Having a basic understanding of aerobic vs. anaerobic exercise is a great starting point if you want to get in shape, lose weight, or improve your athletic performance. Both forms of activity can be incorporated into a workout, regardless of whether the best ergometers are used (opens in new tab)going to the gym or playing a team sport.
Aerobic exercise is usually classified as cardio activity that lasts more than two minutes and includes sports such as running and cycling. Anaerobic exercise is generally classified as short, intense bursts of movement (think sprinting and jumping.)
However, some researchers argue that these classifications are useless and reductive. We spoke to Alan Ruddock, lecturer in sport and exercise physiology at Sheffield Hallam University, to find out more.
What is aerobic and anaerobic exercise?
Simply put, aerobic means “with oxygen” and refers to the body producing energy using air. Anaerobic means “without oxygen” and refers to the body producing energy without the use of air.
When you do aerobic exercise, you rely on oxygen as your main source of energy. During more intense bouts of anaerobic exercise, your body needs to get energy quickly, so it relies on stored glucose instead.
However, we actually use both energy systems for most forms of exercise – so you can’t really classify certain activities as purely aerobic or anaerobic.
“The way we assess aerobic exercise is through a face mask of an athlete running on a treadmill or bike,” says Ruddock. “We estimate their oxygen uptake and can use that information to determine the aerobic contribution to a specific task.”
Ruddock explains that during these tests, the team never found an overwhelming dominance of aerobic or anaerobic energy contributions—there was always just a predominance.
Ruddock is an accredited sports and exercise scientist and a member of the British Association for Sport and Exercise Sciences. Currently Laboratory Director for the Center for Sport and Physical Activity Research in Sheffield (UK), he has provided physiological support to Olympians, Paralympians, World Champions, Commonwealth Champions, European and British Champions across a range of sports and co-authored over 25 scientific manuscripts.
To support this, a study published in the Journal of Science and Medicine in Sport (opens in new tab) found that a 100-meter sprint was powered by 21% aerobic energy for men and 25% for women. So even though sprinting is primarily an anaerobic activity, much of the energy during exercise can still come from the aerobic system.
As such, Ruddock says it’s important not to use the terms aerobic and anaerobic exclusively and to understand that all exercise uses both energy systems.
Some sports scientists have even called for the terms aerobic and anaerobic to be replaced because of their misuse.
In an article in Sports Medicine (opens in new tab) sports scientists Karim Chamari and Johnny Padullo suggest that researchers and practitioners use the terms explosive effort, high-intensity effort, and intense endurance effort instead.
What is primarily aerobic or anaerobic exercise?
Whether an exercise is primarily aerobic or anaerobic depends on its intensity and duration. As a general rule, the longer the duration of an exercise, the stronger the aerobic predominance. This is partly because the intensity of an exercise will drop the longer you do it.
There are other ways to separate the two types of exercise. Predominantly aerobic exercise is something at an intensity of 75% maximum heart rate, and it’s something that a person can sustain for a long time. Examples include long-distance running or team sports. Explosive activities such as weight training or sprinting are primarily anaerobic. Meanwhile, high-intensity interval training is in the middle.
If you focus on predominantly anaerobic activities (explosive, intense movements), be sure to include long enough recovery periods between sessions.
“If you repeat a predominantly anaerobic exercise—like a six- to 10-second sprint—by the tenth repetition, there’s a reduction in the amount of anaerobic energy and the aerobic system kicks in. If there’s only a short recovery time, she becomes quite aerobic by the end,” says Ruddock.
This is supported by a study in the Journal of Physiology (opens in new tab) indicating that power output was derived mostly from the aerobic energy system in the tenth repetition of a six-second sprint when the athletes had only 30 seconds of recovery time.
What are the benefits of aerobic and anaerobic exercise?
For overall fitness, both aerobic and anaerobic are important for different reasons.
Aerobic exercise is important for cardiovascular health because it keeps the heart and blood vessels healthy and reduces the risk of heart-related diseases. If you want to lose weight or get fitter, then your body will need more heavy aerobic exercise, but this should be backed up with mostly anaerobic strength training to prevent injury.
In comparison, anaerobic exercise is important for strength, coordination and maintaining muscle mass. The American Heart Association recommends strength training at least twice a week to protect the body from injury and maintain mobility in old age.
Anaerobic activity will also help with metabolic health, meaning the body is able to respond to food in a beneficial way, reducing the risk of obesity, type 2 diabetes, heart disease and stroke.
This article is not intended to offer medical advice and readers should consult their physician or health professional before adopting any diet or exercise regimen.