Effects of moderate-severe exercise on blood glucose in Type 1 diabetic adolescents treated with insulin pump or glargine insulin

Effects of HIIT Interventions on Cardiorespiratory Fitness and Glycemic Parameters in Adults with Type 1 Diabetes: A Systematic Review and Meta-Analysis

BACKGROUND

Individuals with type 1 diabetes mellitus (T1DM) face impaired cardiorespiratory fitness and glycemic control, increasing the risk of cardiovascular complications. High-intensity interval training (HIIT) has emerged as a promising exercise modality with potential benefits for both aspects in this population.

OBJECTIVES

The primary aim was to investigate the effects of HIIT on cardiorespiratory fitness and glycemic parameters in patients with T1DM. The secondary aim was to examine the most effective HIIT protocol for cardiorespiratory fitness and glycemic parameters in patients with T1DM.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

Two major electronic databases (Web of Science and PubMed) were searched up to February 2024.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Randomized and non-randomized trials involving adult patients with T1DM, free of complications and other diseases examining the effects of HIIT (HIIT pre vs. post; HIIT vs. control group or HIIT vs. moderate-intensity continuous training (MICT)) on cardiorespiratory fitness and glycemic parameters were included.

RESULTS

A total of ten studies met the inclusion criteria. The meta-analysis revealed a significant improvement in cardiorespiratory fitness following HIIT interventions (pre vs. post) in patients with T1DM (standardized mean difference (SMD) = 0.59, 95% confidence interval (CI) = 0.16 to 1, p = 0.01). Furthermore, HIIT (pre vs. post) was associated with significant improvements in 24-h mean glucose control (SMD = - 0.44, 95% CI = - 0.81 to - 0.06, p = 0.02), but the results (pre vs. post) failed to identify significant improvements in fasting glucose (SMD = - 0.26, 95% CI = - 0.78 to 0.24, p = 0.3) and glycated hemoglobin (HbA1C) values (SMD = - 0.28, 95% CI = - 0.61 to 0.05, p = 0.1). However, in comparison with a control group, HIIT showed significantly favorable effects on HbA1C (SMD = - 0.74, 95% CI = - 1.35 to - 0.14, p = 0.02). Finally, the meta-regression analysis did not find any moderating effect of any HIIT characteristics (i.e., intervention duration, session duration, work time, rest time, number of bouts, and intensity) on cardiorespiratory fitness and glycemic parameters.

CONCLUSION

Our systematic review and meta-analysis show that T1DM patients who performed a HIIT intervention significantly improved cardiorespiratory fitness and reduced their 24-h mean glucose levels, but not their HbA1C and fasting glucose. These findings support the application of HIIT interventions in T1DM patients. However, the guidelines for the most effective protocol remain unclear; hence, future studies are needed.

Predicting Hypoglycemia and Hyperglycemia Risk During and After Activity for Adolescents with Type 1 Diabetes

Objective: To predict hypoglycemia and hyperglycemia risk during and after activity for adolescents with type 1 diabetes (T1D) using real-world data from the Type 1 Diabetes Exercise Initiative Pediatric (T1DEXIP) study. Methods: Adolescents with T1D (n = 225; [mean ± SD] age = 14 ± 2 years; HbA1c = 7.1 ± 1.3%; T1D duration = 5 ± 4 years; 56% using hybrid closed loop), wearing continuous glucose monitors (CGMs), logged 3738 total activities over 10 days. Repeated Measures Random Forest (RMRF) and Repeated Measures Logistic Regression (RMLR) models were used to predict a composite risk of hypoglycemia (<70 mg/dL) and hyperglycemia (>250 mg/dL) within 2 h after starting exercise. Results: RMRF achieved high precision predicting composite risk and was more accurate than RMLR Area under the receiver operating characteristic curve (AUROC 0.737 vs. 0.661; P < 0.001). Activities with minimal composite risk had a starting glucose between 132 and 160 mg/dL and a glucose rate of change at activity start between -0.4 and -1.9 mg/dL/min. Time <70 mg/dL and time >250 mg/dL during the prior 24 h, HbA1c level, and insulin on board at activity start were also predictive. Separate models explored factors at the end of activity; activities with glucose between 128 and 133 mg/dL and glucose rate of change between 0.4 and -0.6 mg/dL/min had minimal composite risk. Conclusions: Physically active adolescents with T1D should aim to start exercise with an interstitial glucose between 130 and 160 mg/dL with a flat or slightly decreasing CGM trend to minimize risk for developing dysglycemia. Incorporating factors such as historical glucose and insulin can improve prediction modeling for the acute glucose responses to exercise.

