Aerobic exercise

Cardio and muscle endurance

Aerobic exercise (also known as cardio) is physical exercise of low to high intensity that depends primarily on the aerobic energy-generating process.[1] Aerobic literally means "relating to, involving, or requiring free oxygen",[2] and refers to the use of oxygen to adequately meet energy demands during exercise via aerobic metabolism.[3] Generally, light-to-moderate intensity activities that are sufficiently supported by aerobic metabolism can be performed for extended periods of time.[1]

When practiced in this way, examples of cardiovascular/aerobic exercise are medium to long distance running/jogging, swimming, cycling, and walking.

History

British physiologist Archibald Hill introduced the concepts of maximal oxygen uptake and oxygen debt in 1922.[4][5] Hill and German physician Otto Meyerhof shared the 1922 Nobel Prize in Physiology or Medicine for their independent work related to muscle energy metabolism.[6] 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.[7][8]

After World War II, non-organized, individualistic, health-oriented physical and recreational activities such as jogging began to become popular.[9] The Royal Canadian Air Force Exercise Plans developed by Bill Orban and published in 1961 helped to launch modern fitness culture.[10][11] There was a running boom in the 1970s inspired by the Olympics.[12]

Dr. Kenneth Cooper and Col. Pauline Potts, a physical therapist, 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[13][14] after becoming intrigued by the belief that exercise can preserve one's health. Cooper published his ideas in a 1968 book "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".[15][16] 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.[17][18]

Aerobic versus anaerobic exercise

Fox and Haskell formula showing the split between aerobic (light orange) and anaerobic (dark orange) exercise and heart rate

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.[19]

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.[20]

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. What is generally called aerobic exercise might be better termed "solely aerobic", because it is designed to be low-intensity enough not to generate lactate via pyruvate fermentation, so that all carbohydrate is aerobically turned into energy.

Initially during increased exertion, muscle glycogen is broken down to produce glucose, which undergoes glycolysis producing pyruvate which then reacts with oxygen (Krebs cycle, Chemiosmosis) to produce carbon dioxide and water and releases energy. If there is a shortage of oxygen (anaerobic exercise, explosive movements), carbohydrate is consumed more rapidly because the pyruvate ferments into lactate. If the intensity of the exercise exceeds the rate with which the cardiovascular system can supply muscles with oxygen, it results in buildup of lactate and quickly makes it impossible to continue the exercise. Unpleasant effects of lactate buildup initially include the burning sensation in the muscles, and may eventually include nausea and even vomiting if the exercise is continued without allowing lactate to clear from the bloodstream.

As glycogen levels in the muscle begin to fall, glucose is released into the bloodstream by the liver, and fat metabolism is increased so that it can fuel the aerobic pathways. Aerobic exercise may be fueled by glycogen reserves, fat reserves, or a combination of both, depending on the intensity. Prolonged moderate-level aerobic exercise at 65% VO2 max (the heart rate of 150 bpm for a 30-year-old human) results in the maximum contribution of fat to the total energy expenditure. At this level, fat may contribute 40% to 60% of total, depending on the duration of the exercise. Vigorous exercise above 75% VO2max (160 bpm) primarily burns glycogen.[21][22]

Major muscles in a rested, untrained human typically contain enough energy for about 2 hours of vigorous exercise. Exhaustion of glycogen is a major cause of what marathon runners call "hitting the wall". Training, lower intensity levels, and carbohydrate loading may allow postponement of the onset of exhaustion beyond 4 hours.[22]

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 m or more is an aerobic sport that exercises several major muscle groups, including those of the legs, abdominals, chest, and arms. Common kettlebell exercises combine aerobic and anaerobic aspects.

Benefits

Among the recognized benefits of doing regular aerobic exercise are:[23]

  • 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
  • Improved mental health, including reducing stress and lowering the incidence of depression, as well as increased cognitive capacity.[24]
  • Reducing the risk for diabetes. One meta-analysis has shown, from multiple conducted studies, that aerobic exercise does help lower Hb A1Clevels for type 2 diabetics.[25]

As a result, aerobic exercise can reduce the risk of death due to cardiovascular problems. In addition, high-impact aerobic activities (such as jogging or using a skipping rope) can stimulate bone growth, as well as reduce the risk of osteoporosis for both men and women.

