Portal de Periódicos da CAPES

Exercise: A Walk in the Park?

2007; Elsevier BV; Volume: 82; Issue: 7 Linguagem: Inglês

10.4065/82.7.797

1942-5546

James A. Levine,

Cancer survivorship and care

In this issue of Mayo Clinic Proceedings,1Nemoto K Gen-no H Masuki S Okazaki K Nose H Effects of high-intensity interval walking training on physical fitness and blood pressure in middle-aged and older people.Mayo Clin Proc. 2007; 82: 803-811Abstract Full Text Full Text PDF PubMed Scopus (154) Google Scholar Nemoto et al address the benefits of walking regimens and in so doing reflect a broad movement in the exercise literature and the health intervention community. Emphasis is moving away from in-termittent sweat-drenched bouts of arduous exercise to more frequent walking, whether in the park, at work, or at home. Over the past 50 years, the core messages of publications in exercise physiology have evolved similarly to those of other societal movements. Two generations ago, the notion that people would pay thousands of dollars or Euros each year to sweat and feel the pain of extreme physical exertion would have been viewed as untenable. However, the exercise movement emerged, and scientists and celebrities ran hand in hand to the gymnasium. During this time, the message conveyed by exercise literature was “more is better.” The oft-quoted surgeon general's report2National Center for Chronic Disease Prevention and Health Promotion 1996 Physical Activity and Health: A Report of the Surgeon General. US Dept of Health and Human Services, Centers for Disease Control and Prevention, Atlanta, Ga1996Google Scholar well summarizes the notion that more exercise of greater intensity promises more health of greater duration. The heated debates as to whether aerobic exercise has more health benefits than strength training3Blair SN LaMonte MJ Nichaman MZ The evolution of physical activity recommendations: how much is enough?.Am J Clin Nutr. 2004; 79: 913S-920SPubMed Google Scholar have quieted with the growing recognition that all exercise is good, and more of it is better.4Karmisholt K Gotzsche PC Physical activity for secondary prevention of disease: systematic reviews of randomised clinical trials.Dan Med Bull. 2005; 52: 90-94PubMed Google Scholar It is interesting that the exercise movement evolved similarly to other emotional societal movements such as those addressing racial intolerance5Shavers VL Shavers BS Racism and health inequity among Americans.J Natl Med Assoc. 2006; 98: 386-396PubMed Google Scholar, 6Teitelbaum JB Health care and civil rights: an introduction.Ethn Dis. Spring 2005; 15: S27-S30PubMed Google Scholar and homosexual discrimination.7Meyer IH Prejudice, social stress, and mental health in lesbian, gay, and bisexual populations: conceptual issues and research evidence.Psychol Bull. 2003; 129: 674-697Crossref PubMed Scopus (7332) Google Scholar In those movements too, initial vehement cries for action and debate among the scientific, intellectual, and political communities as to how best to proceed gave way to consensus and action.8Sartorelli J. Gay rights and affirmative action. J Homosex, 27:179–222.Google Scholar Nemoto et al report that walking training in middle-aged and older people bestows health benefits that are akin to those provided by a gymnasium exercise program. This article is 1 of many that speak to the health benefits associated with walking, whether the outcome measurement is blood pressure,9Kokkinos PF Narayan P Papademetriou V Exercise as hypertension therapy.Cardiol Clin. 2001; 19: 507-516Abstract Full Text Full Text PDF PubMed Scopus (77) Google Scholar as in this article, diabetes,10Smith TC Wingard DL Smith B Kritz-Silverstein D Barrett-Connor E Walking decreased risk of cardiovascular disease mortality in older adults with diabetes.J Clin Epidemiol. 2007 Mar; 60 (Epub 2006 Oct 2.): 309-317Abstract Full Text Full Text PDF PubMed Scopus (91) Google Scholar other metabolic disorders,11Boardley D Fahlman M Topp R Morgan AL McNevin N The impact of exercise training on blood lipids in older adults.Am J Geriatr Cardiol. 2007; 16: 30-35Crossref PubMed Scopus (43) Google Scholar cardiovascular disease,12Albright C Thompson DL The effectiveness of walking in preventing cardiovascular disease in women: a review of the current literature.J Womens Health (Larchmt). 2006; 15: 271-280Crossref PubMed Scopus (51) Google Scholar joint problems, or mental health (Figure 1).13Larun L Nordheim LV Ekeland E Hagen KB Heian F Exercise in prevention and treatment of anxiety and depression among children and young people.Cochrane Database Syst Rev. 2006; 3 (CD004691)PubMed Google Scholar Collectively, these data suggest that, regardless of the study population, walking improves health. This information complements physiological studies that document the role played by inactivity or sedentariness in poor health14Rosal MC Ockene JK Ma Y et al.Behavioral risk factors among members of a health maintenance organization.Prev Med. 2001; 33: 586-594Crossref PubMed Scopus (47) Google Scholar and in the pathogenesis of obesity.15Dietz W Physical activity and childhood obesity.Nutrition. 1991; 7: 295-296PubMed Google Scholar, 16Levine JA Nonexercise activity thermogenesis (NEAT): environment and biology [published correction appears in Am J Physiol Endocrinol Metab. 2005;288:E285].Am J Physiol Endocrinol Metab. 2004; 286: E675-E685Crossref PubMed Scopus (137) Google Scholar, 17Levine JA Lanningham-Foster LM McCrady SK et al.Interindividual variation in posture allocation: possible role in human obesity.Science. 