Flexible insulin therapy with a hybrid regimen of insulin degludec and continuous subcutaneous insulin infusion with pump suspension before exercise in physically active adults with type 1 diabetes (FIT Untethered): a single-centre, open-label, proof-of-concept, randomised crossover trial

BACKGROUND

People with type 1 diabetes who use continuous subcutaneous insulin infusion (CSII, or insulin pump therapy) often remove their pump before extended periods of exercise, but this approach might result in reduced glycaemic control and increased risk of hyperglycaemia and ketogenesis. We aimed to assess the efficacy and safety of a hybrid approach, in which basal insulin delivery was divided between CSII and a daily injection of insulin degludec.

METHODS

In this single-centre, open-label, proof-of-concept, randomised crossover trial done at the LMC Diabetes & Endocrinology research centre, we recruited physically active and aerobically fit participants aged 18 years or older with type 1 diabetes who were using CSII. Participants were randomly assigned (1:1) by use of a computer-generated sequence to one of two sequences of either usual CSII, involving the continuation of the participant's usual CSII regimen, followed by crossover to hybrid CSII, in which the delivery of the participant's usual daily basal insulin dose was split (50% delivered by CSII and 50% delivered by a once-daily morning injection of 100 U/mL insulin degludec), or the opposite sequence (ie, hybrid CSII followed by crossover to usual CSII). Treatment was not masked to the investigators or participants. For each intervention, participants completed a moderate-intensity and a high-intensity in-clinic exercise session in the first week, followed by four high-intensity and two moderate-intensity home-based exercise sessions in the subsequent 3 weeks. Insulin pumps were suspended or disconnected 60 min before exercise and reconnected immediately after exercise during both treatment regimens. The coprimary outcomes were: (1) time spent in the target control range of 4·0-10·0 mmol/L blood glucose after high-intensity exercise, and (2) time spent in target control range of 4·0-10·0 mmol/L blood glucose after moderate-intensity exercise, measured by continuous glucose monitoring in the 6-h period from the start of the high-intensity and moderate-intensity in-clinic exercise sessions. Outcomes were assessed in a modified intention-to-treat population that included all participants who started both intervention phases and completed all of the in-clinic exercise visits. This trial is registered with ClinicalTrials.gov, NCT03838783, and is complete.

FINDINGS

Between May 15, 2018, and March 5, 2019, we assessed 43 patients for eligibility, of whom 31 were randomly assigned to receive the usual CSII regimen (n=14) or hybrid CSII regimen (n=17) in the first phase (before crossover). The analysis population consisted of 24 participants who completed both study phases. Compared with the usual CSII regimen, participants on the hybrid CSII regimen had a significantly longer time in blood glucose range of 4-10 mmol/L during the 6-h period from the start of both moderate-intensity (mean difference 86 min [95% CI 61-147], p=0·005; percentage time in range 64% [SD 35] vs 40% [35]) and high-intensity in-clinic exercise session (60 min [11-109], p=0·01; 66% [32] vs 50% [27]). Participants on the hybrid CSII regimen also showed a higher time in blood glucose range of 4-10 mmol/L during home-based exercise sessions (mean difference 23 min [95% CI -1 to 46], p=0·055), with significantly lower time spent in hyperglycaemia than participants on the usual CSII regimen (mean difference 25 min [2-48], p=0·04). These exploratory outcomes also showed no significant difference in the amount of time spent in hypoglycaemia, nor the number of hypoglycaemic events, between the two interventions. There were three study-related adverse events reported with the usual CSII regimen (two hypotension events and one nausea event) and four with the hybrid CSII regimen (two hypotension events and two nausea events).

