Muscle blood flow responses to dynamic exercise in young obese humans.
Exercise is a common nonpharmacological way to combat obesity; however, no studies have systematically tested whether obese humans exhibit reduced skeletal muscle blood flow during dynamic exercise. We hypothesized that exercise-induced blood flow to skeletal muscle would be lower in young healthy obese subjects (body mass index of >30 kg/m(2)) compared with lean subjects (body mass index of <25 kg/m(2)). We measured blood flow (Doppler Ultrasound of the brachial and femoral arteries), blood pressure (auscultation, Finapress), and heart rate (ECG) during rest and two forms of single-limb, steady-state dynamic exercise: forearm exercise (20 contractions/min at 4, 8, and 12 kg) and leg exercise (40 kicks/min at 7 and 14 W). Forearm exercise increased forearm blood flow (FBF) similarly in both groups (P > 0.05; obese subjects n = 9, lean subjects n = 9). When FBF was normalized for perfusion pressure, forearm vascular conductance was not different between groups at increasing workloads (P > 0.05). Leg exercise increased leg blood flow (LBF) similarly in both groups (P > 0.05; obese subjects n = 10, lean subjects n = 12). When LBF was normalized for perfusion pressure, leg vascular conductance was not different between groups at increasing workloads (P > 0.05). These results were confirmed when relative blood flow was expressed at average relative workloads. In conclusion, our results show that obese subjects exhibited preserved FBF and LBF during dynamic exercise.
Limberg
Jacqueline K
JK
Dept. of Kinesiology, School of Education, Univ. of Wisconsin, Madison, WI 53706, USA.
De Vita
Michael D
MD
Blain
Gregory M
GM
Schrage
William G
WG
D000328:Adult; D000886:Anthropometry; D001132:Arm / Q000098:blood supply / Q000502:physiology; D001794:Blood Pressure / Q000502:physiology; D015992:Body Mass Index; D003627:Data Interpretation, Statistical; D004562:Electrocardiography; D015444:Exercise / Q000502:physiology*; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D007866:Leg / Q000098:blood supply / Q000502:physiology; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000503:physiopathology*; D009765:Obesity / Q000503:physiopathology*; D012039:Regional Blood Flow / Q000502:physiology; D013848:Thigh / Q000098:blood supply; D014655:Vascular Resistance / Q000502:physiology; D055815:Young Adult