Closed-Loop Insulin Delivery for Adults with Type 1 Diabetes Undertaking High-Intensity Interval Exercise Versus Moderate-Intensity Exercise: A Randomized, Crossover Study

Abstract

Preliminary findings suggest that closed-loop glucose control is safe for people undertaking HIIE and MIE. However, the management of the postexercise rise in ketones secondary to counter-regulatory hormone-induced insulin resistance observed with HIIE may represent a challenge for closed-loop systems.

Optimal Insulin Correction Factor in Post–High-Intensity Exercise Hyperglycemia in Adults With Type 1 Diabetes: The FIT Study

“…Our findings indicate that in HIIT, ketone levels do not rise and actually decline during and after HIIT exercise. In contrast, a recent study with closed-loop insulin therapy found that ketone levels were largely unchanged during continuous and HIIT types of exercise but increased significantly in early recovery, particularly after HIIT (22). The contrast with our study is surprising, given that their participants were studied in a fed and bolused state and exercised at a much lower intensity.…”

“…Similar to findings in early investigations of high-intensity exercise (24), and more recent studies of resistance training (10) and of HIIT (3,4,22), we observed a clear and reproducible increase in glucose levels following HIIT that did not appear to diminish with repeated exposure. Not all studies investigating high-intensity exercise have confirmed this finding, and the inherent differences in study design are particularly hypothesis generating.…”

“…Importantly, the pattern of hyperglycemic response appears to be consistent in subjects studied in a fasted and low insulin state. In contrast, studies of subjects after a carbohydrate load, whether intravenous (25) or oral (26,27), with prior insulin bolusing, have consistently shown modest hyperglycemia or only a limitation of hypoglycemia (22), suggesting that either the prior carbohydrate load or the prior insulin may have a fundamental role in determining the postexercise glycemic response. Finally, where high-intensity exercise has been studied as a hypoglycemia prevention tool within otherwise moderate-intensity exercise, the results are not directly comparable (14).…”

The hypoglycemia associated autonomic failure triggered by exercise in the patients with “brittle” diabetes and the strategy for prevention

“…The glucose level of one participant fell to 3.4 mmol/L at the end of MIE, but the glucose levels after HIIE were ≥4.0 mmol/L. The mean plasma glucose was higher during HIIE exercise than in MIE, Which is consistent with the findings reported by Guelfi et al [12].…”

Integrated Insulin Pump and Continuous Glucose Monitoring Technology in Diabetes Care Today: A Perspective of Real-Life Experience With the Minimed™ 670G Hybrid Closed-Loop System

“…The general recommendation is to start the temp target 1 to 2 hours before exercise, extending it to 1 to 2 hours after exercise (40). A recent study showed the effects of moderate intensity and high-interval intensity exercise with protocols designed to have similar energy expenditure using the MiniMed 670G system (54). In this study, the exercise routine was started at least 3 hours postbreakfast; a 20 grams of carbohydrate snack without bolus was given if the pre-exercise sensor glucose was less than 144 to 180 mg/dL, and the temp target was extended from 120 minutes pre-exercise to 15 minutes postexercise.…”