Search

Objectives: This article compares metabolic, pancreatic, and gut-derived hormone responses to isomaltulose ingestion, before versus during submaximal sustained exercise, in adults with type 1 diabetes (T1D) using automated insulin delivery systems., Methods: In a randomized, cross-over trial, eight participants with T1D being treated with automated insulin pumps (five females, age: 47 ± 16 years, BMI: 27.5 ± 3.8 kg·m 2 , diabetes duration: 23 ± 11 years, HbA1c: 8.3 ± 0.9 [67.5 ± 9.5]% [mmol/mol]) attended the laboratory on two separate occasions and consumed an isocaloric amount of isomaltulose as either (1) a single serving (0.75g CHO·kg -1 BM) with a 25% reduction in bolus insulin 90 min before 45 min of cycling (PEC) or (2) three separate isocaloric servings (0.25g CHO·kg -1 BM each) without bolus insulin during exercise (DEC). Plasma glucose (PG), gut incretins (GLP-1 and GIP), pancreatic glucagon, exogenous insulin, and whole-body fuel oxidation rates were determined. Data were treated via a two-way repeated measures ANOVA, with p ≤ 0.05 accepted as significant., Results: PG concentrations throughout exercise were higher and less variable with DEC compared to PEC. The exercise-induced change in PG was directionally divergent between trials (PEC: ∆ - 3.2 ± 1.2 mmol/L vs. DEC: ∆ + 1.7 ± 1.5 mmol/L, p < 0.001), changing at a rate of -0.07 ± 0.03 mmol/L/min with PEC and +0.04 ± 0.03 mmol/L/min with DEC ( p < 0.001 between conditions). Throughout the exercise period, GLP-1, GIP, glucagon, and total insulin concentrations were lower with DEC (all p ≤ 0.02). The oxidation rates of carbohydrates were lower ( p = 0.009) and of lipids were greater ( p = 0.014) with DEC compared to PEC., Conclusions: The consumption of smaller servings of isomaltulose during, rather than as a single isocaloric serving before, submaximal sustained exercise provided (i) a better glycemic protective effect, (ii) a lesser push on pancreatic and gut-mediated glucoregulatory hormones, and (iii) a lower reliance on whole-body carbohydrate oxidation. Such information serves to remind us of the potential importance of nutrition for modulating the metabolic fate of an acute bout of exercise and may help inform best practice guidelines for exercise management in the T1D-sphere.

Aim: To evaluate and compare the plasma glucose (PG) response during spontaneous fasted morning moderate-intensity exercise with and without injection of subcutaneous glucagon in adults with type 1 diabetes (T1D) treated with an automated insulin delivery (AID) system., Methods: Ten adults (four female) with T1D (age 50 [42-67] years, diabetes duration: 22 [14-44] years, HbA1c: 55 [47-69] mmol/mol) treated with the MiniMed™ 780G AID system participated in a proof-of-concept two-period, crossover trial. Fasting participants undertook a 45 min bout of continuous moderate-intensity (~60% V̇O 2peak ) exercise on a cycle ergometer followed by 1 h of rest. Before exercise, 150-μg glucagon was administered subcutaneously on visit 1 (GLUC) but not on visit 2 (NO-GLUC). Temporary target on the AID was activated 15 min before until 15 min after exercise cessation. Blood samples were taken at 5- and 15-min intervals for measuring PG and biomarkers. Data were analysed using paired t tests or repeated measures ANOVA., Results: Time in range (3.9-10.0 mmol/L) was 100% on both study visits. No hypoglycaemia (<3.9 mmol/L) occurred in either arm. The GLUC arm had significantly higher mean PG (p = 0.01), area under the PG curve (p = 0.01), coefficient of variation (p < 0.01), peak PG (p = 0.01) and PG at the end of exercise (p < 0.01). No differences in endogenous glucoregulatory hormones were observed between visits., Conclusion: Adults with T1D treated with the MiniMed™ 780G can perform spontaneous fasted moderate-intensity exercise without hypoglycaemia. Therefore, glucagon was not needed for prevention of hypoglycaemia in such situations., (© 2024 John Wiley & Sons Ltd.)