INTERPRETATION

A hybrid regimen of injected insulin degludec and CSII (with pump removal during exercise) appears to be safe and effective in adults with type 1 diabetes who exercise regularly. This approach could offer improved glycaemic control immediately after exercise and should be further assessed in a larger-scale randomised trial.

FUNDING

Novo Nordisk.

Avoiding hypoglycemia: the use of insulin pump combined with continuous glucose monitor in type 1 diabetes crossing a Rocky Gorge

BACKGROUND

Continuous subcutaneous insulin infusion (CSII) and continuous glucose monitoring systems (CGMS) have been proven very effective in diabetes management.

AIM

This study evaluated the usefulness of these devices during prolonged, intense physical activity in an uncontrolled natural environment away from the clinical research center.

DESIGN

Non-randomized, prospective and observational study.

METHODS

During the summer, 38 participants with type 1 diabetes crossed the Samaria gorge, the second largest gorge in Europe (17 km). Twenty subjects on CSII combined with real-time CGMS and 18 on multiple daily injections (MDI) combined with professional (retrospective) CGMS participated in the program. All participants were unsupervised during the event.

RESULTS

All 38 participants managed to reach the destination point safely. There were no episodes of severe hypoglycemia. The duration of the exercise (mean ±SD) was 6.4 ± 1.3 h. The CSII group exhibited significantly lower hypoglycemic episodes during exercise (0.1 ± 0.3 vs. 0.4 ± 0.6; P = 0.047) as well as lower AUC below 70 mg/dl compared with the MDI, during the 24 h (0.61 ± 0.78 vs. 1.84 ± 1.55; P = 0.007). Individuals on CSII were significantly less likely to develop a hypoglycemic episode during exercise (P = 0.038). Exercise induced nocturnal hypoglycemia was not prevented effectively in neither group.

CONCLUSIONS

CSII combined with CGMS is effective in controlling blood glucose levels in type 1 diabetics who perform prolonged strenuous exercise. The use of insulin pump technology in regions with hot Mediterranean climates is safe and can provide protection against exercise-induced hypoglycemia. Development of precise instructions for T1DM who occasionally get involved in exercise activities, requires further studies.

Insulin Management Strategies for Exercise in Diabetes

There is no question that regular exercise can be beneficial and lead to improvements in overall cardiovascular health. However, for patients with diabetes, exercise can also lead to challenges in maintaining blood glucose balance, particularly if patients are prescribed insulin or certain oral hypoglycemic agents. Hypoglycemia is the most common adverse event associated with exercise and insulin therapy, and the fear of hypoglycemia is also the greatest barrier to exercise for many patients. With the appropriate insulin dose adjustments and, in some cases, carbohydrate supplementation, blood glucose levels can be better managed during exercise and in recovery. In general, insulin strategies that help facilitate weight loss with regular exercise and recommendations around exercise adjustments to prevent hypoglycemia and hyperglycemia are often not discussed with patients because the recommendations can be complex and may differ from one individual to the next. This is a review of the current published literature on insulin dose adjustments and starting-point strategies for patients with diabetes in preparation for safe exercise.

Pre-exercise blood glucose affects glycemic variation of aerobic exercise in patients with type 2 diabetes treated with continuous subcutaneous insulin infusion

AIMS

Considering the insulin sensitivity may increase by exercise particularly in patients with type 2 diabetes (T2D), glycemic variation during exercise needs to be studied when the patients are treated with insulin. This study aimed to explore the influence factors of the efficacy and safety of aerobic exercise in patients with T2D treated with Continuous Subcutaneous Insulin Infusion (CSII).

