Effect of a single vs multiple bouts of exercise on glucose control in women with type 2 diabetes.
ABSTRACT The Surgeon General and Centers for Disease Control and Prevention have recommended that multiple bouts of exercise can be accumulated throughout the day in lieu of the more traditional single, longer bout of exercise. Yet, conclusive evidence does not exist suggesting these 2 training modes provide similar health-related benefits on metabolic control, especially in individuals with type 2 diabetes. The purpose of this study was to determine if differences exist in glucose control when preceded by one 30-minute or three 10-minute bouts of exercise in women with type 2 diabetes. Nine individuals with type 2 diabetes (53 +/- 6 years old) and 6 control women (49 +/- 4 years old) completed 3 randomly ordered oral glucose tolerance tests (OGTTs). Two of the OGTTs were preceded the day prior by moderate exercise (approximately 60% of Vo2peak), either one 30-minute or three 10-minute bouts, whereas the third OGTT was used as a control day with no exercise performed 3 days prior. Glucose and insulin were measured every 30 minutes for 4 hours during the OGTT. Individuals with type 2 diabetes exhibited a greater overall glucose response than the controls (P < .05), but the glucose response to the OGTT was not different between the 3 conditions within each group (2-hour glucose: multiple bout, 14.3 +/- 3.2 vs 5.0 +/- 1.7; single bout, 14.1 +/- 3.0 vs 4.7 +/- 1.5; control day, 14.6 +/- 2.7 vs 4.9 +/- 4.9 mmol/L). Glucose area under the curve analysis resulted in similar findings. As expected, the group with type 2 diabetes had greater fasting insulin levels compared with the control group for all exercise conditions (multiple bout: 4.5 +/- 1.2 vs 0.3 +/- 0.2; single bout: 6.4 +/- 1.6 vs 0.9 +/- 0.4; control day: 5.7 +/- 1.8 vs 1.5 +/- 0.6 pmol/L; P < .05). Exercise or no exercise did not alter the insulin response to the OGTT for either group. Despite a higher glucose response to the glucose load in T2D, an acute exercise bout (single or multiple bouts) did not appear to alter glucose control the following day in either the individuals with type 2 diabetes or the control group.
- SourceAvailable from: Michael E. Holmstrup[Show abstract] [Hide abstract]
ABSTRACT: The purpose of this study was (1) to determine if overweight/obese individuals (age 26-50 y) would self-select moderate exercise intensity when asked to do so and (2) to determine how this self-selected workload compared to exercising at a workload (60% peak aerobic capacity) that is known to provide cardioprotective health benefits. Oxygen consumption (VO(2)) and energy expenditure were measured in 33 men/women (BMI ≥ 27 kg/m(2)) who completed two 30 min walking bouts: (1) self-selected walking pace on an indoor track and (2) prescribed exercise pace (60% VO(2) peak) on a treadmill. The data revealed that (1) the prescribed intensity was 6% higher than the self-selected pace and elicited a higher energy expenditure (P < 0.05) than the self-selected pace (+83 kJ); (2) overweight subjects walked at a slightly lower percentage of VO(2) peak than the obese subjects (P < 0.05); (3) men walked at a lower percentage of VO(2) peak than the women (P < 0.05). In conclusion when asked to walk at a moderate intensity, overweight/obese individuals tended to select a lower workload in the "moderate intensity" range which could be maintained for 30 min; however, a higher intensity which would be more cardioprotective could not be maintained for 30 min by most individuals.Journal of obesity 05/2012; 2012:919051. DOI:10.1155/2012/919051