In addition to the health benefits of aerobic exercise, there are numerous performance benefits:

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
  • Only effective for fat loss when used consistently

Both the health benefits and the performance benefits, or "training effect", require a minimum duration and frequency of exercise. Most authorities suggest at least twenty minutes performed at least three times per week.[26]

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 maximising 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.[27]

Aerobic workout

Aerobic capacity

Aerobic capacity describes the functional capacity of the cardiorespiratory system, (the heart, lungs and blood vessels). Aerobic capacity refers to the maximum amount of oxygen consumed by the body during intense exercises, in a given time frame.[28] It is a function both of cardiorespiratory performance and the maximum ability to remove and use oxygen from circulating blood. To measure maximal aerobic capacity, an exercise physiologist or physician will perform a VO2 max test, in which a subject will undergo progressively more strenuous exercise on a treadmill, from an easy walk through to exhaustion. The individual is typically connected to a respirometer to measure oxygen consumption, and the speed is increased incrementally over a fixed duration of time. The higher the measured cardiorespiratory endurance level, the more oxygen has been transported to and used by exercising muscles, and the higher the level of intensity at which the individual can exercise. More simply put, the higher the aerobic capacity, the higher the level of aerobic fitness. The Cooper and multi-stage fitness tests can also be used to assess functional aerobic capacity for particular jobs or activities.

The degree to which aerobic capacity can be improved by exercise varies vary widely in the human population: while the average response to training is an approximately 17% increase in VO2max, in any population there are "high responders" who may as much as double their capacity, and "low responders" who will see little or no benefit from training.[29] Studies indicate that approximately 10% of otherwise healthy individuals cannot improve their aerobic capacity with exercise at all.[30] The degree of an individual's responsiveness is highly heritable, suggesting that this trait is genetically determined.[29]

Obesity Table

Aerobic exercise and obesity

Obesity in Australia is becoming a huge issue, with one in four Australians being overweight. Obesity can be deadly as it increases the risk of coronary heart disease, type 2 diabetes and stroke. In Australia it is proven that nearly 40% of males and 60% of females do not do enough physical activity a day. Introducing aerobic exercise to a daily routine would benefit the body and reduce the risk of cardiovascular disease. The Australian Heart Foundation guidelines outline that exercise to reduce fat should involve continuous moderate aerobic exercise. Continuous moderate exercise is easily accessible and should be performed for at least 30 minutes five times a week. This will reduce obesity by 19% versus no activity at all.[31]

Alternatives

Higher intensity exercise, such as High-intensity interval training (HIIT), increases the resting metabolic rate (RMR) in the 24 hours following high intensity exercise,[32] 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.