Nine cyclists (age: 26 ± 5 years, height: 168 ± 5 cm and mass 58.5 ± 4.5 kg) were observed using continuous glucose monitoring devices throughout a training camp. Interstitial glucose [iG] data were captured via the Abbott libre sense biosensor (Abbott Laboratories) and paired with the Supersapiens software (TT1 Products Inc.). [iG] data were split into time ranges, that is, overall (24-hourly), day-time (06:00-23:59), night-time (00:00-05:59) and exercise. [iG] data were stratified into percentage of time, below range ([TBR] < 70 mg/dl), in range ([TIR] 70-140 mg/dl) and above range ([TAR] ≥ 141 mg/dl). Differences in diurnal and nocturnal data were analysed via repeated measures analysis of variance and paired t-tests where appropriate. p-value of ≤0.05 was accepted as significant. Riders spent an average of 3 ± 1% TAR, 93 ± 2% TIR and 8 ± 3% TBR. Mean 24 h [iG] was 93 ± 2 mg/dl with a coefficient of variation (CV) of 18 ± 1%. Mean (day: 95 ± 3 vs. night: 86 ± 3 mg/dl and p < 0.001) and CV (day: 18 ± 1 vs. night: 9 ± 1% and p < 0.001) in [iG] were higher during the day-time hours. TAR was greater during the day (day: 3 ± 1 vs. night: 0 ± 0% and p < 0.001) but TBR and TIR were similar. Glucose levels below the clinical range may have implications for those without diabetes and warrants further investigation., (© 2024 The Author(s). European Journal of Sport Science published by Wiley‐VCH GmbH on behalf of European College of Sport Science.)

Background: Automated insulin delivery (AID) systems offer promise in improving glycemic outcomes for individuals with type 1 diabetes. However, data on those who struggle with suboptimal glycemic levels despite insulin pump and continuous glucose monitoring (CGM) are limited. We conducted a randomized controlled trial to assess the effects of an AID system in this population., Methods: Participants with hemoglobin A 1c (HbA 1c ) ≥ 58 mmol/mol (7.5%) were allocated 1:1 to 14 weeks of treatment with the MiniMed 780G system (AID) or continuation of usual care (UC). The primary endpoint was change in time in range (TIR: 3·9-10·0 mmol/L) from baseline to week 14. After this trial period, the UC group switched to AID treatment while the AID group continued using the system. Both groups were monitored for a total of 28 weeks., Results: Forty adults (mean ± SD: age 52 ± 11 years, HbA 1c 67 ± 7 mmol/mol [8.3% ± 0.6%], diabetes duration 29 ±13 years) were included. After 14 weeks, TIR increased by 18.7% (95% confidence interval [CI] = 14.5, 22.9%) in the AID group and remained unchanged in the UC group ( P < .0001). Hemoglobin A 1c decreased by 10.0 mmol/mol (95% CI = 7.0, 13.0 mmol/mol) (0.9% [95% CI = 0.6%, 1.2%]) in the AID group but remained unchanged in the UC group ( P < .0001). The glycemic benefits of AID treatment were reproduced after the 14-week extension phase. There were no episodes of severe hypoglycemia or diabetic ketoacidosis during the study., Conclusions: For adults with type 1 diabetes not meeting glycemic targets despite use of insulin pump and CGM, transitioning to an AID system confers considerable glycemic benefits., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: MBC has received speaker honorarium from Sanofi and Novo Nordisk. KN holds shares in Novo Nordisk; has been a paid consultant for Novo Nordisk and Medtronic; has received speaker honorarium and honorarium for Advisory Board to her institution from Medtronic, Novo Nordisk, Convatec, and her institution has received research funding from Zealand Pharma, Novo Nordisk, Medtronic, and Dexcom. SS was an employee at Novo Nordisk A/S during study conduct and has received speaker fees from Novo Nordisk. KR own shares in Novo Nordisk and has received speaker’s honorarium from Medtronic. AGR and OMC have nothing to disclose.

By reducing carbohydrate intake, people with type 1 diabetes may reduce fluctuations in blood glucose, but the evidence in this area is sparse. The aim of this study was to investigate glucose metrics during a one-week low-carbohydrate-high-fat (HF) and a low-carbohydrate-high-protein (HP) diet compared with an isocaloric high-carbohydrate (HC) diet. In a randomized, three-period cross-over study, twelve adults with insulin-pump-treated type 1 diabetes followed an HC (energy provided by carbohydrate: 48%, fat: 33%, protein: 19%), HF (19%, 62%, 19%), and an HP (19%, 57%, 24%) diet for one week. Glucose values were obtained during intervention periods using a Dexcom G6 continuous glucose monitoring system. Participant characteristics were: 33% females, median (range) age 50 (22-70) years, diabetes duration 25 (11-52) years, HbA1c 7.3 (5.5-8.3)% (57 (37-67) mmol/mol), and BMI 27.3 (21.3-35.9) kg/m 2 . Glycemic variability was lower with HF (30.5 ± 6.2%) and HP (30.0 ± 5.5%) compared with HC (34.5 ± 4.1%) (P HF-HC = 0.009, P HP-HC = 0.003). There was no difference between groups in mean glucose (HF: 8.7 ± 1.1, HP: 8.2 ± 1.0, HC: 8.7 ± 1.0 mmol/L, P Overall = 0.08). Time > 10.0 mmol/L was lower with HP (22.3 ± 11.8%) compared with HF (29.4 ± 12.1%) and HC (29.5 ± 13.4%) (P HF-HP = 0.037, P HC-HP = 0.037). In conclusion, a one-week HF and, specifically, an HP diet improved glucose metrics compared with an isocaloric HC diet.

