Aerobic, anaerobic exercise

Aerobic exercise

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Aerobic exercise refers to exercise that is of moderate intensity, undertaken for a long duration. Aerobic means "with oxygen", and refers to the use of oxygen in a muscle's energy-generating process. Many types of exercise are aerobic, and by definition are performed at moderate levels of intensity for extended periods of time.

An effective aerobic exercise should involve 5-10 minutes of warming up at an intensity of 50-60% of maximum heart rate, followed by at least 20 minutes of exercise at an intensity of 70-80% of maximum heart rate, ending with 5-10 minutes of cooling down at an intensity of 50-60% of maximum heart rate. ^{[citation needed]}

[edit] History

Both the term and the exercise method were developed by Kenneth H. Cooper, M.D., an exercise physiologist, and Col. Pauline Potts, a physical therapist, both of the Air Force. Dr. Cooper, an avowed exercise enthusiast, was personally and professionally puzzled about why some people with excellent muscular strength were still prone to poor performance at tasks such as long-distance running, swimming, and bicycling. He began measuring systematic human performance using a bicycle ergometer, and began measuring sustained performance in terms of the ability to utilize oxygen.

His groundbreaking book, Aerobics, was published in 1968, and included scientific exercise programs using running, walking, swimming and bicycling. The book came at a fortuitous historical moment, when increasing weakness and inactivity in the general population was causing a perceived need for increased exercise. It became a best seller.

Cooper's data provided the scientific baseline for almost all modern aerobics programs, most of which are based on oxygen-consumption equivalency.

[edit] 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 weight training 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.

Initially during aerobic exercise, glycogen is broken down to produce glucose, but in its absence, fat metabolism is initiated instead. The latter is a slow process, and is accompanied by a decline in performance level. The switch to fat as fuel is a major cause of what marathon runners call "hitting the wall".

Anaerobic exercise, in contrast, refers to the initial phase of exercise, or any short burst of intense exertion, in which the glycogen or sugar is consumed without oxygen, and is a far less efficient process. Operating anaerobically, an untrained 400 meter sprinter may "hit the wall" short of the full distance.

There are various types of aerobic exercise. In general, aerobic exercise is one performed at a low to moderate level of intensity over a 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 doubles tennis, with their brief bursts of activity punctuated by more frequent breaks, may not be predominantly aerobic.

Among the recognized 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
• Toning muscles throughout the body, which can improve overall circulation and reduce blood pressure
• Increasing the total number of red blood cells in the body, to facilitate transport of oxygen throughout the body

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 jumping rope) can stimulate bone growth, as well as reducing the risk of osteoporosis for both men and women.

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

• Increased 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

[edit] Aerobic exercise versus aerobics

"Aerobics" are a particular form of aerobic exercise. Aerobics classes generally involve rapid stepping patterns, performed to music with cues provided by an instructor. This type of aerobic activity became quite popular in the United States after the 1970 publication of The New Aerobics by Dr. Kenneth H. Cooper, and went through a brief period of intense popularity in the 1980s, when many celebrities (such as Jane Fonda and Richard Simmons) produced videos or created television shows promoting this type of aerobic exercise. Group exercise aerobics can be divided into two major types: Freestyle Aerobics and Pre-choreographed aerobics.

[edit] Aerobic capacity

'Aerobic capacity' describes the functional status of the cardiorespiratory system, (the heart, lungs and blood vessels). Aerobic capacity is defined as the maximum volume of oxygen that can be consumed by one's muscles during exercise. It is a function both of one's cardiorespiratory performance and of the ability of the muscles to extract the oxygen and fuel delivered to them. 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 hooked up to a respirometer to measure oxygen, and the speed is increased incrementally over a fixed duration of time. The higher a cardiorespiratory endurance level, the more oxygen transported to exercising muscles, the longer exercise can be maintained without exhaustion and accordingly the faster they are able to run. The higher aerobic capacity, the higher the level of aerobic fitness. The Cooper and multi-stage fitness tests can also be used to functionally assess aerobic capacity. In most people, aerobic capacity can be improved through a variety of means, including Fartlek training.

