title: Seven days of aerobic exercise training improves conduit artery blood flow following glucose ingestion in patients with type 2 diabetes.
abstract: The vasodilatory effects of insulin account for up to 40% of insulin-mediated glucose disposal; however, insulin-stimulated vasodilation is impaired in individuals with type 2 diabetes, limiting perfusion and delivery of glucose and insulin to target tissues. To determine whether exercise training improves conduit artery blood flow following glucose ingestion, a stimulus for increasing circulating insulin, we assessed femoral blood flow (FBF; Doppler ultrasound) during an oral glucose tolerance test (OGTT; 75 g glucose) in 11 overweight or obese (body mass index, 34 ± 1 kg/m²), sedentary (peak oxygen consumption, 23 ± 1 ml·kg⁻¹·min⁻¹) individuals (53 ± 2 yr) with non-insulin-dependent type 2 diabetes (HbA1c, 6.63 ± 0.18%) before and after 7 days of supervised treadmill and cycling exercise (60 min/day, 60-75% heart rate reserve). Fasting glucose, insulin, and FBF were not significantly different after 7 days of exercise, nor were glucose or insulin responses to the OGTT. However, estimates of whole body insulin sensitivity (Matsuda insulin sensitivity index) increased (P < 0.05). Before exercise training, FBF did not change significantly during the OGTT (1 ± 7, -7 ± 5, 0 ± 6, and 0 ± 5% of fasting FBF at 75, 90, 105, and 120 min, respectively). In contrast, after exercise training, FBF increased by 33 ± 9, 39 ± 14, 34 ± 7, and 48 ± 18% above fasting levels at 75, 90, 105, and 120 min, respectively (P < 0.05 vs. corresponding preexercise time points). Additionally, postprandial glucose responses to a standardized breakfast meal consumed under "free-living" conditions decreased during the final 3 days of exercise (P < 0.05). In conclusion, 7 days of aerobic exercise training improves conduit artery blood flow during an OGTT in individuals with type 2 diabetes.
authors: Dept. of Nutrition and Exercise Physiology, Univ. of Missouri, Columbia, MO 65211, USA.
authors: Catherine R
authors: CR
authors: Mikus
authors: Seth T
authors: ST
authors: Fairfax
authors: Jessica L
authors: JL
authors: Libla
authors: Leryn J
authors: LJ
authors: Boyle
authors: Lauro C
authors: LC
authors: Vianna
authors: Douglas J
authors: DJ
authors: Oberlin
authors: Grace M
authors: GM
authors: Uptergrove
authors: Shekhar H
authors: SH
authors: Deo
authors: Areum
authors: A
authors: Kim
authors: Jill A
authors: JA
authors: Kanaley
authors: Paul J
authors: PJ
authors: Fadel
authors: John P
authors: JP
authors: Thyfault
mesh_terms: D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000097:blood; D001783:Blood Flow Velocity; D001786:Blood Glucose / Q000378:metabolism; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000628:therapy*; D005080:Exercise Test; D005081:Exercise Therapy; D005260:Female; D005263:Femoral Artery / Q000000981:diagnostic imaging / Q000503:physiopathology*; D005947:Glucose / Q000008:administration & dosage* / Q000378:metabolism; D005951:Glucose Tolerance Test; D006442:Glycated Hemoglobin / Q000378:metabolism; D006439:Hemodynamics; D006801:Humans; D007328:Insulin / Q000097:blood; D008297:Male; D008875:Middle Aged; D008923:Missouri; D009765:Obesity / Q000097:blood / Q000503:physiopathology; D010101:Oxygen Consumption; D019518:Postprandial Period; D020127:Recovery of Function; D012039:Regional Blood Flow; D057185:Sedentary Behavior; D013997:Time Factors; D016896:Treatment Outcome; D018616:Ultrasonography, Doppler, Duplex; D014664:Vasodilation
chemical_list: D015415:Biomarkers; D001786:Blood Glucose; D005947:Glucose; D006442:Glycated Hemoglobin; D007328:Insulin; C517652:hemoglobin A1c protein, human