Anticipated Basal Insulin Reduction to Prevent Exercise-Induced Hypoglycemia in Adults and Adolescents Living with Type 1 Diabetes

Impact of pre- and post-exercise strategies on hypoglycemic risk for two modalities of aerobic exercise among adults and adolescents living with type 1 diabetes using continuous subcutaneous insulin infusion: A randomized controlled trial

OBJECTIVE

We investigated strategies to mitigate hypoglycemic risk during and after different aerobic exercises in people with type 1 diabetes (pwT1D) using continuous subcutaneous insulin infusion.

RESEARCH DESIGN AND METHODS

Thirty-seven pwT1D (21 adults, 16 adolescents; HbA1c = 7.5 ± 1.0 %) participated in two post-absorptive (4-h post-meal) exercise sessions (60-min continuous moderate intensity [CONT] vs. intermittent [INT]). Pre-exercise basal rate reduction (BRR) was either 40 % or 80 %, 90 min before exercise. Post-exercise, participants undertook either a 20 % BRR for 10 h with 20 % reduced dinner bolus (INS) or a 45 g post-exercise carbohydrate (CHO) snack with a 50 % insulin bolus, and a 30 g bedtime CHO snack without bolus (snack).

RESULTS

While a similar number of hypoglycemic events (31 vs. 28) were observed between exercise modalities, CONT led to a greater decrease in blood glucose during exercise compared to INT (-3.1 ± 2.3, CONT vs. -2.7 ± 2.2 mmol/l, INT, P = 0.005). Changes in blood glucose during exercise (-3.0 ± 2.4, 40 %BRR vs. -2.8 ± 2.1 mmol/l, 80 %BRR, P = 0.076) and the number of hypoglycemic events (35 vs. 24) were similar between 40 % and 80 %BRR. Time in hyperglycemia was lower with INS compared to snack in the first 30 min after exercise, but no differences were observed for late recovery period or nighttime.

CONCLUSION

Compared to INT, CONT led to greater blood glucose decline without increasing hypoglycemia risk. A larger pre-exercise BRR did not further reduce hypoglycemia risk during exercise. Post-exercise INS and snack strategies led to comparable glucose profiles in pwT1D.

Assessing the influence of insulin type (ultra-rapid vs rapid insulin) and exercise timing on postprandial exercise-induced hypoglycaemia risk in individuals with type 1 diabetes: a randomised controlled trial

AIMS/HYPOTHESIS

The relationship between pre-meal insulin type, exercise timing and the risk of postprandial exercise-induced hypoglycaemia in people living with type 1 diabetes is unknown. We aimed to evaluate the effects of exercise timing (60 vs 120 min post meal) and different insulin types (aspart vs ultra-rapid aspart) on hypoglycaemic risk.

METHODS

This was a four-way crossover randomised trial including 40 individuals with type 1 diabetes using multiple daily injections (mean HbA1c 56 mmol/mol [7.4%]). Participants, who were recruited from the Montreal Clinical Research Institute, undertook 60 min cycling sessions (60% ofV ˙ O 2 peak ) after breakfast (60 min [EX60min] or 120 min [EX120min] post meal) with 50% of their usual insulin dose (aspart or ultra-rapid aspart). Eligibility criteria included age ≥18 years old, clinical diagnosis of type 1 diabetes for at least 1 year and HbA1c ≤80 mmol/mol (9.5%). Participants were allocated using sequentially numbered, opaque sealed envelopes. Participants were masked to their group assignment, and each participant was allocated a unique identification number to ensure anonymisation. The primary outcome was change in blood glucose levels between exercise onset and nadir.

RESULTS

Prior to exercise onset, time spent in hyperglycaemia was lower for EX60min vs EX120min (time >10.0 mmol/l: 56.6% [1.2-100%] vs 78.0% [52.7-97.9%]; p<0.001). The glucose reduction between exercise onset and nadir was less pronounced with EX60min vs EX120min (-3.8±2.7 vs -4.7±2.5 mmol/l; p<0.001). A similar number of hypoglycaemic events occurred during both exercise timings. Blood glucose between exercise onset and nadir decreased less with ultra-rapid aspart compared with aspart (-4.1±2.3 vs -4.4±2.8 mmol/l; p=0.037). While a similar number of hypoglycaemic events during exercise were observed, less post-exercise hypoglycaemia occurred with ultra-rapid aspart (n=0, 0%, vs n=15, 38%; p=0.003). No interactions between insulin types and exercise timings were found.

CONCLUSIONS/INTERPRETATION

EX60min blunted the pre-exercise glucose increase following breakfast and was associated with a smaller glucose reduction during exercise. Ultra-rapid aspart led to a smaller blood glucose reduction during exercise and might be associated with diminished post-exercise hypoglycaemia.

TRIAL REGISTRATION

ClinicalTrials.gov NCT03659799 FUNDING: This study was funded by Novo Nordisk Canada.

Investigating the Impact of Time of Day on Glycaemia in Response to Postprandial Supramaximal Sprints in Adults With Type 1

OBJECTIVES

In this study, we explore the impact of postprandial exercise timing (morning vs evening) on glycemia in individuals with type 1 diabetes (T1D) during short all-out sprints on a cycle ergometer.

