Assessing Cardiorespiratory Fitness Without Performing Exercise Testing

Chang

et al. 2016

JAHA

BackgroundThe structure of the aorta is considered to influence exercise systolic blood pressure (SBP) response, which, in turn, might impact upon adverse outcomes. The current study sought to investigate the relationship of aortic calcification and exercise SBP with adverse outcomes among elderly individuals.Methods and ResultsWe retrospectively reviewed 702 elderly individuals (>65 years of age) without obstructive coronary artery disease (CAD; luminal stenosis <50%) who underwent coronary computed tomography (CT) and exercise treadmill testing. ΔSBP stage2 and ΔSBP peak were defined as the difference in systolic blood pressure (SBP) between rest and stage 2 or peak exercise, respectively. Thoracic aortic calcium score (TACS) and coronary artery calcium score (CACS) were measured using CT scanning procedures. The primary endpoints were defined as all‐cause death, admission for heart failure, obstructive CAD requiring coronary intervention, and stroke. In multivariable models, ΔSBP stage2 and ΔSBP peak were positively related with log(TACS+1), even after adjusting for various clinical variables, baseline SBP, and CACS (P<0.001). During a median follow‐up period of 65 months, there were 59 events (8.4%). In a multivariate Cox regression model, independent predictors for all events were age (hazard ratio [HR], 1.12; 95% CI, 1.05–1.19; P<0.001), dyslipidemia (HR, 1.96; 95% CI, 1.14–3.37; P=0.015), and the 4th quartile of TACS (HR, 1.24; 95% CI, 1.03–1.49; P=0.024). Among individual events, the 4th quartile of TACS was the only independent predictor for stroke (HR, 2.15; 95% CI, 1.09–5.13; P=0.044), whereas CACS ≥400 mm3 was an independent predictor for obstructive CAD requiring intervention (HR, 7.04; 95% CI, 1.58–31.36; P=0.010).ConclusionsAortic calcification was related to SBP response during exercise and was an independent predictor for outcomes, especially stroke, regardless of resting SBP or CACS.

Section: Discussionmentioning

confidence: 99%

Association of Thoracic Aorta Calcium Score With Exercise Blood Pressure Response and Clinical Outcomes in Elderly Individuals: Differential Impact of Aorta Calcification Compared With Coronary Artery Calcification

Chang

et al. 2016

JAHA

“…In addition, self-reported exercise habits correlate with physical capacity and can be used to infer fitness with decent accuracy. 14,28,29 The strength of the associations between high fitness and cardiovascular risk markers would be attenuated by overestimation of cardiorespiratory fitness and the resulting misclassification of patients into the moderate or high fitness group when they were actually low or moderate fitness individuals, respectively. Hence, the relationships found here should be considered conservative estimates; the true associations may be even stronger.…”

Section: Discussionmentioning

confidence: 99%

High fitness is associated with a better cardiovascular risk profile in patients with type 2 diabetes mellitus

et al. 2011

Novel cardiovascular risk markers, such as ambulatory blood pressure (BP) and aortic stiffness, have been proposed. The aim of this study was to investigate the relationship between physical fitness and some of these risk markers in 575 type 2 diabetic patients. In a cross-sectional design, clinical, laboratory, echocardiographic, aortic pulse wave velocity and 24-h ambulatory BP monitoring data were obtained. Fitness was self-reported using a standard questionnaire of daily activities, and then assessed as belonging to one of the three categories: low (o4 metabolic equivalents (METs)), moderate (X4 to o7 METs) and high fitness (X7 METs). In a random sub-sample of 265 patients, self-reported fitness was confirmed by a standard treadmill test. Statistical analysis was carried out, using tests including bivariate tests among the three categories and multivariate logistic regression. Agreement between self-reported and measured fitness was substantial (weighted j: 0.63). High fitness patients were younger, frequently male, had a decreased prevalence of degenerative complications, lower office and ambulatory BP levels, particularly during the night and had an increased prevalence of the normal nocturnal dipping pattern. High fitness patients also had lower hemoglobin A1c and C-reactive protein levels, a decreased prevalence of left ventricular hypertrophy and increased aortic stiffness. On multiple logistic regression, after adjustments for several confounders, high fitness was independently associated with a higher likelihood of having low C-reactive protein (odds ratio (OR): 2.3, 95% confidence interval (CI): 1.3-3.9), controlled nighttime BP (OR: 2.3, 95% CI: 1.4-3.8), normal dipping pattern (OR: 2.1, 95% CI: 1.2-3.5) and low aortic stiffness (OR: 2.5, 95% CI: 1.3-4.8). Patients with moderate fitness had intermediate OR. In conclusion, a moderate to high level of physical fitness was independently associated with several favorable intermediate cardiovascular risk markers, which may contribute to decreasing the burden of morbi-mortality in patients with type 2 diabetes. Hypertension Research (2011) 34, 856-861; doi:10.1038/hr.2011; published online 12 May 2011Keywords: ambulatory blood pressure; aortic stiffness; cardiorespiratory fitness; C-reactive protein; type 2 diabetes INTRODUCTION Studies in type 2 diabetic patients have found that high levels of aerobic fitness are associated with lower levels of overall mortality and mortality due to cardiovascular events, independent of traditional cardiovascular risk factors. 1,2 However, the relationship between cardiorespiratory fitness and some recently described non-traditional cardiovascular risk factors, such as ambulatory blood pressures (BPs), aortic stiffness and C-reactive protein, has not been as well characterized for type 2 diabetic patients. Whether these factors contribute independently to low fitness or merely reflect more advanced cardiovascular complications is unknown.Compared with office BPs, ambulatory BPs are stronger cardiovascular risk predictors...