Context: Current guidelines for exercise-related glucose management focus on reducing bolus and/or basal insulin doses and considering carbohydrate intake. Yet far less attention has been paid to the potential role of other macronutrients alongside carbohydrates on glucose dynamics around exercise., Objective: To investigate the effects of a low-carbohydrate-high-protein (LCHP) compared with a high-carbohydrate-low-protein (HCLP) pre-exercise meal on the metabolic, hormonal, and physiological responses to exercise in adults with insulin pump-treated type 1 diabetes., Methods: Fourteen adults (11 women, 3 men) with insulin pump-treated type 1 diabetes (median [range] HbA1c of 50 [43-59] mmol/mol (6.7% [6.1%-7.5%]), age of 49 [25-65] years, and body mass index of 24.0 [19.3-27.1] kg/m2) completed an unblinded, 2-arm, randomized, crossover study. Participants ingested isocaloric meals that were either LCHP (carbohydrate 21%, protein 52%, fat 27%) or HCLP (carbohydrate 52%, protein 21%, fat 27%) 90 minutes prior to undertaking 45 minutes of cycling at moderate intensity. Meal insulin bolus was dosed according to meal carbohydrate content but reduced by 25%. Basal insulin rates were reduced by 35% from meal ingestion to end of exercise., Results: Around exercise the coefficient of variability was lower during LCHP (LCHP: 14.5 ± 5.3 vs HCLP: 24.9 ± 7.7%, P = .001). Over exercise, LCHP was associated with a lesser drop (LCHP: Δ-1.49 ± 1.89 vs HCLP: Δ-3.78 ± 1.95 mmol/L, P = .001). Mean insulin concentration was 30% lower during exercise for LCHP compared with HCLP (LCHP: 25.5 ± 11.0 vs HCLP: 36.5 ± 15.9 mU/L, P < .001)., Conclusion: Ingesting a LCHP pre-exercise meal lowered plasma glucose variability around exercise and diminished the drop in plasma glucose over exercise., (© The Author(s) 2023. Published by Oxford University Press on behalf of the Endocrine Society. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Aim: To assess the effectiveness of an automated insulin delivery (AID) system around exercise in adults with type 1 diabetes (T1D). Methods: This was a three-period, randomized, crossover trial involving 10 adults with T1D (hemoglobin A1C; HbA 1c : 8.3% ± 0.6% [67 ± 6 mmol/mol]) using an AID system (MiniMed 780G; Medtronic USA). Participants performed 45 min of moderate intensity continuous exercise 90 min after consuming a carbohydrate-based meal using three strategies: (1) a 100% dose of bolus insulin with exercise announcement immediately at exercise onset "spontaneous exercise" (SE) or a 25% reduced dose of bolus insulin with exercise announcement either (2) 90 min (AE90) or (3) 45 min (AE45) before exercise. Venous-derived plasma glucose (PG) taken in 5 and 15 min intervals over a 3 h collection period was stratified into the percentage of time spent below (TBR [<3.9 mmol/L]), time in range (TIR [3.9-10 mmol/L]), and time above range (TAR [ > 10 mmol/L]). In instances of hypoglycemia, PG data were carried forward for the remainder of the visit. Results: Overall, TBR was greatest during SE (SE: 22.9 ± 22.2, AE90: 1.1 ± 1.9, AE45: 7.8% ± 10.3%, P  = 0.029). Hypoglycemia during exercise occurred in four participants in SE but one in both AE90 and AE45 ( ꭓ 2 [2] = 3.600, P  = 0.165). In the 1 h postexercise period, AE90 was associated with higher TIR (SE: 43.8 ± 49.6, AE90: 97.9 ± 5.9, AE45: 66.7% ± 34.5%, P  = 0.033), lower TBR (SE: 56.3 ± 49.6, AE90: 2.1 ± 5.9, AE45: 29.2% ± 36.5%, P  = 0.041) with the greatest source of discrepancy observed relative to SE. Conclusion: In adults using an AID system and undertaking postprandial exercise, a strategy involving both bolus insulin dose reduction and exercise announcement 90 min before commencing the activity may be most effective in minimizing dysglycemia. The study was registered as a clinical trial (Clinical Trials Register; NCT05134025).

