Abstract P267: Hemoglobin and Hematocrit Levels are Determinant for Exercise Tolerance in Patients with Class I to III Obesity
Introduction: Considerable proportion of patients with obesity presents exercise intolerance (EI) and are not able to reach maximum values of heart rate (HR) and gas exchange. This has been mainly attributed to the severity of obesity. Hypothesis: We tested the hypothesis that hematologic variables are crucial for EI in these patients, regardless of body mass index (BMI). Objective: To evaluate the associations between haematological variables and EI and cardiorespiratory fitness (CRF) in patients with classes I to III obesity. Methods: We retrospectively evaluated 103 patients with obesity (50 men, 39 ± 5 kg/m2) who underwent cardiopulmonary exercise test on a treadmill in a ramp protocol. The physiological responses were continuously monitored during the test using a gas analyzer. Oxygen uptake (V’O2), CO2 production, minute ventilation, and HR were measured. The EI was considered in the case of peak V’O2 < 83% of predicted value. Red blood cells (RBC), hemoglobin concentration (Hb), hematocrit (Ht), mean corpuscular Hb, white blood cells and platelets were evaluated. Cardiovascular risk (CVR) factors were recorded and patients were divided according to the number of factors existing (low CVR, ≤ 2; moderate CVR, > 2). The associations between variables were investigated, and linear and logistic multivariate analysis, adjusted by age, sex, BMI and CVR, were developed to evaluate the hematological determinants of EI and CRF. Results: Eighteen patients (17.5%) presented EI. These patients had significantly worse values for BMI (41 ± 5 vs. 38 ± 5 kg/m2), RBC (4.3 ± 0.3 vs. 4.9 ± 0.4 .106/mm3), Hb (12.7 ± 0 , 5 vs. 14.7 ± 2.3 g/dL) and Ht (37.3 ± 1.7 vs. 43.8 ± 2.4%). About 25% of patients had Hb values suggestive of anemia. After multivariate logistic regression analysis, BMI (odds ratio, 1.170: 95% confidence interval, 1.009 to 1.358) and Hb (0.439: 0.244 to 0.791) were selected as significant predictors of EI. There was a significant correlation between RBC and maximum HR in bpm (r = 0.44). The Ht was significantly correlated with maximum HR in bpm (r = 0.62) and in % of predicted (r = 0.92) and with peak V’O2 (r = 0.43). After multivariate linear regressions, age and Ht were determinants of maximal HR in bpm (R2 = 0.786). Only the Ht was selected as a determinant of maximal HR in % of predicted (R2 = 0.850). Sex and the Hb were the main determinants of peak V’O2 (R2 = 0.740). Conclusion: hematological parameters such as Hb and Ht play an important role on exercise tolerance and CRF of patients with obesity, independent of the BMI.
Author Disclosures: A.C. Matheus: None. A.R.T. Gagliardi: None. A.E. Oliveira: None. E.F. Sperandio: None. M.B. Nascimento: None. M. Barboza: None. R.P. Silva: None. V.T. Lauria: None. M. Romiti: None. R.L. Arantes: None. V.Z. Dourado: None.
- © 2015 by American Heart Association, Inc.