Early blood pressure response to isometric exercise is attenuated in obese individuals who have undergone bariatric surgery

Objective Blood pressure (BP) reactivity to stress is predictive of the development of cardiovascular disease. Cardiovascular reactivity is attenuated in individuals after bariatric surgery; however, the underlying mechanisms are not completely understood. We hypothesized the BP response at the onset of isometric handgrip exercise would occur earlier and to a lesser degree in individuals who underwent bariatric surgery when compared to obese adults and the reliance on total peripheral resistance (TPR) would be attenuated. Methods Twenty‐six individuals [7 non‐obese (28±3 yrs, 23±1 kg/m 2 ), 11 obese (33±2 yrs, 39±1 kg/m 2 ), 8 post‐bariatric surgery (35±2 yrs, 29±1 kg/m 2 )] completed isometric handgrip exercise (40% maximum voluntary contraction) to exhaustion. Heart rate (HR, ECG) and arterial BP (brachial catheter) were measured continuously. Stroke volume was estimated from the pressure waveform and cardiac output (CO) and TPR were calculated. Peak change, time to peak, and rate of rise in BP were assessed during the first 30‐s of exercise. Results Compared to non‐obese controls, obese adults exhibited a slower initial rise in BP (9.3± 3.9 vs 21.7±2.5 s) and higher peak BP change (Δ6.7±2.1 vs Δ11.9±2.1 mmHg) at the onset of isometric handgrip exercise (p<0.05). Peak BP and the rate of rise were not different between individuals who underwent bariatric surgery (14.0±4.1 s, Δ5.6±1.3 mmHg) and non‐obese controls (p>0.05). Non‐obese controls exhibited an exercise‐mediated increase in CO whereas obese adults increased TPR (p<0.05). The increases in CO and TPR were less apparent in individuals who underwent bariatric surgery (p>0.05). Low cardiac baroreflex sensitivity (BRS) and heart rate variability (HRV: SDNN, standard deviation of normal to normal R‐R intervals) at rest were related to smaller increases in CO (BRS: R=0.47, p<0.01; SDNN: R=0.57, p<0.01) and greater increases in TPR (BRS: R=−0.49, p=0.01; SDNN: R=−0.60, p<0.01) during exercise. Conclusions In contrast to obese adults, individuals who underwent bariatric surgery exhibit a rapid rise in BP at the onset of isometric handgrip exercise. This rapid increase in BP is associated with a fall in TPR and results in lower peak BP at the onset of isometric exercise. These data suggest bariatric surgery attenuates BP reactivity to physical stress via improvements in the time‐course of hemodynamic responses and reflex autonomic adjustments. Support or Funding Information NIH HL130339, NIH HL083947, NIH DK82424, NIH UL1 RR024150, Mayo Clinic Department of Anesthesiology, Mayo Foundation for Medical Education and Research This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .