Skip to content

Why we exercise II: Anaerobic fitness

We wrote a while ago about aerobic or cardiovascular fitness and its importance. in this article we take a look at anaerobic fitness and its importance when it comes to sport and physical activity.

Anaerobic exercise is a higher intensity, higher power version of exercise and it is very effective as a means of increasing your fitness levels.

There is every likelihood that you already incorporate this type of fitness into your training regime, but it is worth knowing a bit more about it. This will help you develop a training plan that is more effective and hits your goals and targets.

Oxygen debt

Anaerobic training is the exercise that leaves you seriously breathless. It is the exercise that you can only do to a high intensity for a very short period of time. Sprinting, jumping, flat-out cycling, weightlifting – these are all forms of anaerobic activity. 

The reason anaerobic exercise can only be carried out for short periods of time is that it demands more energy than your body can provide. This is where it differs form aerobic energy. When you are doing a lower intensity exercise, the body’s oxygen supply is sufficient to sustain the level of activity without needing energy from another source.

Put simply: aerobic means ‘with oxygen’, anaerobic means ‘without oxygen.

Calling on energy supply

When you are working harder than your body’s oxygen supply can cope with, then your body seeks energy from another source – the energy stored in muscles as glucose.

When you are working at a high intensity, the body responds through the process of glycolysis. Energy is produced quickly and feeds the body the energy it needs but only for short bursts. The by-product is lactic acid, which builds up until your muscles can’t cope.

Anaerobic fitness training helps your muscles tolerate and dispel lactic acid more quickly, meaning you can train and perform at a  higher intensity for longer. 

Benefits of anaerobic exercise

There are a lot of benefits to developing high anaerobic fitness levels:

Bone strength and density improves, lessening your chance of injury or developing osteoporosis. It also means you are less likely to develop heart disease and diabetes. 

Good levels of anaerobic fitness help with weight management. This type of fitness helps boost your metabolism as it builds and maintains lean muscle. In turn, this means you burn more calories during a work out as lean muscle burns more calories. 

Short, sharp and intense training can also improve your power – whether that is lifting weights, sprinting, jumping or throwing. 

By building muscle strength and mass your joints will be better protected from injury.

You will build your ability to store glycogen, which in turn means you will have higher energy levels. 

Here are three forms of exercise that will improve anaerobic fitness.


This could be a set of sprints on a track, but equally, you can build sprints into other exercise sessions. If you are out for a run, build in sprints every so often. Over a five kilometre run, aim to do a total of 15 sprints of varying length – maybe between lamp posts or to a tree. Aim for sprints between 10 to 30 seconds.

If you are cycling or rowing, add in some bursts of high intensity speed play. again, no more than 30 seconds working at 100 per cent of your ability. 

High Intensity Interval Training (HIIT).

This can be in the form of circuits or weight training. The idea is to work at 90 per cent of your maximum effort or higher for 10-15 seconds, followed by a 30-60 second recovery (this can be an active recovery such as jogging). Sets of 6-8 repetitions for 10-12 exercise stations will give a great workout. (See also Tabata training).


This refers to exercises that use raw power, such as jumping or hopping. While the exercises are primarily used to gain power in the legs and lower body, they are also anaerobic based as they rely on a short burst of energy for maximum result. Examples of plyometrics are: lunge jumps, squat jumps, burpees, box jumps and low hurdles. These can be built into a circuit, with short rests between periods of intense work. 

For further information on the benefits of anaerobic training, speak to one of our personal trainers at the Outlooks Gym or Free Weights Gym and to read more info check out this article.