Search

Objectives: Current exercise recommendations for people with type 1 diabetes (T1D) are based on research involving primarily young, fit male participants. Recent studies have shown possible differences between male and female blood glucose response to exercise, but little is known about whether these differences are sex-related (due to physiological differences between male and female participants) or gender-related (behavioural differences between men and women)., Methods: To better understand gender-based behavioural differences surrounding physical activity (PA), we asked men and women (n=10 each) with T1D to participate in semistructured interviews. Topics discussed included motivation and barriers to exercise, diabetes management strategies, and PA preferences (type, frequency, duration of exercise, etc). Interview transcripts were coded by 2 analysts before being grouped into themes., Results: Six themes were identified impacting participants' PA experience: motivation, fear of hypoglycemia, time lost to T1D management, medical support for PA, the role of technology in PA accessibility, and desire for more community. Gender differences were found in motivations, medical support, and desire for more community. Women were more motivated by directional weight dissatisfaction, and men were more motivated to stay in shape. Men felt less supported by their health-care providers than women. Women more often preferred to exercise in groups, and sought more community surrounding T1D and PA., Conclusion: Although men and women with T1D experience similar barriers around PA, there are differences in motivation, desire for community, and perceived support from medical providers., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)

Objectives: Expert guidelines recommend an aerobic cooldown to lower blood glucose for the management of post-exercise hyperglycemia. This strategy has never been empirically tested. Our aim in this study was to compare the glycemic effects of performing an aerobic cooldown vs not performing a cooldown after a fasted resistance exercise session. We hypothesized that the cooldown would lower blood glucose in the 30 minutes after exercise and would result in less time in hyperglycemia in the 6 hours after exercise., Methods: Participants completed 2 identical resistance exercise sessions. One was followed by a low-intensity (30% of peak oxygen consumption) 10-minute cycle ergometer cooldown, and the other was followed by 10 minutes of sitting. We compared the changes in capillary glucose concentration during these sessions and continuous glucose monitoring (CGM) outcomes over 24 hours post-exercise., Results: Sixteen participants completed the trial. Capillary glucose was similar between conditions at the start of exercise (p=0.07). Capillary glucose concentration decreased by 0.6±1.0 mmol/L during the 10-minute cooldown, but it increased by 0.7±1.3 mmol/L during the same time in the no-cooldown condition. The resulting difference in glucose trajectory led to a significant interaction (p=0.02), with no effect from treatment (p=0.7). Capillary glucose values at the end of recovery were similar between conditions (p>0.05). There were no significant differences in CGM outcomes., Conclusions: An aerobic cooldown reduces glucose concentration in the post-exercise period, but the small and brief nature of this reduction makes this strategy unlikely to be an effective treatment for hyperglycemia occurring after fasted exercise., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)

Objectives: Evidence suggests that glucose levels in menstruating females with type 1 diabetes change throughout the menstrual cycle, reaching a peak during the luteal phase. The Type 1 Diabetes Exercise Initiative (T1DEXI) study provided the opportunity to assess glycemic metrics between early and late phases of the menstrual cycle, and whether differences could be explained by exercise, insulin, and carbohydrate intake., Methods: One hundred seventy-nine women were included in our analysis. Glycemic metrics, carbohydrate intake, insulin requirements, and exercise habits during the early vs late phases of their menstrual cycles (i.e. 2 to 4 days after vs 2 to 4 days before reported menstruation start date) were compared., Results: Mean glucose increased from 8.2±1.5 mmol/L (148±27 mg/dL) during the early follicular phase to 8.6±1.6 mmol/L (155±29 mg/dL) during the late luteal phase (p<0.001). Mean percent time-in-range (3.9 to 10.0 mmol/L [70 to 180 mg/dL]) decreased from 73±17% to 70±18% (p=0.002), and median percent time >10.0 mmol/L (>180 mg/dL) increased from 21% to 23% (p<0.001). Median total daily insulin requirements increased from 37.4 units during the early follicular phase to 38.5 units during the late luteal phase (p=0.02) and mean daily carbohydrate consumption increased slightly from 127±47 g to 133±47 g (p=0.05); however, the difference in mean glucose during early follicular vs late luteal phase was not explained by differences in exercise duration, total daily insulin units, or reported carbohydrate intake., Conclusions: Glucose levels during the late luteal phase were higher than those of the early follicular phase of the menstrual cycle. These glycemic changes suggest that glucose management for women with type 1 diabetes may need to be fine-tuned within the context of their menstrual cycles., (Copyright © 2024 Canadian Diabetes Association. Published by Elsevier Inc. All rights reserved.)