METHODS

A total of 267 patients with T2D, treated with CSII, were included. Glycemic variations were assessed by continuous glucose monitoring (CGM). Patients were asked to complete 30 min aerobic exercise for at least one time during CGM. The patients were divided into effective and ineffective group by incremental glucose area under curve from 0 to 60 min after exercise (AUC0-60 min).

RESULTS

The patients completed a total of 776 times of aerobic exercises. Blood glucose decreased fastest in the first 60 min of exercise. Pre-exercise blood glucose (PEBG) was negatively correlated with AUC0-60 min (standardized β = -0.386, P < 0.001) and incremental AUC of blood glucose ≤ 4.4 mmol/L (standardized β = -0.078, P = 0.034), and was significantly higher in effective group than in ineffective group (P < 0.001). The Δglucose AUC0-60 min during post-dinner was significantly higher than that during pre-lunch, post-lunch and pre-dinner (P < 0.05 for all).

CONCLUSIONS

PEBG is positively correlated with efficacy of aerobic exercise. Aerobic exercise will not worsen hyperglycemia when the PEBG > 16.7 mmol/L. Post-dinner exercise decreases the blood glucose better than other periods of the day.

CLINICAL TRIALS REGISTRATION

ChiCTR-ONC-17010400, www.chictr.org.cn.

Outcomes of algorithm-based modifications of insulinotherapy during exercise in MDI vs insulin pump-treated children with type 1 diabetes: Results from the TREAD-DIAB study

OBJECTIVES

To evaluate the evolution of subcutaneous glucose (SG) after a standardized aerobic exercise in children and adolescents treated with continuous subcutaneous insulin infusion (CSII) or multiple daily injection (MDI) regimen before and after adaptation of insulin doses.

RESEARCH DESIGN AND METHODS

Eleven CSII- and 13 MDI-treated patients performed 2 30-minute sessions of moderate to vigorous (70% of age-based maximal heart rate) exercise on a treadmill under continuous glucose monitoring (CGM). First sessions were scheduled without insulin modification (TT#1) while patients performed second sessions (TT#2) after preemptive algorithm-based insulin dose modifications.

RESULTS

While insulin adaptations did not modify immediate postexercise drops in blood glucose during TT#2 in either group, CSII-treated patients had their glucose control improved during TT#2 (mean of 141 ± 56 mg/dL vs 144 ± 80 mg/dL in TT#1; P < .05) with up to 86% of SG levels within targets during 16 hours postexercise. Contrarily, SG levels did not normalize during TT#2 in MDI-treated patients who experienced higher rates of hyperglycemia during the afternoon snack. As compared with TT#1, CSII-treated patients had reduced rates of hypoglycemia during 4 hours post-TT#2 (from 19.5% to 2.1%; P < .01) and had shorter duration of nocturnal hypoglycemia (35.5 ± 12.8 vs 204.7 ± 165 minutes; P = .04) whereas in the MDI group no changes in percentages of hypoglycemia were observed during TT#2.

CONCLUSION

In our pediatric cohort, algorithmic adaptations of insulin doses were associated with better outcomes in terms of postexercise glucose control in patients with CSII therapy but not with MDI treatment.

Why should people with type 1 diabetes exercise regularly?

Plethoric evidence reminds of the protective effects of exercise against a number of health risks, across all ages, in the general population. The benefits of exercise for individuals with type 2 diabetes are indisputable. An in-depth understanding of energy metabolism has reasonably entailed exercise as a cornerstone in the lifestyle of almost all subjects with type 1 diabetes. Nevertheless, individuals with type 1 diabetes often fail in accomplishing exercise guidelines and they are less active than their peer without diabetes. Two major obstacles are feared by people with type 1 diabetes who wish to exercise regularly: management of blood glucose control and hypoglycemia. Nowadays, strategies, including glucose monitoring technology and insulin pump therapy, have significantly contributed to the participation in regular physical activity, and even in competitive sports, for people with type 1 diabetes. Novel modalities of training, like different intensity, interspersed exercise, are as well promising. The beneficial potential of exercise in type 1 diabetes is multi-faceted, and it has to be fully exploited because it goes beyond the insulin-mimetic action, possibly through immunomodulation.

