Fitness Equals Longer Life Expectancy Regardless of Adiposity Levels
2019; Elsevier BV; Volume: 94; Issue: 6 Linguagem: Inglês
10.1016/j.mayocp.2019.04.016
ISSN1942-5546
AutoresJari A. Laukkanen, Setor K. Kunutsor,
Tópico(s)Cardiovascular Function and Risk Factors
ResumoCardiorespiratory fitness (CRF), an index of habitual physical activity (PA), integrates human body function under demanding physiologic states and reflects an individual's functional capacity.1Laukkanen J.A. Kujala U.M. Low cardiorespiratory fitness is a risk factor for death: exercise intervention may lower mortality?.J Am Coll Cardiol. 2018; 72: 2293-2296Crossref Scopus (18) Google Scholar Substantial literature attests to the fact that objective indices of physical performance (eg, hand grip strength, walking speed, and others) both evaluate physical capability and reflect health status.2Cooper R. Kuh D. Hardy R. Mortality Review GroupFALCon and HALCyon Study TeamsObjectively measured physical capability levels and mortality: systematic review and meta-analysis.BMJ. 2010; 341: c4467Crossref PubMed Scopus (759) Google Scholar Indeed, poor physical fitness (comprising low CRF and muscle strength) and obesity are the major hallmarks of an unhealthy lifestyle and may worsen morbidity and mortality. Body mass index (BMI [calculated as weight in kilograms divided by height in meters squared]) and CRF share an inverse relationship in determining obesity3Myers J. Prakash M. Froelicher V. Do D. Partington S. Atwood J.E. Exercise capacity and mortality among men referred for exercise testing.N Engl J Med. 2002; 346: 793-801Crossref PubMed Scopus (2857) Google Scholar and are each associated with cardiovascular disease (CVD) risk. Although conventional CVD risk prediction models, such as Framingham or Systematic Coronary Risk Evaluation, do not consider BMI in their equations,4Conroy R.M. Pyorala K. Fitzgerald A.P. et al.Estimation of ten-year risk of fatal cardiovascular disease in Europe: the SCORE project.Eur Heart J. 2003; 24: 987-1003Crossref PubMed Scopus (4038) Google Scholar, 5D'Agostino Sr., R.B. Grundy S. Sullivan L.M. Wilson P. CHD Risk Prediction GroupValidation of the Framingham coronary heart disease prediction scores: results of a multiple ethnic groups investigation.JAMA. 2001; 286: 180-187Crossref PubMed Scopus (1697) Google Scholar BMI may prove superior to serum cholesterol level in predicting CVD risk.6Faeh D. Braun J. Bopp M. Body mass index vs cholesterol in cardiovascular disease risk prediction models.Arch Intern Med. 2012; 172: 1766-1768Crossref Scopus (15) Google Scholar Almost 3 decades after the first discussion on "fitness vs fatness," Lavie et al7Pandey A. Patel K.V. Lavie C.J. Obesity, central adiposity, and fitness: understanding the obesity paradox in the context of other cardiometabolic parameters.Mayo Clin Proc. 2018; 93: 676-678Abstract Full Text Full Text PDF Scopus (21) Google Scholar, 8Lavie C.J. Cahalin L.P. Chase P. et al.Impact of cardiorespiratory fitness on the obesity paradox in patients with heart failure.Mayo Clin Proc. 2013; 88: 251-258Abstract Full Text Full Text PDF PubMed Scopus (172) Google Scholar suggested that CRF may be as important as BMI in CVD risk assessment. Some other researchers have suggested that the finding of poor clinical outcomes in those with low body fat percentage (BF%) and low BMI may reflect a "lean paradox" of even greater significance than the obesity paradox. The importance and use of CRF in CVD risk stratification have been disregarded, despite consistent evidence that CRF accurately predicts the risk of CVD.9Lavie C.J. De Schutter A. Patel D. Artham S.M. Milani R.V. Body composition and coronary heart disease mortality: an obesity or a lean paradox?.Mayo Clin Proc. 2011; 86: 857-864Abstract Full Text Full Text PDF PubMed Scopus (123) Google Scholar Enhanced CRF may offset the harmful consequences of excess body fatness and other CVD risk factors, thereby enabling individuals to be "fat but fit." Higher levels of CRF are accompanied by a lower risk of CVD outcomes, regardless of levels of BMI.10Barry V.W. Caputo J.L. Kang M. The joint association of fitness and fatness on cardiovascular disease mortality: a meta-analysis.Prog Cardiovasc Dis. 2018; 61: 136-141Crossref Scopus (58) Google Scholar Several reports have also observed that the association of