The degree to which aerobic capacity can be improved by exercise varies very widely in the human population: while the mean 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.^[1] Studies indicate that approximately 10% of otherwise healthy individuals cannot improve their aerobic capacity with exercise at all.^[2] The degree of an invididual's responsiveness is highly heritable, suggesting that this trait is genetically determined.^[1]

[edit] Criticisms

When generalized fitness is a professional operational requirement, as for athletes, combat services, police and fire personnel, aerobic exercise alone may not provide a well-balanced exercise program. In particular, muscular strength, especially upper-body muscular strength, is usually neglected. Also, the metabolic pathways involved in anaerobic metabolism (glycolysis and lactic acid fermentation) that generate energy during high intensity, low duration tasks such as sprinting, are not exercised at peak rates. Aerobic exercise is, however, an extremely valuable component of a balanced exercise program and is good for cardiovascular health.^{[citation needed]}

Some persons suffer repetitive stress injuries with some forms of aerobics and then must choose less injurious "low-impact" forms or lengthen the gap between bouts of aerobic exercise to allow for greater recovery.

Aerobics notably does not increase the resting metabolic rate as much as some forms of weight-training, and may therefore be less effective at reducing obesity. However, this form of exercise also allows for longer, more frequent activity and consumes more energy when the individual is active. In addition, the metabolic activity of an individual is heightened for several hours following a bout of aerobic activity.

Aerobic activity is also used by individuals with anorexia as a means of suppressing appetite, since aerobic exercise increases glucose and fatty acids in the blood by stimulating tissues to release their energy stores. While there is some support for exercising while hungry as a means of tapping into fat stores, most evidence is equivocal. In addition, performance can be impaired by lack of nutrients, which can impair training effects.

[edit] Commercial success

Aerobic exercise has long been a popular form of weight loss and physical fitness, often taking a commercial form.

• Tennis and jogging gained prominence and popularity in the 1970s
• Judi Sheppard Missett largely helped create the market for commercial aerobics with her Jazzercise program in the 1970s
• Richard Simmons hosted an aerobic exercise show on television, beginning in the 1980s, and continued with a variety of exercise videos.
• Billy Blanks's Tae Bo helped popularize cardio-boxing, workouts that used martial arts movements in the 1990s
• The Nia Technique, also called Neuromuscular Integrative Action, was developed in the 1980s as a form of "non-impact" aerobics (the original words in the acronym). This is in contrast to popular "no pain no gain" attitudes, and attempted to combat the problem of impact injuries.

 

 

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Anaerobic exercise

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Anaerobic exercise is typically used by athletes in non-endurance sports to build power and by body builders to build muscle mass. Muscles that are trained under anaerobic conditions develop biologically differently giving them greater performance in short duration-high intensity activities.

Aerobic exercise, on the other hand, includes lower intensity activities performed for longer periods of time. Activities like walking, running, swimming, and cycling require a great deal of oxygen to generate the energy needed for prolonged exercise.

There are two types of anaerobic energy system, the ATP-PCr energy system, which uses creatine phosphate as the main energy source, and the lactic-acid (or anaerobic glycolysis) system that uses glucose (or glycogen) in the absence of oxygen. The latter is an inefficient use of glucose and produces by-products that are thought to be detrimental to muscle function. The lactic-acid system is the dominant energy system during high to maximal intensity exercise over short durations (up to about 1 min), but the lactic acid system can still provide a proportion of the required energy during aerobic exercise, as the body has the capacity to get rid of the anaerobic by-products at a certain rate. The efficiency of by-product removal by muscles can improve through training.