Commercial success

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

Varieties

Indoor

Outdoor

Indoor or outdoor

See also

Footnotes

  1. 1 2 Sharon A. Plowman; Denise L. Smith (1 June 2007). Exercise Physiology for Health, Fitness, and Performance. Lippincott Williams & Wilkins. p. 61. ISBN 978-0-7817-8406-1. Retrieved 13 October 2011.
  2. ↑ Kenneth H. Cooper (1997). Can stress heal?. Thomas Nelson Inc. p. 40. ISBN 978-0-7852-8315-7. Retrieved 19 October 2011.
  3. ↑ William D. McArdle; Frank I. Katch; Victor L. Katch (2006). Essentials of exercise physiology. Lippincott Williams & Wilkins. p. 204. ISBN 978-0-7817-4991-6. Retrieved 13 October 2011.
  4. ↑ Hale, Tudor (2008-02-15). "History of developments in sport and exercise physiology: A. V. Hill, maximal oxygen uptake, and oxygen debt". Journal of Sports Sciences. 26 (4): 365–400. doi:10.1080/02640410701701016. ISSN 0264-0414. PMID 18228167.
  5. ↑ Bassett, D. R.; Howley, E. T. (1997). "Maximal oxygen uptake: "classical" versus "contemporary" viewpoints". Medicine and Science in Sports and Exercise. 29 (5): 591–603. ISSN 0195-9131. PMID 9140894.
  6. ↑ "The Nobel Prize in Physiology or Medicine 1922". NobelPrize.org. Retrieved 2018-10-11.
  7. ↑ Seiler, Stephen (2011). "A Brief History of Endurance Testing in Athletes" (PDF). SportScience. 15 (5).
  8. ↑ "History of Exercise Physiology". Human Kinetics Europe. Retrieved 2018-10-11.
  9. ↑ Fit Bodies. Fitness Culture and Gym Sassatelli, Roberta. 2006.
  10. ↑ KRUCOFF, CAROL (1998-06-22). "Going Back to the Basics With Calisthenics". Los Angeles Times. ISSN 0458-3035. Retrieved 2018-10-08.
  11. ↑ "Five basic exercises for fitness in 1961". CBC Archives. Retrieved 2018-10-08.
  12. ↑ Stracher, Cameron. "Running on Empty: An American Sports Tradition Fades". Retrieved 2018-10-11.
  13. ↑ Cooper, Kenneth H. (1983) [1968]. Aerobics (revised, reissue ed.). Bantam Books. ISBN 978-0553274479.
  14. ↑ Netburn, Deborah (March 30, 2009), "Dr. Kenneth Cooper got a nation moving through aerobics", Los Angeles Times
  15. ↑ ""Father of Aerobics" Kenneth Cooper, MD, MPH to receive Healthy Cup Award from Harvard School of Public Health". News. 2008-04-16. Retrieved 2018-10-08.
  16. ↑ "Dr. Kenneth Cooper and How He Became Known as the Father of Aerobics". Club Industry. 2008-09-01. Retrieved 2018-10-08.
  17. ↑ "(PDF) The Fitness Revolution. Historical Transformations in a Global Gym and Fitness Culture". ResearchGate. Retrieved 2018-10-07.
  18. ↑ Stern, Marc (2008). "The Fitness Movement and the Fitness Center Industry, 1960-2000" (PDF). Business and Economic History On-line. Retrieved 2018-10-07.
  19. ↑ Wayne, Jake (14 June 2011). "Aerobic Vs. Anaerobic Fitness". LIVESTRONG.COM. Retrieved 21 April 2013.
  20. ↑ Muscle as a secretory organ. Pedersen BK. American Physiological Society. Compr Physiol 3:1337-1362, 2013. http://www.inflammation-metabolism.dk/index.php?pageid=21&pmid=23897689
  21. ↑ "Fat vs. carbohydrate metabolism during aerobic exercise".
  22. 1 2 Matthew J Watt; et al. (June 2002). "Intramuscular triacylglycerol, glycogen and acetyl group metabolism during 4 h of moderate exercise in man". J Physiol. 541 (Pt 3): 969–78. doi:10.1113/jphysiol.2002.018820. PMC 2290362. PMID 12068055.
  23. ↑ "Aerobic exercise: the health benefits". myDr. 11 January 2010. Retrieved 17 May 2016.
  24. ↑ "Cardiovascular fitness is linked to intelligence".
  25. ↑ Snowling, N. J., & Hopkins, W. G. (2006). Effects of Different Modes of Exercise Training on Glucose Control and Risk Factors for Complications in Type 2 Diabetic Patients A meta-analysis. Diabetes Care, 29(11), 518–2527. http://doi.org/10.2337/dc06-1317
  26. ↑ 'aerobic exercise', Food and Fitness: A Dictionary of Diet and Exercise, Michael Kent, Oxford University Press, 1997.
  27. ↑ Cooper, Kenneth H. (2010). "The Benefits Of Exercise In Promoting Long And Healthy Lives – My Observations". Methodist DeBakey Cardiovascular Journal. 6 (4): 10–12. doi:10.14797/mdcj-6-4-10.
  28. ↑ Hebestreit, Helge; Bar-Or, Oded (2008). The Young Athlete. Blackwell Publishing Ltd. p. 443. ISBN 978-1-4051-5647-9. Retrieved 29 July 2014.
  29. 1 2 Bouchard, Claude; Ping An; Treva Rice; James S. Skinner; Jack H. Wilmore; Jacques Gagnon; Louis Perusse; Arthus S. Leon; D. C. Rao (1 September 1999). "Familial aggregation of VO(2max) response to exercise training: results from the HERITAGE Family Study". Journal of Applied Physiology. 87 (3): 1003–1008. doi:10.1152/jappl.1999.87.3.1003. PMID 10484570. Retrieved 2007-07-17.
  30. ↑ Kolata, Gina (February 12, 2002). "Why Some People Won't Be Fit Despite Exercise". The New York Times. Retrieved 2007-07-17.
  31. ↑ Practitioners, The Royal Australian College of General. "RACGP - Evidence based exercise – clinical benefits of high intensity interval training". www.racgp.org.au. Retrieved 2016-10-25.
  32. ↑ East Tennessee State University Thesis Archived March 19, 2007, at the Wayback Machine.

References

  • Cooper, Kenneth C. The New Aerobics. Eldora, Iowa: Prairie Wind.
  • Donatelle, Rebecca J. Health: The Basics. 6th ed. San Francisco: Pearson Education, Inc. 2005.
  • Hinkle, J. Scott. School Children and Fitness: Aerobics for Life. Ann Arbor, MI: ERIC
  • Clearinghouse on Counseling and Personnel Services.
  • Aberg MA, Pedersen NL, Torén K, Svartengren M, Bäckstrand B, Johnsson T, Cooper-Kuhn CM, Aberg ND, Nilsson M, & Kuhn HG. (2009) Cardiovascular fitness is associated with cognition in young adulthood. Proceedings of the National Academy of Sciences of the United States of America.
  • Guiney, Hayley & Machado, Liana. Benefits of regular exercise for executive functioning in healthy populations. Psychon. Bull. Rev. 2013.
  • Rendi, Maria, Szabo, Atila, Szabo, Tomas, Velenczei, Attila & Kovas, Arpad. Acute psychological benefits of aerobic exercise: A field study into the effects of exercise characteristics. Psychol, Health. Med. 2008.
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