Nearly everybody will have heard the terms “aerobic” and “anaerobic” used in the context of running training, but not everybody understands the difference.

Aerobic Training

Aerobic training essentially means that you are running/training at a low heart rate. It can also be thought of as running at an intensity which would allow you to carry out a conversation. During aerobic running you burn fat as your main source of energy. Aerobic training doesn’t put as much stress on your body as anaerobic training and you don’t need as much recovery time between training sessions, therefore you are less likely to suffer from injury or illness if the bulk of your training is aerobic.

Your aerobic system provides a solid foundation for good health. It is the system that builds up the muscles which help you to move efficiently throughout the day and support your overall posture. Training your aerobic system increases mitochondria in your muscle cells. These mitochondria generate energy (ATP) and improve your blood circulation which improves your bodies ability to utilise oxygen.

Aerobic conditioning is a necessary foundation of virtually all training. The longer an event, the more your body will rely on the aerobic system. A strong aerobic base will even benefit your recovery in-between sets of strength training as well as anaerobic interval training too.

Anaerobic Training

Anaerobic training is training at a higher heart rate, or an intensity at which you might only be able to speak two or three words before needing to draw another breath. It essentially means training without oxygen.

Anaerobic training puts a lot more stress on your body. It puts more stress on your muscles and joints because you are running at a faster pace. Anaerobic training sessions, like hill repeats or 1km intervals, take longer for your body to recover from, therefore, your training program needs to be structured to allow enough recovery time after these sessions to minimise the risk of you getting injured or sick.

As an endurance athlete, you need to improve your aerobic efficiency

If you constantly use your anaerobic system more than your aerobic system (by training too fast), it puts a major stress on your entire body – your nervous system, cardiovascular system, hormonal system, immune system, and digestive system – pretty much all of it.

By following a properly structured training program, which has a base-building block of 8-12 weeks of predominantly aerobic training, you can improve your aerobic capacity, which will improve your ability to run faster over longer distances.

For example, if you are out for a 90 minute run, and your aerobic system is very poor, then you might be running at say 70% anaerobic and 30% aerobic. But if you develop your aerobic system correctly, then at that same pace you could flip the energy utilisation to 70% aerobic, 30% anaerobic. This will make you a much more efficient athlete. This can be assessed using a heart rate monitor when you run. Over time, as you develop your aerobic efficiency, you will see that your heart rate is lower at a given pace/exertion level than what it was in the weeks or months previously.

Do you want to learn what your training heart rate zones should be?

There are all sorts of formulas you can use to calculate your heart rate zones, but unfortunately, not many of them end up being very accurate. They don’t allow for variations in heart rate size, which can have a major influence on your heart rate range.

If you want to know your exact training zones, you can book an appointment with a sports scientist who specialises in lab testing runners. They will measure your lactate threshold to calculate your heart rate training zones. They can also measure your “fuel efficiency” – to find out how much fat and how much sugar you burn when you run.