Effects of different types of acute and chronic (training) exercise on glycaemic control in type 1 diabetes mellitus: a meta-analysis

Effects of postprandial exercise on blood glucose levels in adults with type 1 diabetes: a review

People with type 1 diabetes experience challenges in managing blood glucose around exercise. Previous studies have examined glycaemic responses to different exercise modalities but paid little attention to participants' prandial state, although this is an important consideration and will enhance our understanding of the effects of exercise in order to improve blood glucose management around activity. This review summarises available data on the glycaemic effects of postprandial exercise (i.e. exercise within 2 h after a meal) in people with type 1 diabetes. Using a search strategy on electronic databases, literature was screened until November 2022 to identify clinical trials evaluating acute (during exercise), subacute (≤2 h after exercise) and late (>2 h to ≤24 h after exercise) effects of postprandial exercise in adults with type 1 diabetes. Studies were systematically organised and assessed by exercise modality: (1) walking exercise (WALK); (2) continuous exercise of moderate intensity (CONT MOD); (3) continuous exercise of high intensity (CONT HIGH); and (4) interval training (intermittent high-intensity exercise [IHE] or high-intensity interval training [HIIT]). Primary outcomes were blood glucose change and hypoglycaemia occurrence during and after exercise. All study details and results per outcome were listed in an evidence table. Twenty eligible articles were included: two included WALK sessions, eight included CONT MOD, seven included CONT HIGH, three included IHE and two included HIIT. All exercise modalities caused consistent acute glycaemic declines, with the largest effect size for CONT HIGH and the smallest for HIIT, depending on the duration and intensity of the exercise bout. Pre-exercise mealtime insulin reductions created higher starting blood glucose levels, thereby protecting against hypoglycaemia, in spite of similar declines in blood glucose during activity between the different insulin reduction strategies. Nocturnal hypoglycaemia occurred after higher intensity postprandial exercise, a risk that could be diminished by a post-exercise snack with concomitant bolus insulin reduction. Research on the optimal timing of postprandial exercise is inconclusive. In summary, individuals with type 1 diabetes exercising postprandially should substantially reduce insulin with the pre-exercise meal to avoid exercise-induced hypoglycaemia, with the magnitude of the reduction depending on the exercise duration and intensity. Importantly, pre-exercise blood glucose and timing of exercise should be considered to avoid hyperglycaemia around exercise. To protect against late-onset hypoglycaemia, a post-exercise meal with insulin adjustments might be advisable, especially for exercise in the evening or with a high-intensity component.

Considerations in the Care of Athletes With Type 1 Diabetes Mellitus

Type 1 diabetes mellitus is an autoimmune disease caused by affected individuals’ autoimmune response to their own pancreatic beta-cell. It affects millions of people worldwide. Exercise has numerous health and social benefits for patients with type 1 diabetes mellitus; however, careful management of blood glucose is crucial to minimize the risk of hypoglycemia and hyperglycemia. Anaerobic and aerobic exercises cause different glycemic responses during and after exercise, each of which will affect athletes’ ability to reach their target blood glucose ranges. The optimization of the patient’s macronutrient consumption, especially carbohydrates, the dosage of basal and short-acting insulin, and the frequent monitoring of blood glucose, will enable athletes to perform at peak levels while reducing their risk of dysglycemia. Despite best efforts, hypoglycemia can occur. Recognition of symptoms and rapid treatment with either fast-acting carbohydrates or glucagon is important. Continuous glucose monitoring devices have become more widely used in preventing hypoglycemia.

The Effect of Aerobic Exercise Training on Plasma Apelin Levels and Pain Threshold in T1DM Rats

Background

Diabetes mellitus (types 1 and 2) leads to secondary complications such as neuropathy, which reduce a patient’s quality of life. Apelin and its receptor, APJ, have been shown to have antinociceptive effects and to decrease blood glucose levels.

Objectives

The present experimental study was conducted in Iran and investigated the role of apelin, which is used to manage type 1 diabetes mellitus, during exercise training.

Materials and Methods

Male Wistar rats (n = 36) were assigned by simple random allocation to six groups (n = 6): non-diabetic (ND), diabetic (D), sedentary non-diabetic (SND), sedentary diabetic (SD), exercise non-diabetic (END), and exercise diabetic (ED). Diabetes was induced by a single subcutaneous injection of streptozotocin (50 mg/kg). Exercise training consisted of treadmill running 60 minutes/day × 5 days/week for 10 weeks. The tail-flick test was used to assess the thermal pain threshold, and an apelin enzyme immunoassay kit was utilized to assess plasma apelin levels.

Results

Plasma apelin level was higher (0.3 vs. 0.1, P < 0.0001) and the tail-flick latency was lower (2.2 vs. 3.8, P < 0.0001) in the D group than in the ND group. After the training program, plasma apelin levels decreased in the exercise groups, and the tail-flick latency increased in the ED group. No correlation was found between apelin blood concentrations and tail-flick latency following the training program in the ED group.