2005; 307: 584-586Crossref PubMed Scopus (539) Google Scholar The growing body of scientific information regarding the health benefits of walking18Morris JN Hardman AE Walking to health [published correction appears in Sports Med. 1997;24:96].Sports Med. 1997; 23: 306-332Crossref PubMed Scopus (456) Google Scholar and of reversing sedentariness is mirrored by a growing public interest in walking as a means of exercise and health. See also page 803 What is one to make of the mounting evidence of the health benefits of walking in light of data from the exercise movement showing the benefits of high-intensity, high-level exertion? This apparent quandary can be resolved. First, individuals who are able to undertake and sustain high-duration, high-intensity exercise are, by definition, healthier than the population who rarely exercises; long-distance cyclists are inevitably healthier than people who only occasionally walk in the park. Second, emerging evidence indicates that a great deal of low-intensity activity can have as many health and physiological benefits as high-intensity exercise.19Blair SN Brodney S Effects of physical inactivity and obesity on morbidity and mortality: current evidence and research issues.Med Sci Sports Exerc. 1999; 31: S646-S662Crossref PubMed Scopus (104) Google Scholar For example, if an office worker with elevated plasma triglycerides (eg, familial hypertriglyceridemia) goes to the gym and runs for 30 minutes at 5 mph, his or her triglyceride levels will decrease to normal values for the duration of the exercise and for approximately 1½ hours afterward.20Katsanos CS Prescribing aerobic exercise for the regulation of postprandial lipid metabolism: current research and recommendations.Sports Med. 2006; 36: 547-560Crossref PubMed Scopus (44) Google Scholar, 21Kimber NE Heigenhauser GJ Spriet LL Dyck DJ Skeletal muscle fat and carbohydrate metabolism during recovery from glycogen-depleting exercise in humans.J Physiol. 2003 May 1; 548 (Epub 2003 Mar 21.): 919-927Crossref PubMed Scopus (75) Google Scholar Conversely, if the same office worker walks for 30 minutes of each hour throughout the workday, his or her triglyceride levels will also decrease during and after each walk, although not to the same degree as during a 5 mph run. However, because the walking occurs throughout the day, the cumulative daylong decrease in blood triglycerides is greater than that seen after a single bout of running.22Hamilton MT Hamilton DG Zderic TW Exercise physiology versus inactivity physiology: an essential concept for understanding lipoprotein lipase regulation.Exerc Sport Sci Rev. 2004; 32: 161-166Crossref PubMed Scopus (288) Google Scholar Third, walking is accessible to many more people than high-intensity exercise both in tolerance and cost. Fourth and importantly, walking exposes participants to few activity-associated injuries,23Jilcott SB Laraia BA Evenson KR Lowenstein LM Ammerman AS A guide for developing intervention tools addressing environmental factors to improve diet and physical activity.Health Promot Pract. 2007; 8: 192-204Crossref PubMed Scopus (30) Google Scholar whereas nearly all high-intensity athletes experience sports-associated injuries.24Elliott MC Wagner PP Chiu L Power athletes and distance training: physiological and biomechanical rationale for change.Sports Med. 2007; 37: 47-57Crossref PubMed Scopus (30) Google Scholar Overall, the critical health benefit may be derived from the displacement of sedentariness by activity.25Zderic TW Hamilton MT Physical inactivity amplifies the sensitivity of skeletal muscle to the lipid-induced downregulation of lipoprotein lipase activity.J Appl Physiol. 2006 Jan; 100 (Epub 2005 Sep 29.): 249-257Crossref PubMed Scopus (109) Google Scholar The longer a person is active, the better, regardless of what form that activity takes. In conclusion, humans evolved to walk upright over the past million years.26Orr CM Knuckle-walking anteater: a convergence test of adaptation for purported knuckle-walking features of African Hominidae.Am J Phys Anthropol. 2005; 128: 639-658Crossref PubMed Scopus (52) Google Scholar Over the past 200,000 years, people populated the earth by walking across it. Our bodies evolved to walk.27Morgan E Bipedalism.Nutr Health. 1993; 9: 193-203Crossref PubMed Scopus (3) Google Scholar As recent as 150 years ago, 90% of the world's population lived in agricultural regions,28UN-Habitat State of the World's Cities 2004/2005: Globalization and Urban Culture. United Nations Human Settlements Programme (Habitat), New York, NY2004Google Scholar and, like our distant ancestors, walked to work, physically exerted themselves at work, and walked home at the end of the day. Water carriage, food preparation, and clothes washing were intensively manual,29Levine JA Weisell R Chevassus S Martinez CD Burlingame B Coward WA The work burden of women.Science. 2001; 294: 812Crossref PubMed Scopus (52) Google Scholar and walking was required for socialization.30Weber R The transparent village: the community and child rearing in Trinidad and Tobago.Desarro Base. 1994; 18: 19-31PubMed Google Scholar In the short span of 150 years, we have forsaken our legs as a means of locomotion, work, and leisure. We are designed to walk all day long, and Nemoto's article suggests that we should. I would like to acknowledge helpful discussions with Susan Fried, PhD.