Normand G. Boulé

People with type 1 diabetes are recommended to modify insulin dosing and/or carbohydrate intake before, during and after exercise to manage blood glucose levels and prevent hypoglycaemia. An exercise strategy that produces a more consistent glycaemic response may facilitate glycaemic management around exercise, thereby reducing barriers to exercise related to blood glucose concentration, such as fear of hypoglycaemia, for people with type 1 diabetes. The aim of this study was to compare the consistency of the glycaemic response to resistance exercise performed in the morning while fasted vs in the afternoon after eating. Twelve adults with type 1 diabetes, HbA_1c <85 mmol/mol (10.0%), aged 18-55 years and without contraindications to resistance exercise completed six identical resistance exercise sessions, three in the morning while fasted (AM-FAST) and three in the afternoon in a fed state (PM-FED). The six sessions were completed in a random order in an unblinded, crossover trial, supervised at the Physical Activity and Diabetes Laboratory at the University of Alberta. We compared the within-participant standard deviation (wpSD) of the capillary blood glucose response to AM-FAST vs PM-FED sessions. Capillary glucose was measured pre-exercise, immediately post exercise and 30 min after exercise. Continuous glucose monitoring data were analysed from immediately post exercise up to 24 h after exercise. The wpSD of the change in capillary glucose during exercise was lower for AM-FAST (1.0±1.1 mmol/l) than PM-FED (1.5±1.0 mmol/l; p=0.029). There was no difference in the wpSD between conditions during the subsequent 30 min seated recovery (p=0.76). During exercise capillary glucose increased by 1.4±1.9 mmol/l for AM-FAST and decreased by 0.9±2.3 mmol/l for PM-FED (p=0.017). There was a greater percentage of time in hyperglycaemia in the 6 h post-exercise period following AM-FAST vs PM-FED (56.7% [27.2, 67.9] vs 33.0% [22.6, 41.5]; p=0.003, respectively). The glycaemic response to AM-FAST was more consistent and characterised by increases in glucose concentration, whereas the glycaemic response to PM-FED was less consistent and produced decreases in glucose concentration. Performing resistance exercise while fasted may reduce barriers to exercise for people with type 1 diabetes due to a more consistent glycaemic response that is less likely to cause hypoglycaemia during exercise. ClinicalTrials.gov NCT05168488. Dexcom Canada provided in-kind funding in the form of Dexcom G6 transmitters, sensors and receivers. LifeScan Canada provided in-kind funding in capillary glucose testing strips. JEY was supported by a Heart and Stroke Foundation of Canada Alberta New Investigator Award.

Purpose: Exercise-nutrient timing is of interest for people with type 2 diabetes (T2D) as a potential method to optimize glycemic control. However, the optimal nutritional environment for exercise is not well understood over the long term. The Fasted Exercise for Type 2 Diabetes (FED) Trial compared 16 wk of fasted versus postprandial morning exercise on glycated hemoglobin (HbA1c) and liver proton density fat fraction (PDFF). Methods: Twenty adults with T2D were recruited and randomized to complete exercise after an overnight fast versus after their morning meal. Participants walked three mornings per week, progressing to 180 min·wk⁻¹ over 16 wk. Results: Groups were balanced with five males and five females each. Sixteen participants completed the trial (8 in each group, 50% female). Age, HbA1c, and PDFF were 59.8 ± 9.0 yr, 7.2 ± 0.7%, and 9.3 ± 4.1%, respectively. On average, both groups completed 98% of their walking sessions but there was no change in HbA1c (−0.2%, P = 0.588). However, one participant from each group had changes in their glucose-lowering medication during the trial, and when excluded, the fasted training group had greater improvements in HbA1c compared with the postprandial group (−0.3% vs 0.0%, P = 0.033). There was no difference in changes in liver PDFF between groups (−1.6% vs 0.3%, P = 0.221) but visceral fat and intramuscular fat decreased to a greater extent after fasted exercise. Conclusions: Although our study had a small sample size, it suggests that exercise after an overnight fast can have high adherence and represents an option for people with T2D to improve longer-term indicators of glycemia and ectopic fat depots.

Introduction: Sarcopenia is common in children after liver transplantation (LTx). Resistance training (RT) may be effective in combating sarcopenia.Objectives: The purpose of the study was to test the feasibility and impact of a 12‐week RT program on skeletal muscle mass (SMM), muscle strength, physical performance (PP), and child–parent perspectives about RT.Methods: Children (6–18 years) post‐LTx and healthy controls (HC) underwent progressive RT using resistance bands. SMM and adipose tissue (MRI: abdomen and thigh), muscle strength (handgrip, push‐ups, sit‐to‐stand), and PP (6‐minute walk test [6MWT], timed‐up‐and‐down‐stair test [TUDS]) were measured before and after 12‐weeks of RT.Results: Ten children post‐LTx (11.9 ± 3.5 years) and 13 HC (11.7 ± 3.9 years) participated. LTx children significantly increased abdominal SM‐index (+4.6% LTx vs. a −2.7% HC; p = 0.01) and decreased visceral adipose tissue‐index (−18% LTx vs. −0.8% HC; p = 0.04) compared to HC. No thigh SMI changes were noted. Significant increases in 6MWT distance (LTx; p = 0.04), number of push‐ups (p = 0.04), and greater reduction times for TUDS (−10.6% vs. +1.7%; p = 0.05) occurred after 12 weeks. Higher thigh muscle‐fat content was associated with worse physical performance. These results were impacted by adherence (≥75% vs. <75%) and family engagement.Conclusions: RT in children post‐LTx is feasible and effective. RT in children post‐LTx may alleviate adverse outcomes associated with sarcopenia.