Conclusions

These findings suggest that apelin does not play any significant role in regulating the pain threshold in type 1 diabetes mellitus during exercise training.

Physical Activity Capture Technology With Potential for Incorporation Into Closed-Loop Control for Type 1 Diabetes

Physical activity is an important determinant of glucose variability in type 1 diabetes (T1D). It has been incorporated as a nonglucose input into closed-loop control (CLC) protocols for T1D during the last 4 years mainly by 3 research groups in single center based controlled clinical trials involving a maximum of 18 subjects in any 1 study. Although physical activity data capture may have clinical benefit in patients with T1D by impacting cardiovascular fitness and optimal body weight achievement and maintenance, limited number of such studies have been conducted to date. Clinical trial registries provide information about a single small sample size 2 center prospective study incorporating physical activity data input to modulate closed-loop control in T1D that are seeking to build on prior studies. We expect an increase in such studies especially since the NIH has expanded support of this type of research with additional grants starting in the second half of 2015. Studies (1) involving patients with other disorders that have lasted 12 weeks or longer and tracked physical activity and (2) including both aerobic and resistance activity may offer insights about the user experience and device optimization even as single input CLC heads into real-world clinical trials over the next few years and nonglucose input is introduced as the next advance.

Exercise and the Development of the Artificial Pancreas: One of the More Difficult Series of Hurdles

Regular physical activity (PA) promotes numerous health benefits for people living with type 1 diabetes (T1D). However, PA also complicates blood glucose control. Factors affecting blood glucose fluctuations during PA include activity type, intensity and duration as well as the amount of insulin and food in the body at the time of the activity. To maintain equilibrium with blood glucose concentrations during PA, the rate of glucose appearance (Ra) to disappearance (Rd) in the bloodstream must be balanced. In nondiabetics, there is a rise in glucagon and a reduction in insulin release at the onset of mild to moderate aerobic PA. During intense aerobic -anaerobic work, insulin release first decreases and then rises rapidly in early recovery to offset a more dramatic increase in counterregulatory hormones and metabolites. An "exercise smart" artificial pancreas (AP) must be capable of sensing glucose and perhaps other physiological responses to various types and intensities of PA. The emergence of this new technology may benefit active persons with T1D who are prone to hypo and hyperglycemia.

Effect of aerobic and anaerobic exercises on glycemic control in type 1 diabetic youths

AIM: To evaluate the long-term effect of aerobic and/or anaerobic exercise on glycemic control in youths with type 1 diabetes.

METHODS: Literature review was performed in spring and summer 2014 using PubMed/MEDLINE, Google Scholar, Scopus, and ScienceDirect with the following terms: aerobic, anaerobic, high-intensity, resistance, exercise/training, combined with glycemic/metabolic control, glycated haemoglobin A1c (HbA1c) and type 1 diabetes. Only peer-reviewed articles in English were included published in the last 15 years. It was selected from 1999 to 2014. Glycemic control was measured with HbA1c. Studies with an intervention lasting at least 12 wk were included if the HbA1c was measured before and after the intervention.

RESULTS: A total of nine articles were found, and they were published between the years of 2002-2011. The sample size was 401 diabetic youths (166 males and 235 females) with an age range of 10-19 years except one study, in which the age range was 13-30 years. Study participants were from Australia, Tunisia, Lithuania, Taiwan, Turkey, Brazilia, Belgium, Egypt and France. Four studies were aerobic-based, four were combined aerobic and anaerobic programs, and one compared aerobic exercise to anaerobic one. Available studies had insufficient evidence that any type of exercise or combined training would clearly improve the glycemic control in type 1 diabetic youth. Only three (two aerobic-based and one combined) studies could provide a significant positive change in glycemic control.

CONCLUSION: The regular physical exercise has several other valuable physiological and health benefits that justify the inclusion of exercise in pediatric diabetes treatment and care.

Moderate Intensity Training Impact on the Inflammatory Status and Glycemic Profiles in NOD Mice

The nonobese diabetic (NOD) mouse represents a well-established experimental model analogous to human type 1 diabetes mellitus (T1D) as it is characterized by progressive autoimmune destruction of pancreatic β-cells. Experiments were designed to investigate the impact of moderate-intensity training on T1D immunomodulation and inflammation. Under a chronic exercise regime, NOD mice were trained on a treadmill for 12 weeks (12 m/min for 30 min, 5 d/wk) while age-matched, control animals were left untrained. Prior to and upon completion of the training period, fed plasma glucose and immunological soluble factors were monitored. Both groups showed deteriorated glycemic profiles throughout the study although trained mice tended to be more compensated than controls after 10 weeks of training. An exercise-induced weight loss was detected in the trained mice with respect to the controls from week 6. After 12 weeks, IL-6 and MIP-1β were decreased in the trained animals compared to their baseline values and versus controls, although not significantly. Morphometric analysis of pancreata revealed the presence of larger infiltrates along with decreased α-cells areas in the control mice compared to trained mice. Exercise may exert positive immunomodulation of systemic functions with respect to both T1D and inflammation, but only in a stringent therapeutic window.