Are cardiovascular and metabolic responses to field walking tests interchangeable and obesity-dependent?

Responses of different functional tests in candidates for bariatric surgery and the association with body composition, metabolic and lipid profile

Individuals with obesity can have metabolic disorders and may develop impairments that affect the ability to exercise. The maximal incremental cardiopulmonary exercise test is widely used to assess functional capacity. However, submaximal tests such as the two-minute step test (2MST) and the six-minute walk test (6MWT) also allow this assessment. We propose to analyze whether body composition, metabolic and lipid profile influence the maximal and submaximal performance, and investigate these variables in response to different functional tests. Forty-four individuals with obesity, aged 18–50 years, underwent analysis of body composition, metabolic and lipid profile, incremental treadmill test (ITMT), 6MWT, and 2MST. One-way ANOVA, Pearson or Spearman correlation, and Stepwise multiple linear regression analysis were performed. ITMT induced a greater metabolic, ventilatory, cardiovascular, and perceived exertion demand when compared to the 6MWT and 2MST (p < 0.05). In addition, 2MST elicited a higher chronotropic (HR) and metabolic (V̇O₂) demand when compared to the 6MWT (p < 0.05). Significant correlations were found between tests and body composition, metabolic and lipid profile. Fat mass and low-density lipoprotein can explain 30% of the V̇O₂ variance in the ITMT; and fat mass, glucose, and performance in the 2MST can explain 42% of the variance of the distance walked in the ITMT. Obesity and its metabolic impairments are capable of influencing responses to exercise. ITMT generated greater demand due to the high stress imposed, however, 2MST demanded greater metabolic and chronotropic demand when compared to the 6MWT.

Criterion-Related Validity of Field-Based Fitness Tests in Adults: A Systematic Review

We comprehensively assessed the criterion-related validity of existing field-based fitness tests used to indicate adult health (19–64 years, with no known pathologies). The medical electronic databases MEDLINE (via PubMed) and Web of Science (all databases) were screened for studies published up to July 2020. Each original study’s methodological quality was classified as high, low and very low, according to the number of participants, the description of the study population, statistical analysis and systematic reviews which were appraised via the AMSTAR rating scale. Three evidence levels were constructed (strong, moderate and limited evidence) according to the number of studies and the consistency of the findings. We identified 101 original studies (50 of high quality) and five systematic reviews examining the criterion-related validity of field-based fitness tests in adults. Strong evidence indicated that the 20 m shuttle run, 1.5-mile, 12 min run/walk, YMCA step, 2 km walk and 6 min walk test are valid for estimating cardiorespiratory fitness; the handgrip strength test is valid for assessing hand maximal isometric strength; and the Biering–Sørensen test to evaluate the endurance strength of hip and back muscles; however, the sit-and reach test, and its different versions, and the toe-to-touch test are not valid for assessing hamstring and lower back flexibility. We found moderate evidence supporting that the 20 m square shuttle run test is a valid test for estimating cardiorespiratory fitness. Other field-based fitness tests presented limited evidence, mainly due to few studies. We developed an evidence-based proposal of the most valid field-based fitness tests in healthy adults aged 19–64 years old.

Testes funcionais validados em indivíduos hospitalizados e não hospitalizados: revisão sistemática

Objetivo: Realizar uma revisão sistemática sobre os testes funcionais validados em diferentes perfis de indivíduos hospitalizados e não hospitalizados e avaliar as evidências psicométricas para confiabilidade e validade. Métodos: Trata-se de uma revisão sistemática. Foram utilizadas as bases de dados EMBASE, MEDLINE, Lilacs e SciELO com as palavras-chave Functional Tests (Walk Test, Gait Speed Test, Chair Stand Test, Timed Up And Go, Step Test),Validation Studies as Topic e sinônimos. Foram incluídos estudos de validação de testes funcionais em indivíduos hospitalizados ou não hospitalizados que utilizaram os critérios de validade e/ou confiabilidade e relacionaram os testes a diferentes variáveis. Esses artigos poderiam ser observacionais longitudinais ou de corte transversal ou estudos de validação que utilizaram dados de ensaios clínicos. Foram excluídos os artigos que não apresentaram características importantes da amostra e a descrição do teste. Resultados: A pesquisa resultou em 36.150 artigos, e 89 foram incluídos. Os estudos foram organizados em tabelas com informações como autor, ano; critérios de validação; amostra; teste; variáveis associadas; resultados. A qualidade dos artigos foi avaliada por meio da Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies. Conclusão: Os testes funcionais são válidos e confiáveis para a avaliação de indivíduos hospitalizados e não hospitalizados, estando associados à força muscular, capacidade de caminhar, controle postural, atividades de vida diária, risco de quedas, hospitalização e mortalidade.