In an in-patient switch study, 10 adults with type 1 diabetes (T1D) performed 45 min of moderate-intensity exercise on 2 occasions: (1) when using their usual insulin pump (UP) and (2) after transitioning to automated insulin delivery (AID) treatment (MiniMed™ 780G). Consensus glucose management guidelines for performing exercise were applied. Plasma glucose concentrations measured over a 3-h monitoring period were stratified into time below range (TBR, <3.9 mmol/L), time in range (TIR, 3.9-10.0 mmol/L), and time above range (TAR, >10.0 mmol/L). Overall, TBR (UP: 11 ± 21 vs. AID: 3% ± 10%, P  = 0.413), TIR (UP: 53 ± 27 vs. AID: 66% ± 39%, P  = 0.320), and TAR (UP: 37 ± 34 vs. AID: 31% ± 41%, P  = 0.604) were similar between arms. A proportionately low number of people experienced exercise-induced hypoglycemia (UP: n  = 2 vs. AID: n  = 1, P  = 1.00). In conclusion, switching to AID therapy did not alter patterns of glycemia around sustained moderate-intensity exercise in adults with T1D. Clinical Trial Registration number: NCT05133765.

Aims: To profile acute glycaemic dynamics during graded exercise testing (GXT) and explore the influence of glycaemic indicators on the physiological responses to GXT in adults with type 1 diabetes using insulin pump therapy., Methods: This was a retrospective analysis of pooled data from four clinical trials with identical GXT protocols. Data were obtained from 45 adults with type 1 diabetes using insulin pumps [(30 females); haemoglobin A1c 59.5 ± 0.5 mmol/mol (7.6 ± 1.0%); age 49.7 ± 13.0 years; diabetes duration 31.2 ± 13.5 years; V̇O 2peak 29.5 ± 8.0 ml/min/kg]. Integrated cardiopulmonary variables were collected continuously via spiroergometry. Plasma glucose was obtained every 3 min during GXT as well as the point of volitional exhaustion. Data were assessed via general linear modelling techniques with age and gender adjustment. Significance was accepted at p ≤ .05., Results: Despite increasing duration and intensity, plasma glucose concentrations remained similar to rest values (8.8 ± 2.3 mmol/L) throughout exercise (p = .419) with an overall change of +0.3 ± 1.1 mmol/L. Starting glycaemia bore no influence on subsequent GXT responses. Per 1% increment in haemoglobin A1c there was an associated decrease in V̇O 2peak of 3.8 ml/min/kg (p < .001) and power peak of 0.33 W/kg (p < .001) concomitant with attenuations in indices of peripheral oxygen extraction [(O 2 pulse) -1.2 ml/beat, p = .023]., Conclusion: In adults with long-standing type 1 diabetes using insulin pump therapy, circulating glucose remains stable during a graded incremental cycle test to volitional exhaustion. Glycaemic indicators are inversely associated with aerobic rate, oxygen economy and mechanical output across the exercise intensity spectrum. An appreciation of these nexuses may help guide appropriate decision making for optimal exercise management strategies., (© 2022 The Authors. Diabetes, Obesity and Metabolism published by John Wiley & Sons Ltd.)

International charities and health care organizations advocate regular physical activity for health benefit in people with type 1 diabetes. Clinical expert and international diabetes organizations' position statements support the management of good glycemia during acute physical exercise by adjusting exogenous insulin and/or carbohydrate intake. Yet research has detailed, and patients frequently report, variable blood glucose responses following both the same physical exercise session and insulin to carbohydrate alteration. One important source of this variability is insulin delivery to the circulation. With modern insulin analogs, it is important to understand how different insulins, their delivery methods, and inherent physiological factors, influence the reproducibility of insulin absorption from the injection site into circulation. Furthermore, contrary to the adaptive pancreatic response to exercise in the person without diabetes, the physiological and metabolic shifts with exercise may increase circulating insulin concentrations that may contribute to exercise-related hyperinsulinemia and consequent hypoglycemia. Thus, a furthered understanding of factors underpinning insulin delivery may offer more confidence for healthcare professionals and patients when looking to improve management of glycemia around exercise., (Copyright © 2020 Pitt, McCarthy, Hoeg-Jensen, Wellman and Bracken.)