Aerobic exercise (also known as endurance activities, cardio or cardio-respiratory exercise) is physical exercise of low to high intensity that depends primarily on the aerobic energy-generating process. "Aerobic" is defined as "relating to, involving, or requiring oxygen", and refers to the use of oxygen to meet energy demands during exercise via aerobic metabolism adequately. Aerobic exercise is performed by repeating sequences of light-to-moderate intensity activities for extended periods of time. Aerobic exercise may be better referred to as "solely aerobic", as it is designed to be low-intensity enough that all carbohydrates are aerobically turned into energy via mitochondrial ATP production. Mitochondria are organelles that rely on oxygen for the metabolism of carbs, proteins, and fats.
Examples of cardiovascular or aerobic exercise are medium- to long-distance running or jogging, swimming, cycling, stair climbing and walking.
Archibald Hill, a British physiologist, introduced the concepts of maximal oxygen uptake and oxygen debt in 1922. German physician Otto Meyerhof and Hill shared the 1922 Nobel Prize in Physiology or Medicine for their independent work related to muscle energy metabolism. Building on this work, scientists began measuring oxygen consumption during exercise. Henry Taylor at the University of Minnesota and Scandinavian scientists Per-Olof Åstrand and Bengt Saltin made notable contributions in the 1950s and 60s. Contributions were also made by the Harvard Fatigue Laboratory, Copenhagen Muscle Research Centre as well as various German universities.
After World War II, health-oriented recreational activities such as jogging became popular. The Royal Canadian Air Force Exercise Plans, developed by Dr. Bill Orban and published in 1961, helped to launch modern fitness culture.
Physical therapists Col. Pauline Potts and Dr. Kenneth H. Cooper, both of the United States Air Force, advocated the concept of aerobic exercise. In the 1960s, Cooper started research into preventive medicine. He conducted the first extensive research on aerobic exercise on over 5,000 U.S. Air Force personnel after becoming intrigued by the belief that exercise can preserve one's health. In 1966 he coined the term "aerobics". Two years later, in 1968, he published a book of the same name. In 1970, he created the Cooper Institute for non-profit research and education devoted to preventive medicine. He published a mass-market version of his book The New Aerobics in 1979. Cooper encouraged millions into becoming active and is now known as the "father of aerobics". Cooper's book inspired Jacki Sorensen to create aerobic dancing exercise routines, which grew in popularity in the 1970s in the U.S., and at the same time, Judi Missett developed and expanded Jazzercise.
In the 1970s, there was a running boom. It was inspired by the Olympics, the New-York marathon and the advent of cushioned shoes.
Aerobics at home became popular worldwide after the release of Jane Fonda's Workout exercise video in 1982. Step aerobics was popular in the 1990s, driven by a step product and program from Reebok shoes.
Main article: Bioenergetic systems
Aerobic exercise comprises innumerable forms. In general, it is performed at a moderate level of intensity over a relatively long period of time. For example, running a long distance at a moderate pace is an aerobic exercise, but sprinting is not. Playing singles tennis, with near-continuous motion, is generally considered aerobic activity, while activities with brief bursts of energetic movement within longer periods of casual movement may not be aerobic. Some sports are thus inherently "aerobic", while other aerobic exercises, such as fartlek training or aerobic dance classes, are designed specifically to improve aerobic capacity and fitness. It is most common for aerobic exercises to involve the leg muscles, primarily or exclusively. There are some exceptions. For example, rowing to distances of 2,000 meters or more is an aerobic sport that exercises several major muscle groups, including those of the legs, abdominals, chest, and arms.
Aerobic exercise and fitness can be contrasted with anaerobic exercise, of which strength training and short-distance running are the most salient examples. The two types of exercise differ by the duration and intensity of muscular contractions involved, as well as by how energy is generated within the muscle.
New research on the endocrine functions of contracting muscles has shown that both aerobic and anaerobic exercise promote the secretion of myokines, with attendant benefits including growth of new tissue, tissue repair, and various anti-inflammatory functions, which in turn reduce the risk of developing various inflammatory diseases. Myokine secretion in turn is dependent on the amount of muscle contracted, and the duration and intensity of contraction. As such, both types of exercise produce endocrine benefits.
In almost all conditions, anaerobic exercise is accompanied by aerobic (in the presence of oxygen) exercises because the less efficient anaerobic metabolism must supplement the aerobic system due to energy demands that exceed the aerobic system's capacity. During anaerobic exercise, the body must generate energy through other processes than aerobic metabolism, including glycolysis paired with lactic acid fermentation, and the phosphocreatine system to generate energy in the form of ATP. Common kettlebell exercises combine aerobic and anaerobic aspects. Allowing 24 hours of recovery between aerobic and strength exercise leads to greater fitness.
Depending on the intensity of exercise, the body preferentially utilizes certain fuel forms to meet energy demands. The two main fuel sources for aerobic exercise in the body include fat (in the form of adipose tissue) and glycogen. At lower intensity aerobic exercise, the body preferentially uses fat as its main fuel source for cellular respiration, however as intensity increases the body preferentially uses glycogen stored in the muscles and liver or other carbohydrates, as it is a quicker source of energy. Aerobic exercise is not a very efficient way to burn fat in comparison to other forms of exercise, as in order to preferentially burn fat one should exercise at lower intensities, which decreases the overall amount of calories burned per unit of time.
Among the recognized health benefits of doing regular aerobic exercise are:
High-impact aerobic activities (such as jogging or using a skipping rope) can:
Some drawbacks of aerobic exercise include:
Both the health benefits and the performance benefits, or "training effect", require that the duration and the frequency of exercise both exceed a certain minimum. Most authorities suggest at least twenty minutes performed at least three times per week.
The National Institute on Aging's Go4Life initiative has a YouTube channel of suggested exercises for older adults.
The NIA recommends a number of measures for safety during aerobic exercise:
Aerobic exercise has long been a popular approach to achieving weight loss and physical fitness, often taking a commercial form.
|Indoor||Outdoor||Indoor or outdoor|
|Stationary bicycle||Running||Skipping rope or jump rope|
|Treadmill||Cross-country skiing||Circuit training|
|Aerobic dancing||Cross-country running||Jumping jacks|
|Jazzercise||Nordic walking||Water aerobics|
|Step aerobics||Inline skating||Jogging|
In fact, the popularity of the Royal Canadian Air Force's calisthenics program in the late 1950s helped launch the modern fitness movement.
The program became famous worldwide.