Although intense endurance and resistance exercise training and whey protein supplementation have both been shown to independently improve glycemic control, no known studies have examined the effect of high-intensity mixed-mode interval training (MMIT) and whey supplementation in adults with Type 2 diabetes (T2D).
This study aimed to determine if peritraining whey protein supplementation combined with MMIT can improve glycemic control.
In a double-blind, randomized, placebo-controlled trial, 24 men (55.7 ± 5.6 yr) with T2D performed MMIT with whey (20 g) or placebo control for 10 wk. Glycemic control was assessed via glucose disposal rate during a euglycemic insulin clamp, fasting blood glucose concentration, and homeostatic model assessment of insulin resistance. Changes in peak oxygen consumption, 1-repetition maximum strength, vastus lateralis muscle, and subcutaneous adipose thicknesses, and waist circumference were also assessed.
Ten weeks of MMIT substantially improved glucose disposal rate by 27.5% (90% confidence interval, 1.2%–60.7%) and 24.8% (−5.4% to 64.8%) in the whey and control groups, respectively. There were likely and possible reductions in fasting blood glucose by −17.4% (−30.6% to −1.6%) and homeostatic model assessment of insulin resistance by −14.1% (−25.3% to 1.08%) in the whey group; however, whey effects were not clearly beneficial to glycemic outcomes relative to the control. MMIT also clearly substantially improved 1-repetition maximum by 20.6% (16.3%–24.9%) and 22.7% (18.4%–27.2%), peak oxygen consumption by 22.6% (12.0%–26.2%) and 18.5% (10.5%–27.4%), and vastus lateralis muscle thickness by 18.9% (12.0%–26.2%) and 18.6% (10.5%–27.4%) and possibly reduced waist circumference by −2.1% (−3.1% to −1.0%) and −1.9% (−3.7% to −0.1%) in the control and whey groups, respectively, but the whey–control outcome was trivial or unclear.
A clinically meaningful enhancement in glycemic control after 10 wk of MMIT was not clearly advanced with peritraining whey protein supplementation in middle-age men with T2D.
1School of Sport, Exercise, and Nutrition, Massey University Wellington, Wellington, NEW ZEALAND; 2Department of Exercise and Sport Science, University of North Carolina at Chapel Hill, Chapel Hill, NC; 3Department of Sport and Exercise, University of Winchester, Winchester, UNITED KINGDOM; 4Centre for Endocrine, Diabetes and Obesity Research, Wellington Regional Hospital, Wellington, NEW ZEALAND; and 5Department of Medicine, University of Otago, Wellington, Wellington, NEW ZEALAND
Address for correspondence: David S. Rowlands, Ph.D., School of Sport, Exercise, and Nutrition, Massey University Wellington, 63 Wallace St, Wellington, 6021 New Zealand; E-mail: D.S.Rowlands@massey.ac.nz.
Submitted for publication May 2017.
Accepted for publication August 2017.