Exercise

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Exercise is "physical activity which is usually regular and done with the intention of improving or maintaining physical fitness or health."[1]

Types of physical activities

Usual daily activities

General physical activities may be defined in terms of the intensity levels [2].

"Neighborhood physical and social environmental factors are significantly associated with walking at recommended levels."[3]

Signs placed in public places where steps are available may increase usage of the stairs.[4][5][6]

Moderate to high intensity exercise

(in progress)

Metabolism and energy

Oxygen consumption

For more information, see: Metabolic equivalent.


Energy consumption

The amount of energy expended with exercise, or the work, is measured in calories. Using running as an example:

In running, work is directly dependent on:

  • Body weight
  • Duration

Work is indirectly dependent on:

  • Speed

Effects of exercise

Effects on Hypertension

Exercise programs that primarily involve endurance activities prevent the development of hypertension and lower blood pressure (BP) in adults with normal BP and those with hypertension [7].

Insulin sensitivity

(in progress)

Insulin production

Aerobic exercise was shown to increase beta cell function in older persons, in whom both insulin production and insulin sensitivity are frequently impaired.[8]

Mood and cognition

The effects of exercise on mood and mental functioning, described by the latin quotation Mens sana in corpore sano (a healthy mind in a healthy body), are profound. Research attempting to isolate the biochemical nature of this relationship showed that the access to the brain of the insulin-like growth factor I (IGF-1), which is stimulated by physical activity, could explain much of the beneficial effects of exercise.[9] It is apparent that exercise lessens anxiety and increases cognitive skills by stimulating the birth of new neurons, neurogenesis, in the hippocampus, and that this process is in large part mediated by IGF-1.[10]

As little as 20 minutes of exercise per week is associated with improved mental health.[11]

Exercise may reduce anxiety.[12]

Harm reduction

Considering the magnitude of the health effects of exercise, it is justified to enquire if this strategy can act as protective measure against the harm associated with a variety of unhealthy practices that patients are unable or unwilling to abandon. Harm reduction is a pragmatic approach to medical and psychological care that seeks to address the needs of such persons, instead of focussing only on coercitive and poorly effective approaches to unhealthy behaviours, most notably addictions. It appears that engaging in higher physical activities neutralizes many of the deleterious effects of tobacco smoking.[13] Tobacco addiction in itself leads to a tendency to physical inactivity, a fact that should reinforce the need to investigate the health effects of exercise and promote its value in tobacco addiction, the major cause of lung cancer.

Mortality

Physical fitness, as measured by maximal treadmill exercise test duration, correlates with longevity in the elderly[14] as well as both longevity and functional status.[15]

Promoting exercise

Methods of promotion cycling have been reviewed.[16]

Use of a pedometer is "associated with significant increases in physical activity and significant decreases in body mass index and blood pressure" according to a systematic review.[17]

References

  1. National Library of Medicine. Exercise. Retrieved on 2007-10-19.
  2. Exercise Categories. Retrieved on 2008-02-12.
  3. Wen M, Kandula NR, Lauderdale DS (2007). "Walking for Transportation or Leisure: What Difference Does the Neighborhood Make?". DOI:10.1007/s11606-007-0400-4. PMID 17932724. Research Blogging.
  4. Andersen RE, Franckowiak SC, Snyder J, Bartlett SJ, Fontaine KR (1998). "Can inexpensive signs encourage the use of stairs? Results from a community intervention". Ann. Intern. Med. 129 (5): 363–9. PMID 9735063[e]
  5. Webb OJ, Eves FF (2007). "Promoting stair climbing: intervention effects generalize to a subsequent stair ascent". Am J Health Promot 22 (2): 114–9. PMID 18019888[e]
  6. Webb OJ, Eves FF (2007). "Promoting stair climbing: effects of message specificity and validation". Health Educ Res 22 (1): 49–57. DOI:10.1093/her/cyl045. PMID 16763074. Research Blogging.
  7. Pescatello LS, Franklin BA, Fagard R, Farquhar WB, Kelley GA, Ray CA (2004). "American College of Sports Medicine position stand. Exercise and hypertension". Med Sci Sports Exerc 36 (3): 533–53. PMID 15076798[e]
  8. Bloem CJ, Chang AM (2007). "Short-term Exercise Improves {beta}-cell Function and Insulin Resistance in Older People with Impaired Glucose Tolerance". DOI:10.1210/jc.2007-1734. PMID 18000089. Research Blogging.
  9. Carro E, Nuñez A, Busiguina S, Torres-Aleman I (2000). "Circulating insulin-like growth factor I mediates effects of exercise on the brain". J. Neurosci. 20 (8): 2926–33. PMID 10751445[e]
  10. Trejo JL, Llorens-Martín MV, Torres-Alemán I (2007). "The effects of exercise on spatial learning and anxiety-like behavior are mediated by an IGF-I-dependent mechanism related to hippocampal neurogenesis". Mol Cell Neurosci. DOI:10.1016/j.mcn.2007.10.016. PMID 18086533. Research Blogging.
  11. Mark Hamer, Emmanual Stamatakis, and Andrew Steptoe, “Dose response relationship between physical activity and mental health: The Scottish Health Survey,” Br J Sports Med (April 10, 2008): DOI:bjsm.2008.046243.
  12. Herring MP, O'Connor PJ, Dishman RK (2010). "The effect of exercise training on anxiety symptoms among patients: a systematic review.". Arch Intern Med 170 (4): 321-31. DOI:10.1001/archinternmed.2009.530. PMID 20177034. Research Blogging.
  13. deRuiter W, Faulkner G (2006). "Tobacco harm reduction strategies: the case for physical activity". Nicotine Tob. Res. 8 (2): 157–68. DOI:10.1080/14622200500494823. PMID 16766410. Research Blogging.
  14. Xuemei Sui et al., “Cardiorespiratory Fitness and Adiposity as Mortality Predictors in Older Adults,” JAMA 298, no. 21 (December 5, 2007), http://jama.ama-assn.org/cgi/content/abstract/298/21/2507 (accessed December 5, 2007).
  15. Laurel B. Yates et al., “Exceptional Longevity in Men: Modifiable Factors Associated With Survival and Function to Age 90 Years,” Arch Intern Med 168, no. 3 (February 11, 2008): 284-290. http://archinte.ama-assn.org/cgi/content/abstract/168/3/284
  16. Yang L, Sahlqvist S, McMinn A, Griffin SJ, Ogilvie D (2010). "Interventions to promote cycling: systematic review.". BMJ 341: c5293. DOI:10.1136/bmj.c5293. PMID 20959282. PMC PMC2957539. Research Blogging.
  17. Bravata DM, Smith-Spangler C, Sundaram V, et al (2007). "Using pedometers to increase physical activity and improve health: a systematic review". JAMA 298 (19): 2296–304. DOI:10.1001/jama.298.19.2296. PMID 18029834. Research Blogging.