Submitted on August 18, 2006
Accepted on November 18, 2006
Differences in Glucose Clearance: The Effects of Insulin and Resistance Training on Arm and Leg Glucose Clearance in Older Hypertensive Individuals
Thomas H. Reynolds1*, Mark Supiano2, and Donald R Dengel3
1 Exercise Science, Skidmore College, Saratoga Springs, New York, United States
2 Internal Medicine, University of Utah, United States
3 Kinesiology, University of Minnesota, Minneapolis, Minnesota, United States
* To whom correspondence should be addressed. E-mail: treynold{at}skidmore.edu.
The purpose of this study was to compare the ability of insulin to stimulate glucose uptake in the arm and the leg a group of older hypertensives (n = 13, age=66±2 yr). We also examined the effect of a 4-month whole body resistance training (RT) program on arm and leg glucose clearance during a hyperinsulinemic-euglycemic clamp. During the hyperinsulinemic-euglycemic clamp, GC was assessed by simultaneously measuring arm and leg blood flow (BF) and assessing the fractional glucose extraction (GE) in blood samples obtained from the brachial artery, brachial vein, and popliteal vein. At baseline, a significant main effect (arm vs. leg) was observed demonstrating greater GC and BF in the arm compared to the leg (GC: P=0.006; BF: P=0.012). Insulin significantly increased GE, BF, and GC in both the arm and leg (main effects: GE, P=0.0001; BF, P =0.0001; GC, P=0.0001) at baseline. However, the effect of insulin was similar in the arm and leg. Following RT, a significant main effect (baseline vs. RT) was observed demonstrating greater GE and GC in the leg (GE, P=0.024; GC, P=0.053), but not in the arm (GE, P=0.31; GC, P=0.14). No significant main effect (baseline vs. RT) for BF in either the arm or the leg was observed following RT. In conclusion, the greater glucose clearance in the arm compared to the leg at baseline is primarily due to enhanced arm blood flow. Furthermore, whole body RT appears to increase glucose clearance in the leg but not the arm.
