Exercises are generally grouped into three types depending on the overall effect they have on the human body:
- Aerobic exercises, such as cycling, walking, running, hiking, and playing tennis, focus on increasing cardiovascular endurance.1
- Anaerobic exercises, such as weight training, increase short-term muscle strength.2
- Flexibility exercises such as stretching improve the range of motion of muscles and joints.3
Aerobic and anaerobic are the most commonly performed, so here is an overview of their qualities:
Aerobic (or cardiovascular exercise, a term attributed to this kind of exercise because of its various benefits in cardiovascular health) refers to exercise that involves or improves oxygen consumption by the body.4 Aerobic means "with oxygen", and refers to the use of oxygen in the body's metabolic or energy-generating process.5 Many types of exercise are aerobic, and by definition are performed at moderate levels of intensity for extended periods of time. This intensity can vary from 50-80% of maximum heart rate.
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 tennis, with near-continuous motion, is generally considered aerobic activity, while 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:
- Stronger heart: the heart muscle is strengthened and enlarged, to improve its pumping efficiency and reduce the resting heart rate.
- Increase of the total number of red blood cells in the body, to facilitate transport of oxygen throughout the body
- Improved breathing: the muscles involved in respiration are strengthened, to facilitate the flow of air in and out of the lungs.
- Improved muscle health: Aerobic exercise stimulates the growth of tiny blood vessels (capillaries) in muscles. This helps our bodies more efficiently deliver oxygen to muscles, can improve overall circulation and reduce blood pressure and remove irritating metabolic waste products such as lactic acid from the muscles.
- Weight loss: Combined with a healthy diet and appropriate strength training, aerobic exercise may help lose weight.
- Disease reduction: Extra weight is a contributing factor to conditions such as heart disease, high blood pressure, stroke, diabetes and some forms of cancer. As weight loss occurs, the risk of developing these diseases decreases. In addition, weight-bearing aerobic exercise, such as walking, can reduce the risk of osteoporosis and its complications. Low-impact aerobic exercises, such as swimming, cycling and pool exercises, can help keep fit in those who have arthritis, without putting excessive stress on joints.
- Improved immune system: People who exercise regularly are less susceptible to minor viral illnesses such as colds and flu. It is possible that aerobic exercise helps activate your immune system and prepares it to fight off infection.
- Improved mental health: Regular aerobic exercise releases endorphins, our bodies’ natural painkillers. Endorphins also reduce stress, depression and anxiety.
- Increased stamina: Exercise may make us feel tired in the short term, i.e., during and right after the activity, but over the long term it will increase stamina and reduce fatigue.
Anaerobic exercise is the type of exercise that enhances power and builds muscle mass. Muscles trained under anaerobic conditions develop differently, leading to greater performance in short duration, high intensity activities, which last up to about 2 minutes.6
The most common form of anaerobic exercise is strength exercise. Strength exercise is the use of resistance to muscular contraction to build the strength, anaerobic endurance and size of skeletal muscles. There are many different methods of strength training, the most common of which are weight and resistance exercise. These two types of exercise use gravity (through weight stacks, plates or dumbells) or machines to oppose muscle contraction, and the terms can be used interchangeably.
When properly performed, strength training can provide significant functional benefits and improvement in overall health and well-being including increased bone, muscle, tendon and ligament strength, toughness and endurance, improved joint function, reduced potential for injury resulting from weak muscles, improved cardiac function and elevated “good” HDL-cholesterol. It can also help maintain lean body mass (important for individuals attempting weight loss), decrease the risk of osteoporosis, develop coordination and balance.
Aerobic vs Anaerobic
Frequent and regular aerobic exercise has been shown to help prevent or treat serious and life-threatening chronic conditions such as high blood pressure, obesity, heart disease, Type 2 diabetes, insomnia, and depression. Strength training appears to have continuous energy-burning effects that persist for about 24 hours after the training, though they do not offer the same cardiovascular benefits of aerobic exercises. Both aerobic and anaerobic exercise also work to increase the mechanical efficiency of the heart by increasing cardiac volume (aerobic exercise), or myocardial thickness (strength training).
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.
Aerobics notably does not increase the basal 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.
Not everyone benefits equally from the different types of exercise . There is tremendous variation in individual response to exercise: where most people will see a moderate increase in endurance from aerobic exercise, some individuals will as much as double their oxygen uptake, while others will never get any benefit at all from the exercise.7 Similarly, only a minority of people will show significant muscle growth after prolonged weight training, while a larger fraction experience improvements in strength.8 This is why people should experiment and try different types of physical activity, so that they can find what type they really like and what works for them.
The bottom line when undertaking an aerobic or an anaerobic exercise program is that you must be careful and responsible. Both may provide the type of vigorous workout that you require. So listen to your body and exercise your common sense as well as your muscles.
Suddenly going from being completely sedentary to rushing out for a four mile jog or being forced to do a school sport that you loathed would be enough to put anyone off. Yet if you find a form of activity that suits your body and take it at the right pace, far from hurting, working up a sweat stimulates the release of chemicals in the body that make you feel good. But before you head for the treadmill or put on your trainers for a run round the park, read on, because the benefits of regular exercise don't end there.
1 Wilmore, J., Knuttgen, H. 2003. Aerobic Exercise and Endurance Improving Fitness for Health Benefits. The Physician and Sportsmedicine, 31(5). 45. Retrieved October 5, 2006, from ProQuest database.
2 de Vos, N., Singh, N., Ross, D., Stavrinos, T., et al. 2005. Optimal Load for Increasing Muscle Power During Explosive Resistance Training in Older Adults. The Journals of Gerontology, 60A(5), 638-647. Retrieved October 5, 2006, from ProQuest database.
3 O'Connor, D., Crowe, M., Spinks, W. 2006. Effects of static stretching on leg power during cycling. Turin, 46(1), 52-56. Retrieved October 5, 2006, from ProQuest database.
4 http://education.yahoo.com/reference/dictionary/entry/aerobic;_ylt=AmqtTKeFBRk1W31mkNOeQX2sgMMF. Accessed on 30th June 2008.
5 http://en.wikipedia.org/wiki/Aerobic_organism. Accessed on 30th June 2008.
6 http://www.asmi.org/sportsmed/Performance/anaerobic.html. Accessed on 30th June 2008.
7 Bouchard, Claude; Ping An, Treva Rice, James S. Skinner, Jack H. Wilmore, Jacques Gagnon, Louis Perusse, Arthus S. Leon, D. C. Rao (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. PMID 10484570. Retrieved on July 17, 2007
8 Hubal, MJ; Gordish-Dressman H, Thompson PD, Price TB, Hoffman EP, Angelopoulos TJ, Gordon PM, Moyna NM, Pescatello LS, Visich PS, Zoeller RF, Seip RL, Clarkson PM (June 2005). "Variability in muscle size and strength gain after unilateral resistance training.". Medicine and Science in Sports and Exercise 37 (6): 964-972. PMID 15947721. Retrieved on July 17, 2007.