Fasted High-Intensity Interval and Moderate-Intensity Exercise Do Not Lead to Detrimental 24-Hour Blood Glucose Profiles

Abstract

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Effect of combining pre‐exercise carbohydrate intake and repeated short sprints on the blood glucose response to moderate‐intensity exercise in young individuals with Type 1 diabetes

“…Notably, however, any comparison should be made with caution because participants in the study by Guelfi et al were in a postprandial state after a bolus of fast-acting insulin, whereas the participants in the present study were in an overnight fasted state with no prior insulin bolus. These different experimental conditions may explain the absence of an exercise-mediated fall in blood glucose reported here, as others have shown similar findings when exercise is performed after a prolonged fast [15][16][17][18]. This absence of fall in blood glucose levels may result from peripheral glucose uptake being markedly diminished when exercise is performed under fasting compared to post-absorptive conditions [19,20].…”

“…Another unexpected finding is that without prior carbohydrate intake, moderate-intensity exercise with or without repeated sprints did not significantly affect blood glucose levels. These different experimental conditions may explain the absence of an exercise-mediated fall in blood glucose reported here, as others have shown similar findings when exercise is performed after a prolonged fast [15][16][17][18]. Our findings contrast with those of Guelfi et al [9], where moderate-intensity exercise, with and without repeated sprints, was shown to result in a significant fall in blood glucose level, albeit to a lesser extent with the latter.…”

Home‐based high‐intensity interval training reduces barriers to exercise in people with type 1 diabetes

“…Recent work from our laboratory demonstrated that, unlike traditional MICT, HIT does not cause acute reductions in blood glucose concentrations in people with T1D (Scott et al., , b). Furthermore, 6 weeks of HIT in people with T1D led to similar increases in peak oxygen uptake () compared with MICT (Scott et al., ), despite the weekly training volume being 54–90 min less during HIT than MICT.…”

“…Furthermore, 6 weeks of HIT in people with T1D led to similar increases in peak oxygen uptake () compared with MICT (Scott et al., ), despite the weekly training volume being 54–90 min less during HIT than MICT. However, during these studies (Scott et al., , b), HIT was performed in optimal conditions, with high levels of researcher supervision, meaning that the ‘real‐world’ potential of HIT for people with T1D was still unclear. Furthermore, the HIT protocol used a cycle ergometer, introducing additional barriers to exercise, such as difficulties with access to equipment or facilities (including distance and cost) and potential embarrassment owing to negative body image if performed within a gym setting (Brazeau et al., ; Lascar et al., ).…”

“…However, many people with T1D lead a sedentary lifestyle and fail to meet the physical activity guidelines (Makura, Nirantharakumar, Girling, Saravanan, & Narendran, ; Tielemans et al., ; Wadén et al., ), in part because of the challenge of managing blood glucose concentration around exercise and fear of hypoglycaemia (Brazeau, Rabasa‐Lhoret, Strychar, & Mircescu, ; Lascar et al., ; Scott et al., ). Examples of strategies designed to help people with T1D to manage their blood glucose during and after exercise include adding short periods of high‐intensity exercise to traditional moderate‐intensity exercise (Bussau, Ferreira, Jones, & Fournier, , ; Fahey et al., ; Guelfi, Ratnam, Smythe, Jones, & Fournier, ); combining resistance training and endurance training (Yardley et al., ); the use of closed‐loop pump technology (Bally & Thabit, ); mini‐dose glucagon injections (Rickels et al., ); insulin adjustments and modifications to carbohydrate intake before and during exercise (McAuley et al., ; Moser et al., ; Zaharieva et al., ); and high‐intensity interval training (HIT; Scott et al., , b). Although many of these strategies show promise in facilitating blood glucose management during and after exercise, they do not target the many other common barriers to exercise that people with T1D face, such as difficulty with cost and travel time to gyms, limited access to exercise bikes and treadmills and a possible dislike for exercising in front of others in public gyms.…”