Purpose of review: Exercise and diet are among the most studied behaviors that can affect blood glucose concentrations. Despite multiple studies examining these interventions in different populations and contexts, inconsistencies across studies have led to variable expectations. The purpose of this review is to more specifically examine how the timing of when exercise is performed in relation to meals can modify changes in glucose concentrations or insulin sensitivity. When possible, studies in type 2 diabetes are emphasized, but recent research in type 1 diabetes, obesity, and athletes is also considered. Recent findings: The effect of a single bout of exercise performed after an overnight fast is often comparable to that of postprandial exercise on 24 h mean glucose concentrations. However, there is recent evidence to suggest that in some situations, but not all, longer term metabolic adaptations can be more favorable when exercise is regularly performed in the fasted state. Summary: Exercise after an overnight fast can have different effects on glucose metabolism compared with postprandial exercise. The shorter term and longer term changes following fasting exercise can be relevant to those who are seeking greater glucoregulatory benefit from their exercise sessions, such as people with diabetes.

Fear of hypoglycemia is a major exercise barrier for people with type 1 diabetes (PWT1D). Consequently, although guidelines recommend starting exercise with blood glucose (BG) concentration at 7–10 mmol/L, PWT1D often start higher, potentially affecting hydration and serum electrolyte concentrations. To test this, we examined serum and urine electrolyte concentrations during aerobic exercise (cycling 45 min at 60%VO₂peak) in 12 PWT1D (10F/2M, mean ± SEM: age 29 ± 2.3 years, VO₂peak 37.9 ± 2.2 mL·kg⁻¹·min⁻¹) with starting BG levels: 8–10 (MOD), and 12–14 (HI) mmol/L. Age, sex, and fitness-matched controls without diabetes (CON) completed one exercise session with BG in the normal physiological range. Serum glucose was significantly higher during exercise and recovery in HI versus MOD (p = 0.0002 and p < 0.0001, respectively) and in MOD versus CON (p < 0.0001). During exercise and recovery, MOD and HI were not significantly different in serum insulin (p = 0.59 and p = 0.63), sodium (p = 0.058 and p = 0.08), potassium (p = 0.17 and p = 0.16), calcium (p = 0.75 and 0.19), and magnesium p = 0.24 and p = 0.09). Our findings suggest that exercise of moderate intensity and duration with higher BG levels may not pose an immediate risk to hydration or serum electrolyte concentrations for PWT1D.

TPS600 Background: Non-muscle invasive bladder cancer (NMIBC) accounts for about 75% of newly diagnosed bladder cancers. The treatment for NMIBC initially involves transurethral resection of the bladder tumor followed by six weeks of induction intravesical therapy. NMIBC has a high rate of recurrence (31-78%) and progression (15%). Moreover, bladder cancer and its treatments may affect patient functioning, quality of life, and increase the risk of cardiovascular mortality. Exercise is a safe and effective intervention for many cancer patients groups, however, no studies have examined exercise during intravesical therapy for NMIBC. Bladder cancer and exeRcise trAining during intraVesical thErapy (BRAVE) is the first phase II randomized controlled trial designed to evaluate the safety, feasibility, and preliminary efficacy of exercise for NMIBC patients during intravesical therapy. An exploratory aim is to track the short-term bladder cancer recurrence and progression rates for each trial arm. Methods: BRAVE has a target sample size of 66 men or women diagnosed with NMIBC undergoing intravesical therapy with chemotherapy or immunotherapy agents. Participants are being randomly assigned to usual care or exercise intervention, which consists of three supervised, high-intensity interval training sessions/week for 12-weeks. Safety is being evaluated by any adverse events during the physical fitness assessments or exercise sessions. Feasibility will be evaluated by eligibility, recruitment, adherence, and attrition rates. Preliminary efficacy endpoints are cardiorespiratory fitness assessed by peak oxygen consumption (VO_2peak) at 6-week (post-intravesical therapy) and 3-month surveillance cystoscopy; and complete response (CR), defined as negative cytology, imaging, and cystoscopy and, when indicated, a negative biopsy. CR will be assessed at 3-month and one-year surveillance cystoscopy follow-up. Statistical analyses will follow the intention-to-treat approach. Analysis of covariance will compare between-group VO_2peak differences at post-intervention (pre-cystoscopy). Study enrolment started May 24, 2021 and is ongoing. As of October 4, 2021, we have screened 17 NMIBC patients scheduled for intravesical therapy for eligibility; 16 (94%) were ineligible for medical (n = 11), language (n = 3), or location (n = 2) reasons. All the medical reasons included severe cardiovascular diseases. One eligible patient declined due to travel distance to the facility. In the face of a slower-than-expected recruitment rate, eligibility was extended to patients in the maintenance phases of treatment for NMIBC, where patients receive three weekly instillations of intravesical therapy. Clinical trial information: NCT04593862.