Objectives: Exercise-induced hyperglycemia is recognized in type 1 diabetes (T1D) clinical guidelines, but its association with high-intensity intermittent exercise (HIIE) in acute studies is inconsistent. In this meta-analysis, we examined the available evidence of blood glucose responses to HIIE in adults with T1D. The secondary, aim was to examine predictors of blood glucose responses to HIIE. We hypothesized that there would be no consistent effect on blood glucose from HIIE, unless examined in the context of participant prandial status., Methods: We conducted a literature search using key words related to T1D and HIIE. Studies were required to include at least 6 participants with T1D with a mean age >18 years, involve an HIIE intervention, and contain pre- and postexercise measures of blood glucose. Analyses of extracted data were performed using a general inverse variance statistical method with a random effects model and a weighted multiple regression., Results: Nineteen interventions from 15 reports were included in the analysis. A mean overall blood glucose decrease of -1.3 mmol/L (95% confidence interval [CI], -2.3 to -0.2 mmol/L) was found during exercise, albeit with high heterogeneity (I 2 =84%). When performed after an overnight fast, exercise increased blood glucose by +1.7 mmol/L (95% CI, 0.4 to 3.0 mmol/L), whereas postprandial exercise decreased blood glucose by -2.1 mmol/L (95% CI, -2.8 to -1.4 mmol/L), with a statistically significant difference between groups (p<0.0001). No associations with fitness (p=0.4), sex (p=0.4), age (p=0.9), exercise duration (p=0.9), or interval duration (p=0.2) were found., Conclusion: The effect of HIIE on blood glucose is inconsistent, but partially explained by prandial status., (Copyright © 2022 Canadian Diabetes Association. Published by Elsevier Inc. All rights reserved.)

Objectives: In individuals with type 1 diabetes (T1D), changes in blood glucose (BG) during high-intensity interval exercise (HIIE) are smaller than those observed during aerobic exercise. Study outcomes, however, have been variable, with some demonstrating significant BG decreases and others showing BG increases. This study compared BG outcomes between fasting (AME) and postprandial (PME) HIIE in T1D to test the hypothesis that AME would produce a BG increase, yet PME would cause BG to decline., Methods: Twelve (6 men and 6 women) physically active individuals with T1D performed two 45-minute exercise sessions (AME at 7:00 AM, PME at 5:00 PM) in random order, separated by at least 48 hours. Sessions consisted of a 10-minute warmup (50%VO 2peak ), followed by 10-second sprints every 2 minutes for 24 minutes, and then an 11-minute cooldown. Capillary glucose was measured pre- and postexercise, and then 60 minutes postexercise. Interstitial glucose was recorded for 24 hours postexercise using continuous glucose monitoring., Results: AME caused capillary glucose to increase (from 7.6±1.4 to 9.2±2.9 mmol/L during exercise, and 9.9±2.8 mmol/L in recovery), whereas PME produced a decline in capillary glucose (from 9.9±3.1 to 9.5±3.4 mmol/L during exercise and 8.9±2.7 mmol/L during recovery; time × treatment interaction, p=0.014). PME was associated with a higher frequency of hyperglycemic events in the 6 hours and overnight (midnight to 6:00 AM) after exercise., Conclusions: Fasting HIIE results in a different BG trajectory than postprandial exercise in T1D, and may be beneficial for hypoglycemia avoidance during exercise., (Copyright © 2020 Canadian Diabetes Association. Published by Elsevier Inc. All rights reserved.)

Objectives: It is well known that exercise can improve the glycemic profile in individuals with type 2 diabetes (T2D). However, the optimal timing of exercise is often debated. Our aim in this study was to compare the effects of exercise performed at different times of the day and different timing in relation to meals on 24-hour glucose profiles in people with T2D., Methods: Fourteen individuals with T2D were recruited and wore continuous glucose monitors for 12 days. During the 12 days, participants completed 4 conditions according to a randomized, crossover design: i) morning (fasting) exercise (MorEx), ii) afternoon exercise (AftEx), iii) evening exercise (EveEx) and iv) seated control. Exercise consisted of 50 minutes of walking at 5.0 km/h., Results: Eight men and 6 women (age, 65±9.0 years; T2D duration, 10.5±6.8 years; mean glycated hemoglobin, 6.7±0.6%) were included in the analysis. Mean 24-hour continuously monitored glucose was 7.4±0.7 mmol/L, 7.3±0.7 mmol/L, 7.5±0.8 mmol/L and 7.5±0.7 mmol/L in the MorEx, AftEx, EveEx and control conditions, respectively, with no significant differences among the 4 conditions (p=0.55). MorEx had a lower respiratory exchange ratio compared with AftEx and EveEx (p<0.01). The decrease in glucose during exercise was less pronounced for MorEx compared with AftEx (p<0.05)., Conclusions: Fifty minutes of walking at 3 different times of day and at different timing in relation to meals did not lower 24-hour glucose concentrations in people with T2D. The reasons why exercise was not effective at lowering glucose remain unclear., (Copyright © 2020 Canadian Diabetes Association. Published by Elsevier Inc. All rights reserved.)