obesity with adverse outcomes is reduced when factored for CRF levels.11Kokkinos P. Faselis C. Franklin B. et al.Cardiorespiratory fitness, body mass index and heart failure incidence.Eur J Heart Fail. 2019; 21: 436-444Crossref Scopus (46) Google Scholar These observations suggest that the association between obesity and increased CVD risk may reflect low CRF and that adverse consequences of obesity on CVD may be offset by improved levels of CRF.12Kunutsor S.K. Laukkanen J.A. Heart failure risk reduction: is fit and overweight or obese better than unfit and normal weight?.Eur J Heart Fail. 2019; 21: 445-448Crossref Scopus (5) Google Scholar Despite the minefield of evidence on the relationships among physical fitness, obesity, and adverse health outcomes, this interplay is still not well understood and is still debated. In the current issue of the journal, Zaccardi et al13Zaccardi F. Davies M.J. Khunti K. Yates T. Comparative relevance of physical fitness and adiposity on life expectancy: a UK Biobank observational study.Mayo Clin Proc. 2019; 94: 985-994Abstract Full Text Full Text PDF PubMed Scopus (27) Google Scholar reported new evidence on the extent to which 2 physical fitness–related measures (walking pace and handgrip strength) are associated with life expectancy across different levels of obesity, as measured by BMI and other adiposity indices, such as waist circumference (WC) and BF%. The rationale for conducting this study is based on limitations of previous studies as pointed out by Zaccardi et al,13Zaccardi F. Davies M.J. Khunti K. Yates T. Comparative relevance of physical fitness and adiposity on life expectancy: a UK Biobank observational study.Mayo Clin Proc. 2019; 94: 985-994Abstract Full Text Full Text PDF PubMed Scopus (27) Google Scholar including (1) not investigating the associations across different BMI levels, (2) failing to explore interactions between CRF and BMI, and (3) reporting hazard ratios that describe associations, which lack a relationship with survival probabilities and make it difficult to interpret direct comparison between the importance of one factor with another. Given that the absolute risk of adverse outcomes depends largely on age, using a single relative metric does not allow quantification of absolute risk differences across increasing ages. The authors suggested that a better approach to evaluate the interplay was to estimate residual life expectancy across CRF levels and BMI. Using the large UK Biobank cohort based on 474,919 participants, the authors13Zaccardi F. Davies M.J. Khunti K. Yates T. Comparative relevance of physical fitness and adiposity on life expectancy: a UK Biobank observational study.Mayo Clin Proc. 2019; 94: 985-994Abstract Full Text Full Text PDF PubMed Scopus (27) Google Scholar demonstrate that participants with a brisk walking pace have a longer and similar life expectancy across the spectrum of BMI or other adiposity indices, providing further evidence that walking pace is an easily available marker of overall health status. They found that coexistence of a low BMI and a slow walking pace was associated with the lowest life expectancy. We applaud this new study, which is clinically valuable and used robust study methods in addition to the large sample size. The authors initially plotted the shapes of the associations of walking pace, handgrip strength, BMI, WC, and BF% with all-cause mortality. In addition to using conventional Cox hazards regression models, the authors conducted analyses of life expectancy and residual life time based on BMI, waking pace, and grip strength. Mortality rates were modeled using Poisson regression methods. Several sensitivity analyses were also performed to confirm the robustness of the results. Their findings showed that participants with brisk walking pace had a longer life expectancy across all categories of BMI compared with slow walkers; women and men reporting a brisk walking pace had a life expectancy of more than 86 and 85 years, respectively. Women and men with low BMI and slow walking pace had the lowest life expectancy, estimated to be 72 and 65 years, respectively. Participants with a slow walking pace had shorter life expectancy across all categories of BMI. The difference in life expectancy between brisk and slow walkers at BMI levels of less than 20 was substantial: 15 and