Reduced leg blood flow during submaximal exercise in type 2 diabetes.
It is unclear whether impaired cardiac and/or vascular function contribute to exercise intolerance in patients with type 2 diabetes.


OBJECTIVE
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.


METHODS
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.


RESULTS
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.


CONCLUSIONS
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.
Lalande
Sophie
S
Department of Sport and Exercise Science, University of Auckland, Auckland, New Zealand. lalande.sophie@mayo.edu
Gusso
Silmara
S
Hofman
Paul L
PL
Baldi
James C
JC
D000328:Adult; D003924:Diabetes Mellitus, Type 2 / Q000150:complications / Q000503:physiopathology*; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test; D017079:Exercise Tolerance / Q000502:physiology*; D005263:Femoral Artery; D006801:Humans; D007866:Leg / Q000098:blood supply*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D010807:Physical Endurance; D010865:Pilot Projects; D012146:Rest / Q000502:physiology; D012307:Risk Factors