Objectives: In adults with type 1 diabetes, resistance exercise (RE) is associated with more stable blood glucose (BG) levels than aerobic exercise, both during and after exercise. In individuals without diabetes, growth hormone and epinephrine responses to RE differ between the sexes. These hormones are known to affect BG levels in individuals with type 1 diabetes. In this study, we explored whether sex-related differences may exist in BG responses to RE in individuals with type 1 diabetes., Methods: A secondary data analysis was conducted on pooled data from 2 studies with identical RE protocols for individuals with type 1 diabetes (13 males, age range 16 to 63 years; 10 females, age range 19 to 45 years). The RE session consisted of 7 resistance-based exercises performed at 5 pm. Plasma glucose samples were collected before, immediately after and 1 h after exercise. Interstitial glucose levels were recorded through blinded continuous glucose monitoring 24 h before, during and 24 h after exercise., Results: There was a significant sex-by-time interaction (p<0.001) in plasma glucose responses to RE. Plasma glucose decreased significantly in males from 8.6±2.5 to 6.3±2.1 mmol/L (p<0.001) during exercise, whereas females experienced no significant change (7.2±1.3 to 7.3±1.3 mmol/L, p=0.999). In the 6 h after RE, males developed significantly more hypoglycemia, as measured by continuous glucose monitoring (p=0.048)., Conclusions: Males may have a greater risk of hypoglycemia with an acute bout of RE than females. Further research is needed to examine this phenomenon more closely, as sex-specific recommendations for preventing hypoglycemia around RE may be necessary in type 1 diabetes., (Copyright © 2019 Canadian Diabetes Association. Published by Elsevier Inc. All rights reserved.)

Objective: Recommendations for insulin adjustments and carbohydrate intake exist for individuals with type 1 diabetes who are undertaking moderate exercise. Very few guidelines exist for athletes with type 1 diabetes who are competing in events of higher intensity or longer duration. This observational study reports the strategies adopted by 6 habitually active men with type 1 diabetes (glycated hemoglobin = 8.3%±2.0%) undertaking a relatively intense endurance cycling event., Methods: Participants wore continuous glucose monitoring (CGM) sensors for 24 hours before competition, while racing and overnight postrace. They were asked to eat their regular meals and snacks and make their usual insulin adjustments before, during and after competition. All food intake and insulin adjustments were recorded in detail., Results: Participants used a variety of adjustments for exercise. Of 6 participants, 4 decreased their insulin dosages and all participants consumed carbohydrates during the race (mean = 87±57 g). In spite of these strategies, 3 of the 6 participants experienced mild to moderate hypoglycemia (not requiring assistance) during the event. Hyperglycemia was seen in all participants 3 hours postexercise. There were no incidents of nocturnal hypoglycemia., Conclusions: Individuals with type 1 diabetes can compete in intensive long-distance athletic events using a variety of nutrition- and insulin-adjustment strategies. In addition to finely tuned insulin adjustments and increased carbohydrate intake, vigilance will always be required to maintain some semblance of glycemic control during events of extended duration., (Copyright © 2015 Canadian Diabetes Association. Published by Elsevier Inc. All rights reserved.)

It is relatively well known that moderate-intensity aerobic exercise increases the risk of hypoglycemia in individuals with type 1 diabetes. Conversely, brief high-intensity (anaerobic) activity can cause post-exercise hyperglycemia. Recent evidence has indicated that including small amounts of anaerobic activity, either in the form of short sprints or as resistance exercise (weight lifting), during aerobic exercise sessions may decrease the drop in blood glucose levels associated with moderate-intensity aerobic exercise. This review discusses the recent developments in the area of exercise and type 1 diabetes, with a particular focus on the effects of resistance exercise. Practical exercise recommendations, as well as suggestions for the future direction of research in this area, are also provided., (Copyright © 2013. Published by Elsevier Inc.)