While intense endurance and resistance exercise training and whey protein supplementation have both been shown to independently improve glycaemic 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).
To determine if peri-training whey protein supplementation combined with MMIT can improve glycaemic control.
In a double-blind randomised controlled trial, 24 men (55.7±5.6 y) with T2D performed MMIT with whey (20 grams) or placebo control for 10 weeks. Glycaemic control was assessed via glucose disposal rate (GDR) during a euglycaemic insulin clamp, fasting blood glucose concentration (FBG), and HOMA-IR. Changes in peak oxygen consumption (VO2peak), 1-repetition maximum strength (1RM), Vastus lateralis (VL) muscle and subcutaneous adipose thicknesses (SAT), and waist circumference (WC) were also assessed.
10-weeks of MMIT substantially improved GDR by 27.5% (90%CI 1.2%, 60.7%) and 24.8% (-5.4%, 64.8%) in the whey and control groups, respectively. There were likely and possible reductions in FBG by -17.4% (-30.6%, -1.6) and HOMA-IR by -14.1% (-25.3%, 1.08%) in the whey group, however, whey effects were not clearly beneficial to glycaemic outcomes, relative to control. MMIT also clearly substantially improved 1RM by 20.6% (16.3%, 24.9%) and 22.7% (18.4%, 27.2%), VO2peak by 22.6% (12.0%, 26.2%) and 18.5% (10.5%, 27.4%), VL muscle thickness by 18.9% (12.0%, 26.2%) and 18.6% (10.5%, 27.4%) and possibly reduced WC by -2.1% (-3.1%, -1.0%) and -1.9% (-3.7%, -0.1%) in the control and whey groups respectively, but the whey-control outcome was trivial or unclear.
A clinically-meaningful enhancement in glycaemic control following 10-weeks of MMIT was not clearly advanced with peri-training whey protein supplementation in middle-aged men with Type-2 diabetes.
Correspondence: David S. Rowlands, School of Sport and Exercise, Massey University Wellington, 63 Wallace St, Wellington, New Zealand, Tel: +64 4 801 5799, D.S.Rowlands@massey.ac.nz
Clinical Trial Registration: ACTRN12613000340730.
Funding: School of Sport and Exercise Post-Graduate student project grant
Conflict of Interest: No author conflict of interest declared.
Accepted for Publication: 6 August 2017
© 2017 American College of Sports Medicine