J David Taylor1, James P Fletcher2, Ruth Ann Mathis3, W Todd Cade4. 1. J.D. Taylor, PT, PhD, CSCS, Department of Physical Therapy, University of Central Arkansas, 201 Donaghey Ave, Physical Therapy Center, Room 319, Conway, AR 72035 (USA). dtaylor@uca.edu. 2. J.P. Fletcher, PT, PhD, ATC, Department of Physical Therapy, University of Central Arkansas. 3. R.A. Mathis, PT, PhD, Physical Therapy Program, Harding University, Searcy, Arkansas. 4. W.T. Cade, PT, PhD, Program in Physical Therapy, Washington University, St Louis, Missouri.
Abstract
BACKGROUND:Exercise training is effective for improving physical fitness and physical function in people with type 2 diabetes. However, limited research has been conducted on the optimal exercise training intensity for this population. OBJECTIVE: The primary study objective was to investigate the effects of moderate- versus high-intensity exercise training on physical fitness and physical function in people with type 2 diabetes. DESIGN: This was a randomized clinical trial. SETTING: The setting was a university campus. PARTICIPANTS: Twenty-one people with type 2 diabetes were randomly allocated to receive either moderate-intensity training (MOD group) or high-intensity training (HIGH group). INTERVENTION: The MOD group performed resistance training at an intensity of 75% of the 8-repetition maximum (8-RM) and aerobic training at an intensity of 30% to 45% of the heart rate reserve (HRR). The HIGH group performed resistance training at an intensity of 100% of the 8-RM and aerobic training at an intensity of 50% to 65% of the HRR. MEASUREMENTS: Muscle strength (peak torque [newton-meters]), exercise capacity (graded exercise test duration [minutes]), and physical function (Patient-Specific Functional Scale questionnaire) were measured at baseline and 3 months later. Acute exercise-induced changes in glucose levels were assessed immediately before exercise, immediately after exercise, and 1 hour after exercise during the first exercise training session. RESULTS: Although both groups showed improvements in physical fitness and physical function, the between-group effect sizes were not statistically significant (exercise capacity estimated marginal mean [EMM] difference=2.1, 95% confidence interval [95% CI]=-0.2, 4.5; muscle strength EMM difference=20.8, 95% CI=-23.3, 65.0; and physical function EMM difference=0.1, 95% CI=-0.6, 0.9). Mean percent changes in glucose levels measured immediately before exercise and immediately after exercise, immediately after exercise and 1 hour after exercise, and immediately before exercise and 1 hour after exercise for the MOD group were -11.4%, -5.0%, and -15.8%, respectively; those for the HIGH group were -21.5%, 7.9%, and -15.3%, respectively. LIMITATIONS: Sample size, lack of outcome assessor masking, and physical function measurement subjectivity were limitations. CONCLUSIONS:Moderate- and high-intensity exercise training, as defined in this study, may lead to similar improvements in physical fitness and physical function in people with type 2 diabetes.
RCT Entities:
BACKGROUND: Exercise training is effective for improving physical fitness and physical function in people with type 2 diabetes. However, limited research has been conducted on the optimal exercise training intensity for this population. OBJECTIVE: The primary study objective was to investigate the effects of moderate- versus high-intensity exercise training on physical fitness and physical function in people with type 2 diabetes. DESIGN: This was a randomized clinical trial. SETTING: The setting was a university campus. PARTICIPANTS: Twenty-one people with type 2 diabetes were randomly allocated to receive either moderate-intensity training (MOD group) or high-intensity training (HIGH group). INTERVENTION: The MOD group performed resistance training at an intensity of 75% of the 8-repetition maximum (8-RM) and aerobic training at an intensity of 30% to 45% of the heart rate reserve (HRR). The HIGH group performed resistance training at an intensity of 100% of the 8-RM and aerobic training at an intensity of 50% to 65% of the HRR. MEASUREMENTS: Muscle strength (peak torque [newton-meters]), exercise capacity (graded exercise test duration [minutes]), and physical function (Patient-Specific Functional Scale questionnaire) were measured at baseline and 3 months later. Acute exercise-induced changes in glucose levels were assessed immediately before exercise, immediately after exercise, and 1 hour after exercise during the first exercise training session. RESULTS: Although both groups showed improvements in physical fitness and physical function, the between-group effect sizes were not statistically significant (exercise capacity estimated marginal mean [EMM] difference=2.1, 95% confidence interval [95% CI]=-0.2, 4.5; muscle strength EMM difference=20.8, 95% CI=-23.3, 65.0; and physical function EMM difference=0.1, 95% CI=-0.6, 0.9). Mean percent changes in glucose levels measured immediately before exercise and immediately after exercise, immediately after exercise and 1 hour after exercise, and immediately before exercise and 1 hour after exercise for the MOD group were -11.4%, -5.0%, and -15.8%, respectively; those for the HIGH group were -21.5%, 7.9%, and -15.3%, respectively. LIMITATIONS: Sample size, lack of outcome assessor masking, and physical function measurement subjectivity were limitations. CONCLUSIONS: Moderate- and high-intensity exercise training, as defined in this study, may lead to similar improvements in physical fitness and physical function in people with type 2 diabetes.