more than 21 years for women and men, respectively. Absolute differences in life expectancy were minor between average and brisk walking pace in women, but they were clearly seen in men with low (<20) BMI, with approximately 5 years' difference between individuals with a brisk vs average walking pace. The same pattern of results was observed for WC and BF%. These findings support the concept that brisk walking speed, which was easily measured by a single-item self-reported questionnaire (slow, average, or brisk pace), and muscle strength are key components that should be maintained by regular physical exercise. The recent study is well in line with the previous concept by Lavie et al7Pandey A. Patel K.V. Lavie C.J. Obesity, central adiposity, and fitness: understanding the obesity paradox in the context of other cardiometabolic parameters.Mayo Clin Proc. 2018; 93: 676-678Abstract Full Text Full Text PDF Scopus (21) Google Scholar, 8Lavie C.J. Cahalin L.P. Chase P. et al.Impact of cardiorespiratory fitness on the obesity paradox in patients with heart failure.Mayo Clin Proc. 2013; 88: 251-258Abstract Full Text Full Text PDF PubMed Scopus (172) Google Scholar indicating that higher levels of CRF may be at least as important as lower BMI in the prevention of CVDs. There were some limitations of the present study that the authors did not acknowledge, including (1) lack of data on PA patterns during follow-up and (2) that the assessment of walking pace was based on self-reports, which may be prone to recall or misclassification bias. The present findings of Zaccardi et al13Zaccardi F. Davies M.J. Khunti K. Yates T. Comparative relevance of physical fitness and adiposity on life expectancy: a UK Biobank observational study.Mayo Clin Proc. 2019; 94: 985-994Abstract Full Text Full Text PDF PubMed Scopus (27) Google Scholar are very important because they shed more light on the interrelationships among fitness levels, adiposity, and life expectancy. People with good CRF have prolonged life expectancy across all levels of adiposity. In addition, they have shown that self-reported walking pace more accurately predicts life expectancy than objectively assessed handgrip strength. A slow walking pace and low BMI are each markers of frailty14Yates T. Zaccardi F. Dhalwani N.N. et al.Association of walking pace and handgrip strength with all-cause, cardiovascular, and cancer mortality: a UK Biobank observational study.Eur Heart J. 2017; 38: 3232-3240Crossref Scopus (120) Google Scholar, 15Iannuzzi-Sucich M. Prestwood K.M. Kenny A.M. Prevalence of sarcopenia and predictors of skeletal muscle mass in healthy, older men and women.J Gerontol A Biol Sci Med Sci. 2002; 57: M772-M777Crossref PubMed Scopus (640) Google Scholar; hence, it is possible that the interplay among slow walking pace, low BMI, and short life expectancy indicates pronounced frailty, poor nutritional status, body weakness, and loss of muscle mass, as postulated by the authors.13Zaccardi F. Davies M.J. Khunti K. Yates T. Comparative relevance of physical fitness and adiposity on life expectancy: a UK Biobank observational study.Mayo Clin Proc. 2019; 94: 985-994Abstract Full Text Full Text PDF PubMed Scopus (27) Google Scholar Frailty reflects impaired functional capacity across multiple organ systems and is often attended by fatigability, diminished muscle strength, and an enhanced predisposition to chronic disease. Previous studies of the associations between indices of functional capacity and adverse outcomes such as CVD and mortality have not been entirely consistent. For example, muscle strength is associated with a salutary effect on CVD independent of the level of CRF. A meta-analysis revealed that indices of muscle strength associate inversely with all-cause mortality in populations residing in the community.2Cooper R. Kuh D. Hardy R. Mortality Review GroupFALCon and HALCyon Study TeamsObjectively measured physical capability levels and mortality: systematic review and meta-analysis.BMJ. 2010; 341: c4467Crossref PubMed Scopus (759) Google Scholar In younger men, a diminished grip strength predisposes to incident coronary heart disease,16Silventoinen K. Magnusson P.K. Tynelius P. Batty G.D. Rasmussen F. Association of body size and muscle strength with incidence of coronary heart disease and cerebrovascular diseases: a population-based cohort study of one million Swedish men.Int J Epidemiol. 