Continuous subcutaneous insulin infusion in diabetes: patient populations, safety, efficacy, and pharmacoeconomics

The level of glycaemic control necessary to achieve optimal short-term and long-term outcomes in subjects with type 1 diabetes mellitus (T1DM) typically requires intensified insulin therapy using multiple daily injections or continuous subcutaneous insulin infusion. For continuous subcutaneous insulin infusion, the insulins of choice are the rapid-acting insulin analogues, insulin aspart, insulin lispro and insulin glulisine. The advantages of continuous subcutaneous insulin infusion over multiple daily injections in adult and paediatric populations with T1DM include superior glycaemic control, lower insulin requirements and better health-related quality of life/patient satisfaction. An association between continuous subcutaneous insulin infusion and reduced hypoglycaemic risk is more consistent in children/adolescents than in adults. The use of continuous subcutaneous insulin infusion is widely recommended in both adult and paediatric T1DM populations but is limited in pregnant patients and those with type 2 diabetes mellitus. All available rapid-acting insulin analogues are approved for use in adult, paediatric and pregnant populations. However, minimum patient age varies (insulin lispro: no minimum; insulin aspart: ≥2 years; insulin glulisine: ≥6 years) and experience in pregnancy ranges from extensive (insulin aspart, insulin lispro) to limited (insulin glulisine). Although more expensive than multiple daily injections, continuous subcutaneous insulin infusion is cost-effective in selected patient groups. This comprehensive review focuses on the European situation and summarises evidence for the efficacy and safety of continuous subcutaneous insulin infusion, particularly when used with rapid-acting insulin analogues, in adult, paediatric and pregnant populations. The review also discusses relevant European guidelines; reviews issues that surround use of this technology; summarises the effects of continuous subcutaneous insulin infusion on patients' health-related quality of life; reviews relevant pharmacoeconomic data; and discusses recent advances in pump technology, including the development of closed-loop 'artificial pancreas' systems. © 2015 The Authors. Diabetes/Metabolism Research and Reviews Published by John Wiley & Sons Ltd.

Insulin pump therapy is associated with less post-exercise hyperglycemia than multiple daily injections: an observational study of physically active type 1 diabetes patients

BACKGROUND

Aerobic exercise typically decreases blood glucose levels in individuals with type 1 diabetes. It is currently unknown if glucose responses to exercise and recovery differ between patients on multiple daily insulin injections (MDI) and continuous subcutaneous insulin infusion (CSII).

SUBJECTS AND METHODS

Nineteen (16 male, three female) physically active individuals with type 1 diabetes took part in this observational study. Interstitial glucose levels (blinded) were compared during 45 min of standardized aerobic exercise (cycling or running at 60% peak aerobic capacity) and during 6 h of postexercise recovery between individuals using MDI (n=9) and CSII (n=10) therapy.

RESULTS

Both MDI and CSII groups had similar reductions in glucose levels during exercise, but responses in early and late recovery differed (group × time interaction, P<0.01). Participants using MDI had greater increases in glucose throughout recovery compared with individuals with CSII. Two-thirds of the MDI patients experienced late-onset post-exercise hyperglycemia (blood glucose >12 mmol/L) compared with only 1/10(th) of the CSII patients (P<0.01).

CONCLUSIONS

Among individuals performing regular moderate-to-heavy intensity aerobic exercise, use of CSII helped to limit post-exercise hyperglycemia compared with MDI therapy and is not associated with increased risk for post-exercise late-onset hypoglycemia.