Cardiac Vagal Index Does Not Explain Age-Independent Maximal Heart Rate

Duarte, Carlos Vieira; Araújo, Claudio Gil

doi:10.1055/s-0032-1323818

Cited by 10 publications

(9 citation statements)

References 17 publications

(19 reference statements)

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“…In addition to the abovementioned primarily methodological studies, several other physiological and clinical studies have been published using 4sET both by our group 29 - 34 and by other groups in Brazil 35 - 37 and abroad 38 - 40 . This study will help consolidate 4sET as a protocol for assessing cardiac vagal modulation by providing reference values for the Brazilian adult population.…”

Section: Discussionmentioning

confidence: 98%

4-Second Exercise Test: Reference Values for Ages 18-81 Years

Araújo¹,

Castro²,

Franca³

et al. 2015

Arquivos Brasileiros De Cardiologia

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BackgroundPhysiological reflexes modulated primarily by the vagus nerve allow the heart to decelerate and accelerate rapidly after a deep inspiration followed by rapid movement of the limbs. This is the physiological and pharmacologically validated basis for the 4-s exercise test (4sET) used to assess the vagal modulation of cardiac chronotropism.ObjectiveTo present reference data for 4sET in healthy adults.MethodsAfter applying strict clinical inclusion/exclusion criteria, 1,605 healthy adults (61% men) aged between 18 and 81 years subjected to 4sET were evaluated between 1994 and 2014. Using 4sET, the cardiac vagal index (CVI) was obtained by calculating the ratio between the duration of two RR intervals in the electrocardiogram: 1) after a 4-s rapid and deep breath and immediately before pedaling and 2) at the end of a rapid and resistance-free 4-s pedaling exercise.ResultsCVI varied inversely with age (r = -0.33, p < 0.01), and the intercepts and slopes of the linear regressions between CVI and age were similar for men and women (p > 0.05). Considering the heteroscedasticity and the asymmetry of the distribution of the CVI values according to age, we chose to express the reference values in percentiles for eight age groups (years): 18–30, 31–40, 41–45, 46–50, 51–55, 56–60, 61–65, and 66+, obtaining progressively lower median CVI values ranging from 1.63 to 1.24.ConclusionThe availability of CVI percentiles for different age groups should promote the clinical use of 4sET, which is a simple and safe procedure for the evaluation of vagal modulation of cardiac chronotropism.

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Section: Discussionmentioning

confidence: 98%

4-Second Exercise Test: Reference Values for Ages 18-81 Years

Araújo¹,

Castro²,

Franca³

et al. 2015

Arquivos Brasileiros De Cardiologia

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“…(kg.min) -1 ] values were predicted by gender-specific equations 10: 60 - 0.55 x age (years) for men and 48 - 0.37 x age (years) for women. Maximum values of HR were age-predicted by a previously validated equation: HR max (bpm) = 208 - 0.7 x age (years) 11.…”

Section: Methodsmentioning

confidence: 99%

Influence of central obesity in estimating maximal oxygen uptake

Silva

Franklin

Araújo

2016

Clinics

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OBJECTIVE:To assess the influence of central obesity on the magnitude of the error of estimate of maximal oxygen uptake in maximal cycling exercise testing.METHOD:A total of 1,715 adults (68% men) between 18-91 years of age underwent cardiopulmonary exercise testing using a progressive protocol to volitional fatigue. Subjects were stratified by central obesity into three quartile ranges: Q1, Q2-3 and Q4. Maximal oxygen uptake [mL.(kg.min)-1] was estimated by the attained maximal workload and body weight using gender- and population-specific equations. The error of estimate [mL.(kg.min)-1] and percent error between measured and estimated maximal oxygen uptake values were compared among obesity quartile ranges.RESULTS:The error of estimate and percent error differed (mean ± SD) for men (Q1=1.3±3.7 and 2.0±10.4; Q2-3=0.5±3.1 and -0.5±13.0; and Q4=-0.3±2.8 and -4.5±15.8 (p<0.05)) and for women (Q1=1.6±3.3 and 3.6±10.2; Q2-3=0.4±2.7 and -0.4±11.8; and Q4=-0.9±2.3 and -10.0±22.7 (p<0.05)).CONCLUSION:Central obesity directly influences the magnitude of the error of estimate of maximal oxygen uptake and should be considered when direct expired gas analysis is unavailable.

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“…The predicted values of maximum HR were obtained from the equation 208 - 0.7 x age 22 , for patients of both sexes.…”

Section: Methodsmentioning

confidence: 99%

Sex-Specific Equations to Estimate Maximum Oxygen Uptake in Cycle Ergometry

Silva¹,

Araújo²

2015

Arquivos Brasileiros De Cardiologia

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BackgroundAerobic fitness, assessed by measuring VO2max in maximum cardiopulmonary exercise testing (CPX) or by estimating VO2max through the use of equations in exercise testing, is a predictor of mortality. However, the error resulting from this estimate in a given individual can be high, affecting clinical decisions.ObjectiveTo determine the error of estimate of VO2max in cycle ergometry in a population attending clinical exercise testing laboratories, and to propose sex-specific equations to minimize that error.MethodsThis study assessed 1715 adults (18 to 91 years, 68% men) undertaking maximum CPX in a lower limbs cycle ergometer (LLCE) with ramp protocol. The percentage error (E%) between measured VO2max and that estimated from the modified ACSM equation (Lang et al. MSSE, 1992) was calculated. Then, estimation equations were developed: 1) for all the population tested (C-GENERAL); and 2) separately by sex (C-MEN and C-WOMEN).ResultsMeasured VO2max was higher in men than in WOMEN: -29.4 ± 10.5 and 24.2 ± 9.2 mL.(kg.min)-1 (p < 0.01). The equations for estimating VO2max [in mL.(kg.min)-1] were: C-GENERAL = [final workload (W)/body weight (kg)] x 10.483 + 7; C-MEN = [final workload (W)/body weight (kg)] x 10.791 + 7; and C-WOMEN = [final workload (W)/body weight (kg)] x 9.820 + 7. The E% for MEN was: -3.4 ± 13.4% (modified ACSM); 1.2 ± 13.2% (C-GENERAL); and -0.9 ± 13.4% (C-MEN) (p < 0.01). For WOMEN: -14.7 ± 17.4% (modified ACSM); -6.3 ± 16.5% (C-GENERAL); and -1.7 ± 16.2% (C-WOMEN) (p < 0.01).ConclusionThe error of estimate of VO2max by use of sex-specific equations was reduced, but not eliminated, in exercise tests on LLCE.

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Cardiac Vagal Index Does Not Explain Age-Independent Maximal Heart Rate

Cited by 10 publications

References 17 publications

4-Second Exercise Test: Reference Values for Ages 18-81 Years

4-Second Exercise Test: Reference Values for Ages 18-81 Years

Influence of central obesity in estimating maximal oxygen uptake

Sex-Specific Equations to Estimate Maximum Oxygen Uptake in Cycle Ergometry

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