Reduced leg blood flow during submaximal exercise in type 2 diabetes

• Published in: Medicine and science in sports and exercise Vol. 40; no. 4; p. 612
• Main Authors: Lalande, Sophie, Gusso, Silmara, Hofman, Paul L, Baldi, James C
• Format: Journal Article
• Language: English
• Published: United States 01.04.2008
• Subjects: Adult; Diabetes Mellitus, Type 2 - complications; Diabetes Mellitus, Type 2 - physiopathology; Exercise - physiology; Exercise Test; Exercise Tolerance - physiology; Femoral Artery; Humans; Leg - blood supply; Magnetic Resonance Imaging; Male; Middle Aged; Physical Endurance; Pilot Projects; Rest - physiology; Risk Factors
• ISSN: 0195-9131
• DOI: 10.1249/MSS.0b013e318161aa99

It is unclear whether impaired cardiac and/or vascular function contribute to exercise intolerance in patients with type 2 diabetes. Magnetic resonance imaging (MRI) was used to determine whether reductions in cardiac output and/or femoral arterial blood flow contribute to reduced aerobic capacity in patients with type 2 diabetes. Cardiac and femoral arterial blood flow MRI scans were performed at rest and during low-intensity leg exercise in eight patients with type 2 diabetes and 11 healthy individuals. Maximal aerobic capacity VO(2 max) and maximal oxygen pulse were also determined in all participants. V O(2 max) was 20% lower and maximal oxygen pulse was 16% lower in patients with type 2 diabetes (P < 0.05), whereas maximal heart rate was the same between groups. Low-intensity exercise induced a 20% increase in heart rate and cardiac output as well as a 60-70% increase in femoral blood flow in both groups (P < 0.05). Femoral arterial blood flow indexed to thigh lean mass was reduced during exercise in patients with type 2 diabetes compared with healthy individuals. Stroke volume indexed to fat-free mass was lower in patients with type 2 diabetes, but greater heart rate allowed cardiac output to be maintained during submaximal exercise. These findings suggest that impaired femoral arterial blood flow, an indirect marker of muscle perfusion, affects low-intensity exercise performance in patients with type 2 diabetes. However, because of lower exercising stroke volume, we propose that femoral arterial blood flow and, possibly, cardiac output, limit V O(2 max) in patients with type 2 diabetes.