[edit] Anaerobic biochemistry

Main articles: Fermentation (biochemistry) and Anaerobic respiration

Anaerobics are activities that are carried out 'without oxygen'. This terminology refers to the molecular level of respiration, not the respiration of the organism as a whole (i.e., breathing). During anaerobic exercise, the muscles being exercised have insufficient oxygen to meet the demands of the activity, and thus must also use alternate, non-oxygen-dependent processes to produce energy. The muscle does still receive oxygen during anaerobic exercise; the average drop in blood oxygen content throughout the body is likely minimal.

Anaerobic exercise begins with muscles utilizing stored creatine phosphate to generate the ATP that produces muscle contraction. After several seconds, further ATP energy is made available to muscles by metabolizing muscle glycogen into pyruvate through glycolysis, as it normally does through the aerobic cycle. What differs is that pyruvate, rather than be broken down through the slower but more energy efficient aerobic process, is fermented to lactic acid.

Muscle glycogen is restored from blood sugar, which comes from the liver, from digested carbohydrates, or from amino acids which have been turned into glucose.

[edit] Lactate threshold (Now called LIP or Lactate Inflection Point)

The lactate threshold (LT) is the exercise intensity at which lactic acid starts to accumulate in the blood stream. This happens when it is produced faster than it can be removed (metabolized). This point is sometimes referred to as the anaerobic threshold (AT), or the onset of blood lactate accumulation (OBLA). When exercising below the LT intensity any lactate produced by the muscles is removed by the body without it building up.

The lactate threshold is a useful measure for deciding exercise intensity for training and racing in endurance sports (e.g. distance running, cycling, rowing, swimming and cross country skiing), and can be increased greatly with training.

Fartlek (speed-play) training and interval training take advantage of the body being able to temporarily exceed the lactate threshold, and then recover (reduce blood-lactate) while operating at below the threshold, but still doing physical activity. Fartlek and interval training are similar, the main difference being the relative intensities of the exercise, best illustrated in a real-world example: Fartlek training would involve constantly running, for a period time running just above the lactate threshold, and then running at just below it, while interval training would be running quite high above the threshold, but then slowing to a walk or slow jog during the rest periods.

Fartlek would be used by people who are constantly moving, with occasional bouts of speed, such as basketballers, while interval training is more suited to sprinters, who exert maximum effort and then can stop exerting completely. With both styles of training, one can exert more effort before fatiguing and burn more calories than exercising at a constant pace (continuous training), but will emphasize training the anaerobic system rather than the aerobic system. Long duration training below the lactate threshold is recommended to primarily work the aerobic system.

Accurately measuring the lactate threshold involves taking blood samples (normally a pinprick to the finger, earlobe or thumb) during a ramp test where the exercise intensity is progressively increased. Measuring the threshold can also be performed non-invasively using gas-exchange (Respiratory quotient) methods, which requires a metabolic cart to measure air inspired and expired.

Although the lactate threshold is defined as the point when lactic acid starts to accumulate, some testers approximate this by using the point at which lactate reaches a concentration of 4 mM (at rest it is around 1 mM)....

 

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유산소운동 [有酸素運動, aerobic exercise]

요약

편안한 호흡을 지속하면서 할 수 있는 운동.

본문

에어로빅스(Aerobics), 에어로빅운동이라고도 한다. 숨이 차지 않으며 큰 힘을 들이지 않고도 할 수 있는 운동으로 몸 안에 최대한 많은 양의 산소를 공급시킴으로써 심장과 폐의 기능을 향상시키고 강한 혈관조직을 갖게 하는 효과가 있다. 따라서, 장기간에 걸쳐 규칙적으로 실시하면 운동 부족과 관련이 높은 고혈압, 동맥경화, 고지혈증, 허혈성 심장질환, 당뇨병 등의 성인병을 적절히 예방할 수 있을 뿐만 아니라, 비만 해소와 노화 현상을 지연시킬 수 있다. 조깅, 달리기, 수영, 자전거타기, 에어로빅댄스, 크로스컨트리, 마라톤 등이 여기에 속한다.

