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Physical Activity Intensity and Risk Factors for Type 2 Diabetes in Obese Youth: The POWER Trial
Abstracts / Can J Diabetes 37 (2013) S13eS84
Purpose: To determine the proportion of participants exercising regularly 8 to 12 years after completion of a 6-month exercise trial, and to explore behavioural factors affecting exercise maintenance and willingness to perform lower versus higher volumes of resistance exercise. Methods: Telephone interviews were conducted using a validated questionnaire to assess current exercise participation and openended questions to explore exercise preferences. Results: Eighty-four participants (33% of original cohort) were interviewed (median age 68 years, 63% male). Thirty-four participants (41%) reported exercising regularly (at least 30 minutes of moderate intensity physical activity 3 or more days per week): 32 (38%) reported regular moderate or strenuous aerobic exercise, and 21 (25%) regular resistance exercise. Nineteen (23%) reported barriers to exercise due to physical limitations or medical issues. Although 56 (66%) had maintained or increased motivation to exercise, only 28 (33%) maintained or increased their exercise since completion of the DARE trial. Participants expressed greater willingness to perform resistance training 20 minutes twice per week compared to 45 minutes 3 times per week. Conclusion: Among this group of previously sedentary T2DM adults, 41% still exercised regularly 8 to 12 years after completion of a 6-month exercise intervention. Fewer performed resistance exercise than aerobic exercise. Barriers to exercise included physical limitations and perceived lack of access to exercise programs. Further analysis of our original 251 participant cohort is ongoing.
S51
140 Effects of Sport-Specific, Intermittent High-Intensity Exercise on Post-Exercise Heart Rate Variability and Glycemia in Young Athletes with Type 1 Diabetes LISA A. MIADOVNIK*, MICHAEL C. RIDDELL, ROBERT J. GUMIENIAK, CHIP P. ROWEN, DESSI P. ZAHARIEVA, VERONICA K. JAMNIK Toronto, ON
139
Type 1 diabetes (T1D) is associated with hypoglycemia and premature autonomic disturbance (using heart rate variability [HRV])eboth of which have been implicated in sudden death. Chronic exercise improves HRV in individuals with T1D; however, the acute effects of a single bout of exercise on subsequent nocturnal HRV remain unknown. We recruited hockey players with and without T1D in order to examine how a single bout of intermittent high-intensity exercise (IHE) impacts nocturnal HRV. HRV was analyzed from 12 am to 6 am following 3 events; a hockey game, an IHE bout on a cycle ergometer and a non-exercise day. Continuous glucose monitors recorded blood glucose (BG). Lab exercise led to a mean BG decrease of 2.33 mmol/L, while the change during a hockey game was insignificant (mean D: e0.24.2 mmol/L). There was 1 incidence of nocturnal hypoglycemia, which occurred after a hockey game (lasting 225 min). No significant differences in HRV were noted between nights, with a trend toward improved HRV after the non-exercise day in all participants. More favourable HRV profiles (higher SDNN, RMSSD, HF and TP) were observed in T1D participants across all nights (p>0.05). SDNN, used as an estimate of overall HRV, was 50% greater for those with T1D (p<0.05), but only after the non-exercise day. Given that a decrease in SDNN has been associated with sudden cardiac death, this increase in SDNN may have a protective benefit in individuals with T1D.
Physical Activity Intensity and Risk Factors for Type 2 Diabetes in Obese Youth: The POWER Trial ANDREA C. MACINTOSH*, KRISTY D.M. WITTMEIER, JACQUELINE L. HAY, LORI BERARD, JONATHAN M. MCGAVOCK Winnipeg, MB
141
Study Hypothesis: We conducted a randomized controlled trial to test the hypothesis that compared to controls, vigorous-intensity physical activity (PA) would lead to a greater reduction in hepatic triglyceride content (HTC) and improvement in insulin sensitivity than moderate-intensity PA, despite similar caloric expenditure. Methods: Following a 2-week run-in phase, overweight youth 13 to 19 years with 1 risk factor for type 2 diabetes were randomized to either PA at >70% of peak fitness (VPA), PA at 40% to 55% of peak fitness (MPA) or control. PA was delivered 3 times weekly for 30 to 45 minutes for 6 months. The outcomes of the study were IVGTT-derived insulin sensitivity and MRS-derived HTC. Results: One hundred and twenty obese youth (BMI Z score ¼ 2.10.4) were randomized to VPA (n¼48); control (n¼36) or MPA (n¼36). No statistically significant differences were observed between the groups for either outcome, however HTC was reduced in VPA (e0.05; 95% CI: e0.3 to +0.2 fat/water%) but not in MPA (0.04; 95% CI: e0.3 to +0.3 fat/water%) compared to control (+0.22; 95% CI: e0.1 to +0.5 fat/water%). VPA (+1.3; 95% CI: 0.4 to 2.2 mL/kg/min) and MPA (+1.1; 95% CI: 0.1 to 2.2 mL/ kg/min) experienced significantly greater improvements in cardiorespiratory fitness compared to control (e0.6; 95% CI: e1.6 to +0.4 mL/kg/min). Conclusion: Increased PA, regardless of intensity, leads to clinically meaningful improvements in fitness in obese youth. VPA was associated with a modest trend toward reductions in hepatic triglyceride compared to either moderate intensity PA or control.
