Cardiovascular and cerebral hemodynamics during exercise and recovery in obese individuals as a function of their fitness status

The aim of this study was to compare cardiovascular hemodynamics and cerebral oxygenation/perfusion (COP) during and after maximal incremental exercise in obese individuals according to their aerobic fitness versus age-matched healthy controls (AMHC). Fifty-four middle-aged obese (OB) and 16 AMHC were recruited. Maximal cardiopulmonary function (gas exchange analysis), cardiac hemodynamics (impedance cardiography), and left frontal COP (near-infrared spectroscopy: NIRS) were measured continuously during a maximal incremental ergocycle test. During recovery, reoxygenation/perfusion rate (ROPR: oxyhemoglobin: ΔO2Hb, deoxyhemoglobin: ΔHHb and total hemoglobin: ΔtHb; with NIRS) was also measured. Obese participants (OB, n = 54) were divided into two groups according to the median V˙O2 peak: the low-fit obese (LF-OB, n = 27) and the high-fit obese (HF-OB, n = 27). During exercise, end tidal pressure of CO2 (PETCO2), and COP (ΔO2Hb, ΔHHb and ΔtHb) did not differ between groups (OB, LF-OB, HF-OB, AMHC). During recovery, PETCO2 and ROPR (ΔO2Hb, ΔHHb and ΔtHb) were similar between the groups (OB, LF-OB, HF-OB, AMHC). During exercise and recovery, cardiac index was lower (P < 0.05) in LF-OB versus the other two groups (HF-OB, AMHC). As well, systolic blood pressure was higher during exercise in the OB, LF-OB and HF-OB groups versus AMHC (P < 0.05). When compared to AMHC, obese individuals (OB, LF-OB, HF-OB) have a similar cerebral vasoreactivity by CO2 and cerebral hemodynamics during exercise and recovery, but a higher systolic blood pressure during exercise. Higher fitness in obese subjects (HF-OB) seems to preserve their cardiopulmonary and cardiac function during exercise and recovery.