1968년 미국의 심장병 전문의인 케네스 쿠퍼(Kenneth Cooper)가 심장병 치료를 위한 운동 요법으로 고안하였는데, 미국항공우주국에서 우주비행사의 신체적성 프로그램으로 이용되어 큰 호응을 얻은 뒤부터 민간단체의 예방의학적 차원에서 대중운동으로 실시하게 되었다. 국내에는 1974년 2월 YMCA(Young Men's Christian Association:기독교청년회) 초청으로 내한한 쿠퍼 박사가 워크숍을 통해 소개하면서 보급되었다. 현재 많은 운동 종목에서 심폐 지구력 강화 프로그램에 활용된다.

운동을 심하게 하지 않으면서도 근육을 적당히 수축·이완시켜 최대의 효과를 거두려면 운동 강도, 운동 지속시간, 운동 빈도 등이 고려되어야 한다. 운동 강도는 최대운동능력의 40∼85％ 범위에서 처방한다. 일반적으로 건강한 성인은 60∼80％ 범위에서, 최대운동능력이 낮거나 운동을 처음 시작하는 사람은 40∼60％ 범위 내에서 운동을 시작하는 것이 좋다.

운동 시간은 운동 강도에 따라 다르게 정한다. 일반적으로 준비 운동과 정리 운동을 제외하고 1회에 15∼60분 정도가 적당하다. 미국 스포츠의학회는 초기 운동 강도를 선택할 경우, 20∼30분 지속할 수 있는 운동 강도와 운동 시간을 권하고 있다.

운동 빈도는 각 개인의 건강과 체력 수준에 달려 있다. 정상 성인의 경우 최소한 일주일에 3회 정도는 운동을 해야 심폐 지구력이 향상되는데 체력 수준이 높아지면 5회 정도로 늘려야 심폐 지구력의 지속적인 향상을 기대할 수 있다. 최대운동능력이 낮은 사람은 1회 운동 시간을 5분 정도로 하여 하루에 3∼4회 정도로 나누어서 하는 것이 좋다. 운동 빈도를 주 5회 이상으로 할 경우에는 걷기, 달리기 등 체중 부담을 안고 하는 운동과 수영, 자전거타기 등 체중 부담이 없는 운동을 번갈아 실시하는 것이 좋다.

무산소운동 [無酸素運動, anaerobic exercise]

요약

힘이 들고 숨이 차서 오래 지속할 수 없는 형태의 운동.

본문

언에어로빅스, 언에어로빅 운동이라고도 한다. 운동을 할 때 숨이 찬다는 말은 운동에 필요한 산소가 부족하다는 뜻을 나타낸다. 무산소 운동은 산소가 충분하지 않거나 없는 상태에서 이루어져서 숨이 차고 힘이 들어 길어야 2, 3분 정도밖에 지속할 수 없는 단시간 운동이다. 테니스·배구 등의 서브나 스파이크, 단거리달리기, 팔굽혀펴기, 던지기경기, 도약경기, 씨름, 잠수, 역도 등이 여기에 속한다.

산소 섭취량이 운동시 필요한 ATP를 공급하는 데 소요되는 산소량에 미치지 못하기 때문에 이 기간 동안에는 운동에 필요한 대부분의 ATP를 공급하기 위해 ATP-CP와 젖산 시스템(해당계)이 작용한다.

해당작용에 필요한 글루코오스를 공급하는 저장된 글리코겐이 이용될 때 근육과 혈액 내에 젖산이 쌓이게 된다. 산소가 부족한 상태에서 젖산 함량이 많아지면 젖산이 산화되지 못하므로 글리코겐이 재합성되지 못하게 된다. 결국 글리코겐 저장량이 고갈되는데 이것은 근수축에 필요한 연료가 떨어졌음을 의미한다. 이러한 변화가 피로의 원인이 되어 운동을 중지하거나 운동 강도를 줄이게 한다. 그러므로 높은 젖산 함량을 견디는 능력과 피로감을 참는 것이 대부분의 운동 경기를 승리로 이끄는 선행 조건이 된다.