Dual-Task Walking Performance of Older Adults with Diabetes Mellitus: Effects of Time Constraints PATRICIA A. HEWSTON*, ETIENNE J. BISSON, NANDINI DESHPANDE Kingston, ON Introduction: Pro-oxidative effects of type 2 diabetes mellitus (T2DM) have been shown to impair cognitive function and may led to difficulty in performing mobility tasks with additional challenges that are often encountered in daily life. The purpose of this ongoing study is to understand the effect of time constraints on dual-task walking performance of older adults with T2DM. Methods: Fifteen older adults 65+ years of age were recruited into 2 groups: 7 with T2DM and 8 healthy controls (HC). Participants walked along a 6 m path at their comfortable selfselected or fastest pace. Dual tasks involved either a cognitive (serial subtraction by 1’s or 3’s) or motor (carrying a basket) task. Preliminary outcome measures of walking performance included total time to complete the walking task and cognitive performance. Results: Older adults with T2DM required more time to walk the path than HC (p<0.05). Total time decreased 22% in the fastest pace compared to the self-selected pace conditions in both T2DM and HC (p<0.001). Total time increased with both cognitive tasks (p<0.05), however, was not influenced with the motor task (p>0.05). No difference between groups was found in cognitive performance (p>0.05). Discussion: Older adults with T2DM walked slower than HC which is a known cautious strategy to maintain balance. However, when challenged with time constraints or a dual task, older adults with
Purpose: To determine the proportion of participants exercising regularly 8 to 12 years after completion of a 6-month exercise trial, and to explore behavioural factors affecting exercise maintenance and willingness to perform lower versus higher volumes of resistance exercise. Methods: Telephone interviews were conducted using a validated questionnaire to assess current exercise participation and openended questions to explore exercise preferences. Results: Eighty-four participants (33% of original cohort) were interviewed (median age 68 years, 63% male). Thirty-four participants (41%) reported exercising regularly (at least 30 minutes of moderate intensity physical activity 3 or more days per week): 32 (38%) reported regular moderate or strenuous aerobic exercise, and 21 (25%) regular resistance exercise. Nineteen (23%) reported barriers to exercise due to physical limitations or medical issues. Although 56 (66%) had maintained or increased motivation to exercise, only 28 (33%) maintained or increased their exercise since completion of the DARE trial. Participants expressed greater willingness to perform resistance training 20 minutes twice per week compared to 45 minutes 3 times per week. Conclusion: Among this group of previously sedentary T2DM adults, 41% still exercised regularly 8 to 12 years after completion of a 6-month exercise intervention. Fewer performed resistance exercise than aerobic exercise. Barriers to exercise included physical limitations and perceived lack of access to exercise programs. Further analysis of our original 251 participant cohort is ongoing.