METHODS

Ten healthy, physically sedentary male (n=7) and female (n=3) volunteers with T1D, 22.8±2.8 years of age, and with a diabetes duration of 9.7±5.5 years and glycated hemoglobin level of 8.6±1.2%, underwent comprehensive screening and assessment of their physical health and fitness status before study participation, under the guidance of a physician. Each participant underwent 2 postprandial exercise sessions on separate days: the first in the morning at 8:00 AM and the second in the evening at 8:00 PM, both conducted 60 minutes after a standardized meal.

RESULTS

Morning exercise showed a less pronounced reduction in plasma glucose (PG) levels compared with evening exercise (-2.01±1.24 vs -3.56±1.6 mmol/L, p=0.03). In addition, higher cortisol levels were observed in the morning vs evening (128.59±34 vs 67.79±26 ng/mL, p<0.001).

CONCLUSIONS

Morning repeated sprint exercise conducted in the postprandial state consistent with the protective effect of higher cortisol levels resulted in a smaller reduction in PG levels compared with evening exercise. This highlights the potential influence of exercise timing on glycemic responses and cortisol secretion in the management of T1D.

Glycemic Management Around Postprandial Exercise in People With Type 1 Diabetes: Challenge Accepted

CONTEXT

The precise glycemic impact and clinical relevance of postprandial exercise in type 1 diabetes (T1D) has not been clarified yet.

OBJECTIVE

This work aimed to examine acute, subacute, and late effects of postprandial exercise on blood glucose (BG).

METHODS

A randomized, controlled trial comprised 4 laboratory visits, with 24-hour follow-up at home. Participants included adults with T1D (n = 8), aged 44 ± 13 years, with body mass index of 24 ± 2.1. Intervention included 30 minutes of rest (CONTROL), walking (WALK), moderate-intensity (MOD), or intermittent high-intensity (IHE) exercise performed 60 minutes after a standardized meal. Main outcome measures included BG change during exercise/control (acute), and secondary outcomes included the subacute (≤2 h after) and late glycemic effects (≤24 h after).

RESULTS

Exercise reduced postprandial glucose (PPG) excursion compared to CONTROL, with a consistent BG decline in all patients for all modalities (mean declines -45 ± 24, -71 ± 39, and -35 ± 21 mg/dL, during WALK, MOD, and IHE, respectively (P < .001). For this decline, clinical superiority was demonstrated separately for each exercise modality vs CONTROL. Noninferiority of WALK vs MOD was not demonstrated, noninferiority of WALK vs IHE was demonstrated, and equivalence of IHE vs MOD was not demonstrated. Hypoglycemia did not occur during exercise. BG increased in the hour after exercise (more than after CONTROL; P < .001). More than half of participants showed hyperglycemia after exercise necessitating insulin correction. There were more nocturnal hypoglycemic events after exercise vs CONTROL (P < .05).

CONCLUSION

Postprandial exercise of all modalities is effective, safe, and feasible if necessary precautions are taken (ie, prandial insulin reductions), as exercise lowered maximal PPG excursion and caused a consistent and clinically relevant BG decline during exercise while there was no hypoglycemia during or shortly after exercise. However, there seem to be 2 remaining challenges: subacute postexercise hyperglycemia and nocturnal hypoglycemia.

Continuous moderate and intermittent high-intensity exercise in youth with type 1 diabetes: Which protection for dysglycemia?

AIM

From an early age, exercise is key to managing type 1 diabetes (T1D). However, hypoglycemia around aerobic exercise is a major barrier to physical activity in children. We explore whether intermittent high-intensity aerobic exercise (IHE), designed to mimic spontaneous childhood physical activity patterns, offers better protection against glycemic drop than continuous moderate-intensity exercise (CME).

METHODS

Five boys and 7 girls with T1D (9.8 ± 1.4y) performed ergo cycle-based randomized CME and IHE of identical duration and total mechanical load [50 %PWC170vs. 15sec(150 %PWC170)/30 sec passive recovery; both during two 10-min sets, 5 min in-between]. Capillary glycemia during exercise and interstitial glucose during recovery were compared between exercises and an inactive condition, controlling for baseline glycemia, carbohydrate and insulin.

RESULTS

The exercise-induced decrease in capillary glycemia was attenuated by 1.47 mmol·L-1 for IHE vs. CME (P < 0.05). No symptomatic hypoglycemic episodes occurred during exercises. Post-exercise time in hypoglycemia did not differ between conditions. During early recovery, CME reduced time spent > 16.7 mmol·L-1 compared with inactive days (P < 0.05; CME: 0 %; IHE: 16,7 %; INACTIVE: 41,7 %).

CONCLUSION

IHE appeared to limit the glycemic drop compared to CME. Performing 20-min CME or IHE was not associated with increased hypoglycemic risk compared to being inactive. CME appeared even transiently protective against serious hyperglycemia.

Practical Aspects and Exercise Safety Benefits of Automated Insulin Delivery Systems in Type 1 Diabetes

Regular exercise is essential to overall cardiovascular health and well-being in people with type 1 diabetes, but exercise can also lead to increased glycemic disturbances. Automated insulin delivery (AID) technology has been shown to modestly improve glycemic time in range (TIR) in adults with type 1 diabetes and significantly improve TIR in youth with type 1 diabetes. Available AID systems still require some user-initiated changes to the settings and, in some cases, significant pre-planning for exercise. Many exercise recommendations for type 1 diabetes were developed initially for people using multiple daily insulin injections or insulin pump therapy. This article highlights recommendations and practical strategies for using AID around exercise in type 1 diabetes.