gasping for air.


Aerobic v Anaerobic exercise: The aerobic system

This system is dependent on oxygen and while it’s the slowest method for producing ATP, it produces the biggest volume and is the system our body relies on for everyday processes.

In this system, the mitochondria (cell powerhouses) use blood glucose, glycogen and fat to create ATP.

It’s the system that keeps us going through longer endurance events because it produces 18 times more ATP than the anaerobic lactic system.


All systems are valuable and a necessary step in increasing your overall fitness. If you find yourself better at longer workouts where pacing is necessary, maybe try some short, intense training eg max cal airbike for 60 sec or 100m sprints on the rower. Start small to get used to this feeling then as the body gets used to pushing through and adapting then you can build on this. Your max deadlifts and squats will improve too as your increase in power does.J


Looking to gain more momentum with your movement? Watch this video with one of The Chiefs for more. Have you thought about how your food can impact your performance and recovery? Why not have a free consultation to see how we can help you get started.


Nicole McDermott

I am passionate about working with people on a holistic level to balance hormones, improve mood, manage weight all whilst educating people on the benefits of a balanced whole foods diet. Follow more great advice from Nic here.