2009; 38: 110-118Crossref PubMed Scopus (154) Google Scholar and enhanced isometric muscle strength is attended by less risk of mortality from CVD.17Timpka S. Petersson I.F. Zhou C. Englund M. Muscle strength in adolescent men and risk of cardiovascular disease events and mortality in middle age: a prospective cohort study.BMC Med. 2014; 12: 62Crossref PubMed Scopus (72) Google Scholar Handgrip strength and chair-rise test performance, individually, are associated with the risk of all-cause and CVD mortality, irrespective of the frequency of physical exercise.18Karlsen T. Nauman J. Dalen H. Langhammer A. Wisloff U. The combined association of skeletal muscle strength and physical activity on mortality in older women: the HUNT2 Study.Mayo Clin Proc. 2017; 92: 710-718Abstract Full Text Full Text PDF Scopus (19) Google Scholar This prospective analysis of seemingly healthy older women indicated that 2 readily applied tests of arm strength (handgrip strength) and leg strength (chair-rise test) served as valid predictors of all-cause mortality, CVD, and stroke.18Karlsen T. Nauman J. Dalen H. Langhammer A. Wisloff U. The combined association of skeletal muscle strength and physical activity on mortality in older women: the HUNT2 Study.Mayo Clin Proc. 2017; 92: 710-718Abstract Full Text Full Text PDF Scopus (19) Google Scholar Several other studies, including the UK Biobank, have, however, reported positive associations between grip strength and adverse health outcomes.14Yates T. Zaccardi F. Dhalwani N.N. et al.Association of walking pace and handgrip strength with all-cause, cardiovascular, and cancer mortality: a UK Biobank observational study.Eur Heart J. 2017; 38: 3232-3240Crossref Scopus (120) Google Scholar, 19Leong D.P. Teo K.K. Rangarajan S. et al.Prognostic value of grip strength: findings from the Prospective Urban Rural Epidemiology (PURE) study.Lancet. 2015; 386: 266-273Abstract Full Text Full Text PDF PubMed Scopus (983) Google Scholar Indeed, further research is needed to evaluate the associations between changes in functional capacity with age and CVD outcomes and mortality. Age has a powerful adverse effect on disease outcomes, and a decline in physical capability with age may more accurately predict mortality than the level of physical capability itself at a specific time point. Muscle mass diminishes with age, and this is a major determinant of the well-documented age-dependent diminution in muscle strength. Overall, the UK Biobank findings are of particular significance because the favorable effect of brisk walking pace on life expectancy was evident for the whole population, regardless of BMI category. It is known, in general, that strenuous PA or high-volume or high-intensity exercise is not well-tolerated by obese individuals; however, walking is an attractive and feasible alternative for this population. The findings also add to the plentiful evidence on the health benefits of PA. Indeed, this is no longer a disputed issue, but most populations do not achieve weekly levels recommended by established guidelines: 150 to 300 minutes of moderate-intensity or 75 to 150 minutes of vigorous-intensity aerobic PA/exercise for adults.20Piercy K.L. Troiano R.P. Ballard R.M. et al.The Physical Activity Guidelines for Americans.JAMA. 2018; 320: 2020-2028Crossref PubMed Scopus (2205) Google Scholar To echo Zaccardi et al,13Zaccardi F. Davies M.J. Khunti K. Yates T. Comparative relevance of physical fitness and adiposity on life expectancy: a UK Biobank observational study.Mayo Clin Proc. 2019; 94: 985-994Abstract Full Text Full Text PDF PubMed Scopus (27) Google Scholar further research is needed to examine the phenotypic characteristics of individuals with low BMI and slow walking pace and the effectiveness of targeted strategies to increase CRF and physical function in low-BMI groups. Comparative Relevance of Physical Fitness and Adiposity on Life Expectancy: A UK Biobank Observational StudyMayo Clinic ProceedingsVol. 94Issue 6PreviewTo investigate the extent to which 2 measures of physical fitness—walking pace and handgrip strength—are associated with life expectancy across different levels of adiposity, as the relative importance of physical fitness and adiposity on health outcomes is still debated. Full-Text PDF
Referência(s)