From Wikipedia, the free encyclopedia
Aerobic exercise (also known as cardio) is physical exercise of low to high intensity that depends primarily on the aerobic energy-generating process. “Aerobic” means “relating to, involving, or requiring free oxygen”, and refers to the use of oxygen to adequately meet energy demands during exercise via aerobic metabolism. Generally, light-to-moderate intensity activities that are sufficiently supported by aerobic metabolism can be performed for extended periods of time. What is generally called aerobic exercise might be better termed “solely aerobic”, because it is designed to be low-intensity enough so that all carbohydrates are aerobically turned into energy.
When practiced in this way, examples of cardiovascular or aerobic exercise are medium to long distance running or jogging, swimming, cycling, and walking.
British physiologist, Archibald Hill 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. Notable contributions were made by Henry Taylor at the University of Minnesota, Scandinavian scientists Per-Olof Åstrand and Bengt Saltin in the 1950s and 60s, the Harvard Fatigue Laboratory, German universities, and the Copenhagen Muscle Research Centre among others.
After World War II, non-organized, individualistic, health-oriented physical and recreational activities, such as jogging, began to become popular. The Royal Canadian Air Force Exercise Plans, developed by Dr. Bill Orban and published in 1961, helped to launch modern fitness culture. There was a running boom in the 1970s, inspired by the Olympics.
Physical therapist, Col. Pauline Potts and Dr. Kenneth 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. Cooper published his ideas in a 1968 book titled, “Aerobics“. In 1970, he created his own institute (the Cooper Institute) for non-profit research and education devoted to preventive medicine and 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”. Aerobics developed as an exercise form in the 1970s and became popular worldwide in the 1980s after the release of Jane Fonda’s exercise videos in 1982.
What qualifies as aerobic exercise
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 golf or two person team tennis, with brief bursts of activity punctuated by more frequent breaks, may not be predominantly 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 versus anaerobic exercise
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 exercises because the less efficient anaerobic metabolism must supplement the aerobic system due to energy demands that exceed the aerobic system’s capacity. Common kettlebell exercises combine aerobic and anaerobic aspects.
Cooper himself defines aerobic exercise as the ability to use the maximum amount of oxygen during exhaustive work. Cooper describes some of the major health benefits of aerobic exercise, such as gaining more efficient lungs by maximizing breathing capacity, thereby increasing ability to ventilate more air in a shorter period of time. As breathing capacity increases, one is able to extract oxygen more quickly into the blood stream, increasing elimination of carbon dioxide. With aerobic exercise the heart becomes more efficient at functioning, and blood volume, hemoglobin and red blood cells increase, enhancing the ability of the body to transport oxygen from the lungs into the blood and muscles. Metabolism will change and enable consumption of more calories without putting on weight. Aerobic exercise can delay osteoporosis as there is an increase in muscle mass, a loss of fat and an increase in bone density. With these variables increasing, there is a decrease in likelihood of diabetes as muscles use sugars better than fat. One of the major benefits of aerobic exercise is that body weight may decrease slowly; it will only decrease at a rapid pace if there is a calorie restriction, therefore reducing obesity rates.
Among the recognized health benefits of doing regular aerobic exercise are:
- Strengthening the muscles involved in respiration, to facilitate the flow of air in and out of the lungs
- Strengthening and enlarging the heart muscle, to improve its pumping efficiency and reduce the resting heart rate, known as aerobic conditioning
- Improving circulation efficiency and reducing blood pressure
- Increasing the total number of red blood cells in the body, facilitating transport of oxygen
- Improving mental health, including reducing stress and lowering the incidence of depression, as well as increased cognitive capacity.
- Reducing the risk for diabetes (One meta-analysis has shown, from multiple conducted studies, that aerobic exercise does help lower Hb A1C levels for type 2 diabetics.)
- Reducing the risk of death due to cardiovascular problems
High-impact aerobic activities (such as jogging or using a skipping rope) can:
Body performance benefits
In addition to the health benefits of aerobic exercise, there are numerous performance benefits:
- Increasing storage of energy molecules such as fats and carbohydrates within the muscles, allowing for increased endurance
- Neovascularization of the muscle sarcomeres to increase blood flow through the muscles
- Increasing speed at which aerobic metabolism is activated within muscles, allowing a greater portion of energy for intense exercise to be generated aerobically
- Improving the ability of muscles to use fats during exercise, preserving intramuscular glycogen
- Enhancing the speed at which muscles recover from high intensity exercise
- Improvement in brain structural connections
- Increase in gray matter density
- New neuron growth
- Improvement in cognitive function (cognitive control and various forms of memory)
- Improvement or maintenance of mental health
Some drawbacks of aerobic exercise include:
- Overuse injuries because of repetitive, high-impact exercise such as distance running
- Is not an effective approach to building muscle
- Not an effective form of fat loss, unless used consistently
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.
Activities similar to aerobic exercise
- Higher intensity exercise, such as High-intensity interval training (HIIT), increases the resting metabolic rate (RMR) in the 24 hours following high intensity exercise, ultimately burning more calories than lower intensity exercise; low intensity exercise burns more calories during the exercise, due to the increased duration, but fewer afterwards.
Success in aerobic exercise businesses
Aerobic exercise has long been a popular approach to achieving weight loss and physical fitness, often taking a commercial form.
- In the 1970s, Judi Sheppard Missett helped create the market for commercial aerobics with her Jazzercise program
- In the 1980s, Richard Simmons hosted an aerobic exercise show on television, and also released a series of exercise videos
- In the 1990s, Billy Blanks’s Tae Bo helped popularize cardio-boxing workouts that incorporated martial arts movements
Types of aerobic exercise
- 5BX, for men
- XBX, for women
- Anaerobic exercise
- High-intensity interval training
- Exercise physiology
- Cellular respiration