S51
140 Effects of Sport-Specific, Intermittent High-Intensity Exercise on Post-Exercise Heart Rate Variability and Glycemia in Young Athletes with Type 1 Diabetes LISA A. MIADOVNIK*, MICHAEL C. RIDDELL, ROBERT J. GUMIENIAK, CHIP P. ROWEN, DESSI P. ZAHARIEVA, VERONICA K. JAMNIK Toronto, ON
139
Type 1 diabetes (T1D) is associated with hypoglycemia and premature autonomic disturbance (using heart rate variability [HRV])eboth of which have been implicated in sudden death. Chronic exercise improves HRV in individuals with T1D; however, the acute effects of a single bout of exercise on subsequent nocturnal HRV remain unknown. We recruited hockey players with and without T1D in order to examine how a single bout of intermittent high-intensity exercise (IHE) impacts nocturnal HRV. HRV was analyzed from 12 am to 6 am following 3 events; a hockey game, an IHE bout on a cycle ergometer and a non-exercise day. Continuous glucose monitors recorded blood glucose (BG). Lab exercise led to a mean BG decrease of 2.33 mmol/L, while the change during a hockey game was insignificant (mean D: e0.24.2 mmol/L). There was 1 incidence of nocturnal hypoglycemia, which occurred after a hockey game (lasting 225 min). No significant differences in HRV were noted between nights, with a trend toward improved HRV after the non-exercise day in all participants. More favourable HRV profiles (higher SDNN, RMSSD, HF and TP) were observed in T1D participants across all nights (p>0.05). SDNN, used as an estimate of overall HRV, was 50% greater for those with T1D (p<0.05), but only after the non-exercise day. Given that a decrease in SDNN has been associated with sudden cardiac death, this increase in SDNN may have a protective benefit in individuals with T1D.
Physical Activity Intensity and Risk Factors for Type 2 Diabetes in Obese Youth: The POWER Trial ANDREA C. MACINTOSH*, KRISTY D.M. WITTMEIER, JACQUELINE L. HAY, LORI BERARD, JONATHAN M. MCGAVOCK Winnipeg, MB
141
Study Hypothesis: We conducted a randomized controlled trial to test the hypothesis that compared to controls, vigorous-intensity physical activity (PA) would lead to a greater reduction in hepatic triglyceride content (HTC) and improvement in insulin sensitivity than moderate-intensity PA, despite similar caloric expenditure. Methods: Following a 2-week run-in phase, overweight youth 13 to 19 years with 1 risk factor for type 2 diabetes were randomized to either PA at >70% of peak fitness (VPA), PA at 40% to 55% of peak fitness (MPA) or control. PA was delivered 3 times weekly for 30 to 45 minutes for 6 months. The outcomes of the study were IVGTT-derived insulin sensitivity and MRS-derived HTC. Results: One hundred and twenty obese youth (BMI Z score ¼ 2.10.4) were randomized to VPA (n¼48); control (n¼36) or MPA (n¼36). No statistically significant differences were observed between the groups for either outcome, however HTC was reduced in VPA (e0.05; 95% CI: e0.3 to +0.2 fat/water%) but not in MPA (0.04; 95% CI: e0.3 to +0.3 fat/water%) compared to control (+0.22; 95% CI: e0.1 to +0.5 fat/water%). VPA (+1.3; 95% CI: 0.4 to 2.2 mL/kg/min) and MPA (+1.1; 95% CI: 0.1 to 2.2 mL/ kg/min) experienced significantly greater improvements in cardiorespiratory fitness compared to control (e0.6; 95% CI: e1.6 to +0.4 mL/kg/min). Conclusion: Increased PA, regardless of intensity, leads to clinically meaningful improvements in fitness in obese youth. VPA was associated with a modest trend toward reductions in hepatic triglyceride compared to either moderate intensity PA or control.
Dual-Task Walking Performance of Older Adults with Diabetes Mellitus: Effects of Time Constraints PATRICIA A. HEWSTON*, ETIENNE J. BISSON, NANDINI DESHPANDE Kingston, ON Introduction: Pro-oxidative effects of type 2 diabetes mellitus (T2DM) have been shown to impair cognitive function and may led to difficulty in performing mobility tasks with additional challenges that are often encountered in daily life. The purpose of this ongoing study is to understand the effect of time constraints on dual-task walking performance of older adults with T2DM. Methods: Fifteen older adults 65+ years of age were recruited into 2 groups: 7 with T2DM and 8 healthy controls (HC). Participants walked along a 6 m path at their comfortable selfselected or fastest pace. Dual tasks involved either a cognitive (serial subtraction by 1’s or 3’s) or motor (carrying a basket) task. Preliminary outcome measures of walking performance included total time to complete the walking task and cognitive performance. Results: Older adults with T2DM required more time to walk the path than HC (p<0.05). Total time decreased 22% in the fastest pace compared to the self-selected pace conditions in both T2DM and HC (p<0.001). Total time increased with both cognitive tasks (p<0.05), however, was not influenced with the motor task (p>0.05). No difference between groups was found in cognitive performance (p>0.05). Discussion: Older adults with T2DM walked slower than HC which is a known cautious strategy to maintain balance. However, when challenged with time constraints or a dual task, older adults with