“…(5) Although the derived equation was validated against objectively measured VO 2 max, the instrument has not been validated in an Asian population, which is physiologically different from a Caucasian population. (6) The primary objective of the present study was to crossvalidate the NEFA equation (5) in an Asian population, specifically Singaporean adults. The secondary objective of the study was to cross-validate a modified NEFA equation without HR rest as a variable, in order to accommodate circumstances where measuring HR rest might not be feasible or accurate.…”

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confidence: 99%

“…Before CPX, participants were asked to rest quietly for 5 mins before HR rest was measured using the Polar ® heart rate monitor with participants in the seated position. In accordance with the procedure outlined by Jurca et al, (5) participants were asked to select one of the five levels of self-reported physical activity that best described their usual activity pattern: (a) level 0 -inactive or little activity other than usual daily activities; …”

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confidence: 99%

Cross-validation of a non-exercise measure for cardiorespiratory fitness in Singaporean adults

Sloan¹,

Haaland²,

Leung³

et al. 2013

smedj

Commonly expressed as maximal oxygen consumption (VO 2 max) or maximum metabolic equivalents of task (METs), CRF at the metabolic level quantifies the functional capacity of the body to transport and use oxygen via the respiratory, cardiovascular and skeletal muscle systems. Low CRF level has been identified as an independent predictor for an array of health outcomes, including cardiovascular disease, type 2 diabetes mellitus, cancer, poor mental health, falls and premature death. (2)(3)(4) Although maximal graded exercise testing remains the gold standard for the measurement of CRF, it is often impractical to provide this in allied health, fitness and primary care settings due to a lack of space, equipment, personnel, time and participant cooperation. To overcome these barriers to testing, Jurca et al developed and validated the non-exercise fitness assessment (NEFA) for Caucasian populations in 2005. (5) Derived from a regression equation that used the variables of age, gender, body mass index (BMI), resting heart rate (HR rest ) and self-reported physical activity level, NEFA is able to estimate CRF level. (5) Although the derived equation was validated against objectively measured VO 2 max, the instrument has not been validated in an Asian population, which is physiologically different from a Caucasian population. (6) The primary objective of the present study was to crossvalidate the NEFA equation (5) in an Asian population, specifically Singaporean adults. The secondary objective of the study was to cross-validate a modified NEFA equation without HR rest as a variable, in order to accommodate circumstances where measuring HR rest might not be feasible or accurate. M E TH O DSThe participants (n = 100) comprised Singaporean adults recruited from area community centres and tertiary institutions in Singapore. Recruitment was done via electronic and print media advertisements. The required sample size of the study was calculated to give a power of over 80%. Participants underwent medical screening to determine their sutability for inclusion in the study. Written informed consent was obtained from all eligible participants prior to any testing. All performed procedures were approved by the Institutional Review Board of Republic Polytechnic, Singapore.Apparently healthy (7) men (n = 57) and women (n = 43) aged between 18 and 65 years were recruited for the study.