Validation of the two-minute step test in obese with comorbibities and morbidly obese patients

Cardiopulmonary fitness assessment is a valuable resource to obtain quantitative indicators of an individual's physical performance. The cardiopulmonary exercise test (CPX), considered the gold standard test for this evaluation, is costly and difficult to be accessed by the general population. In order to make this evaluation more accessible, and to better reflect the performance of daily life activities, alternative tests were proposed. Morbidly obese patients present limitations that impair physical performance assessment and could benefit from a test of shorter duration, provided it is validated. This observational study aimed to validate the two-minute step test (2MST) as a tool to evaluate functional capacity (FC) in obese with comorbidities and morbidly obese patients, compared the 2MST with CPX as a measure of physical performance, and developed a predictive equation to estimate peak oxygen uptake (VO₂) in the 2MST. The CPX and the 2MST were performed and metabolic and ventilatory parameters were recorded in 31 obese individuals (BMI>35 kg/m²). Pearson correlation and multiple linear regression analyses were performed to evaluate the peak VO₂ best predictors. Bland-Altman analysis was performed to assess the agreement between the two methods. Peak VO₂ measured by CPX and 2MST showed a strong correlation (r=0.70, P<0.001) and there was a moderate correlation between peak VO₂ of the 2MST and the number of up-and-down step cycles (UDS) (r=0.55; P=0.01). The reference equation obtained was: VO₂ (mL·kg^-1·min^-1) = 13.341 + 0.138 × total UDS – (0.183 × BMI), with an estimated standard error of 1.3 mL·kg^-1·min^-1. The 2MST is a viable, practical, and easily accessible test for FC. UDS and BMI can predict peak VO₂ satisfactorily.

Evaluation of exercise capacity using two field tests in patients with metabolic syndrome

PURPOSE

Field tests are popular for assessing exercise capacity because they are practical and have established validity. The objective of this study was to compare physiological responses and exercise performance of patients with metabolic syndrome in two field tests of exercise capacity.

MATERIAL AND METHODS

Forty-seven patients diagnosed with metabolic syndrome participated in this cross-sectional study. Exercise capacity was assessed using incremental shuttle walk test and six-minute walk test. Factors determining exercise capacity and agreement between the two tests were also investigated.

RESULTS

Metabolic syndrome patients achieved a significantly greater percentage of predicted maximal heart rate, blood pressure, and longer distance in the incremental shuttle walk test than in the six-minute walk test (p < 0.001). Gender and body mass index explained 48.5% of the variance in six-minute walk test distance (R = 0.697, R² = 0.485, F_(2-46) = 20.737, p < 0.001). Body mass index and fat-free mass explained 55% of the variance in incremental shuttle walk test distance (R = 0.746, R²= 0.557, F_(2-46) = 27.623, p < 0.001).

CONCLUSIONS

Despite the agreement in the percentages of predicted maximal heart rate during these two field tests, the incremental shuttle walk test may be a better assessment tool than the six-minute walk test because it elicits more pronounced and definitive physiological responses to exercise tolerance in patients with metabolic syndrome.IMPLICATIONS FOR REHABILITATIONThe incremental shuttle walk test can be used to evaluate exercise capacity in metabolic syndrome.The incremental shuttle walk test elicits greater physiological responses than the six-minute walk test.The incremental shuttle walk test may be preferable over the six-minute walk test in investigating exercise capacity.Both tests can guide and assist in the evaluation of this patient population in clinical practice.Body mass index affected distance in both exercise tests.

Management of cardiovascular diseases in patients with obesity

The management of cardiovascular diseases (CVD) in patients with obesity presents numerous challenges. Obesity has a negative effect on almost all of the major CVD risk factors, and adversely influences cardiovascular structure and function. Patients who are overweight or obese have a higher incidence of almost all CVDs compared with patients who are of normal weight. However, those who are overweight or obese seem to have a better short-term and medium-term prognosis after major CVD events and interventional procedures or cardiac surgeries than leaner patients, a phenomenon termed the 'obesity paradox'. In considering the mechanisms underlying this paradox, we review evidence of the deleterious consequences of obesity in patients with coronary heart disease, and the limited data on the benefits of weight loss in patients with CVD. Additional studies are needed on the efficacy of purposeful weight loss on cardiovascular outcomes to determine the ideal body composition for patients with CVD.