The mGAINS Trial: Exploring The Feasibility And Utility Of Continuous Glucose Monitoring During Resistance Training

Abstract

There is a growing interest in the use of continuous glucose monitoring (CGM) in the sport science field to inform training strategies and improve performance. These devices provide information on 24hr glucose control and glycemic variability (GV), which are associated with deleterious health outcomes independent from other measures of cardiometabolic health. Whether these devices are feasible and useful in the context of resistance training (RT) aimed at lean mass gain has yet to be explored. PURPOSE: To examine the feasibility of CGM use during RT and explore associations between 24hr glucose homeostasis, glycemic variability, and total body and lean mass gains in athletes participating in the mGAINS trial (Muscle Growth in Athletes In Combination with Nutritious Snacks) which combined RT with a modest energy surplus for 10 weeks. METHODS: 28 male (n=15) and female (n=13) athletes aged 25±6 y participated in a 10-week hypertrophy-based RT program (3 days/week, 60-120 min/d) and were provided a daily snack (500 kcal/snack) to be consumed in addition to their habitual diet. A CGM device was placed on the posterior side of the preferred arm (halfway between the olecranon and the acromion process) at baseline and during the last week of the RT intervention. Body composition was assessed using dual-energy x-ray absorptiometry at baseline and after training. RESULTS: Mean CGM wear period was 7±1 days at each time point. Device wear time active was 100%. After 10 weeks, total body mass increased by 2.1±1.3 kg with 1.5±1.1 kg as lean mass (both p<0.001). Mean 24hr glucose concentrations before and after the intervention were 88±9 (range: 66-107 mg/dl) and 90±11 (range: 72-113 mg/dL), respectively (p>0.05). Mean GV at the two time points was 18±3% (p>0.05). Change in 24hr glucose control was weakly/moderately associated with change in total body mass (r= -0.381, p=0.045), but the association between change in GV and change in lean mass did not reach significance (r= -0.351, p=0.067). CONCLUSION: CGM devices can be feasibly utilized during an intense RT program. An inverse correlation between total body mass gain and 24hr glucose concentrations may suggest that weight gained through RT in combination with a modest energy surplus improves 24hr glucose concentrations in athletes.