Impaired exercise-induced blood volume in type 2 diabetes with or without peripheral arterial disease measured by continuous-wave near-infrared spectroscopy.
OBJECTIVE
Diabetes is a significant risk factor for peripheral arterial disease (PAD) and is associated with accelerated atherosclerosis and limb loss. However, the pathophysiology involved in PAD is unclear. This study was conducted to evaluate the hemodynamic response to exercise of patients with and without diabetes and PAD.


METHODS
The hemodynamic response in calf muscles of patients with diabetes, PAD, or both was determined using near-infrared spectroscopy (NIRS). Patients performed both a plantar-flexion and treadmill-walking exercise regimen.


RESULTS
Skeletal muscle capillary blood volume expansion during exercise, as measured by NIRS, was significantly impaired in the lower extremities of diabetic patients with a normal ankle-brachial index. The relative deoxygenation and oxygenation recovery times measured by NIRS correlates significantly with the presence of PAD.


CONCLUSIONS
Patients with diabetes have reduced capillary volume expansion even without PAD. This is likely due to impaired vasodilation secondary to endothelial dysfunction. Further studies are needed to determine whether pharmaceutical intervention improves the blood volume expansion in the diabetic state.
Mohler
Emile R
ER
Cardiovascular Division, Vascular Medicine Section, Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia, 19104, USA. mohlere@uphs.upenn.edu
Lech
Gwen
G
Supple
Gregory E
GE
Wang
Hao
H
Chance
Britton
B
D000368:Aged; D001810:Blood Volume; D003924:Diabetes Mellitus, Type 2 / Q000378:metabolism / Q000503:physiopathology*; D015444:Exercise; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000378:metabolism; D016491:Peripheral Vascular Diseases / Q000378:metabolism / Q000503:physiopathology*; D019265:Spectroscopy, Near-Infrared
D010100:Oxygen