Timing of resistance exercise, glucose control and exercise adaptations in people with type 1 diabetes: a randomised-controlled trial

The main role of muscle is to allow body movements via the generation of force, with the importance of this highlighted in conditions associated with muscle mass loss, such as sarcopenia. Additionally, skeletal muscle has a critical, but often overlooked, role in metabolism. Muscle strength is determined through a combination of multiple modifiable and non-modifiable factors. The primary non-modifiable factor is genetics with data indicating that hand grip strength is ~50% hereditable. On the modifiable side, the primary factors important for the maintenance of muscle mass/strength are nutrition, particularly sufficient protein intake, and physical activity, particularly resistance exercise which is even effective in nonagenarians. Resistance exercise has been shown, in a wide variety of populations, to be efficacious in increasing muscle mass and function, increasing basal metabolic rate, reducing blood pressure, improving blood lipids and glycaemic control. Indeed, a meta-analysis in 2011 found that resistance exercise training can result in a 0.6% reduction in HbA1c. It is perhaps not surprising, therefore, that as well as recommendations for participation in aerobic exercise people with type 1 diabetes are recommended to participate in resistance exercise on 2-3 non-consecutive days of the week. However, there have only been a handful of studies which have investigated the acute effects of resistance exercise on glucose control – with mixed findings reported. Our aim is to compare the effects of acute morning and afternoon resistance exercise on blood glucose levels and to compare the effects of morning and afternoon resistance exercise training on cardiometabolic health outcomes in people with type 1 diabetes.