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ABSTRACT: Hypoxia and muscle contraction stimulate glucose transport in vitro. We have previously demonstrated that exercise and hypoxia have an additive effect on insulin sensitivity in type 2 diabetics. Our objective was to examine the effects of three different hypoxic/exercise (Hy Ex) trials on glucose metabolism and insulin resistance in the 48 h after acute hypoxia in type 2 diabetics. DESIGN, PARTICIPANTS, AND INTERVENTIONS: Eight male type 2 diabetics completed 60 min of hypoxic [mean (sem) O(2) = ∼14.7 (0.2)%] exercise at 90% of lactate threshold [Hy Ex(60); 49 (1) W]. Patients completed an additional two hypoxic trials of equal work, lasting 40 min [Hy Ex(40); 70 (1) W] and 20 min [Hy Ex(20); 140 (12) W]. Glucose rate of appearance and rate of disappearance were determined using the one-compartment minimal model. Homeostasis models of insulin resistance (HOMA(IR)), fasting insulin resistance index and β-cell function (HOMA(β-cell)) were calculated at 24 and 48 h after trials. Peak glucose rate of appearance was highest during Hy Ex(20) [8.89 (0.56) mg/kg · min, P < 0.05]. HOMA(IR) and fasting insulin resistance index were improved in the 24 and 48 h after Hy Ex(60) and Hy Ex(40) (P < 0.05). HOMA(IR) decreased 24 h after Hy Ex(20) (P < 0.05) and returned to baseline values at 48 h. Moderate-intensity exercise in hypoxia (Hy Ex(60) and Hy Ex(40)) stimulates acute- and moderate-term improvements in insulin sensitivity that were less apparent in Hy Ex(20). Results suggest that exercise duration and not total work completed has a greater influence on acute and moderate-term glucose control in type 2 diabetics.The Journal of Clinical Endocrinology and Metabolism 01/2012; 97(1):155-62. DOI:10.1210/jc.2011-1843 · 6.31 Impact Factor
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ABSTRACT: Hypoxia and muscle contraction stimulate glucose transport activity in vitro. Exercise and hypoxia have additive effects on insulin sensitivity in type 2 diabetics (T2D). The objective of the study was to examine the effectiveness of intermittent exercise with and without hypoxia on acute- and moderate-term glucose kinetics and insulin sensitivity in T2D. The study was conducted at a university research center. DESIGN, PARTICIPANTS, AND INTERVENTIONS: Eight male T2D patients completed the following: 1) 60 min of continuous exercise at 90% lactate threshold in hypoxia (HyEx60); 2) intermittent exercise at 120% lactate threshold, separated by periods of passive recovery (5:5 min) in hypoxia [Hy5:5; O₂ ∼ 14.7 (0.2)%]; and 3) intermittent exercise (5:5 min) at 120% lactate threshold in normoxia (O₂ ∼ 20.93%). Glucose appearance and glucose disappearance, using an adapted non-steady-state one-compartment model were measured. Homeostasis models of insulin resistance (HOMA(IR)), fasting insulin resistance index (FIRI), and β-cell function were calculated 24 and 48 h after exercise conditions. Glucose disappearance increased from baseline (1.85 mg/kg · min⁻¹) compared with 24 h (2.01 min/kg · min⁻¹) after HyEx60 (P = 0.031). No difference was noted for both Hy5:5 (P = 0.064) and normoxia (P = 0.385). Hy5:5 demonstrated improvements in HOMA(IR) from baseline [d 1, 6.20 (0.40)] when comparisons were made with d 2 [4.83 (0.41)] (P = 0.0013). HOMA(IR) and FIRI improved in the 24 h (HOMA(IR), P = 0.002; FIRI, P = 0.003), remaining reduced 48 h after HyEx60 (HOMA(IR), P = 0.028; and FIRI, P = 0.034). HyEx60 offered the greatest improvements in acute and moderate-term glucose control in T2D. Intermittent exercise stimulated glucose disposal and improved post-exercise insulin resistance, which was enhanced when exercise was combined with hypoxia (Hy5:5). The data suggest a use of hypoxic exercise in treatment of T2D.The Journal of Clinical Endocrinology and Metabolism 01/2012; 97(4):E546-55. DOI:10.1210/jc.2011-2829 · 6.31 Impact Factor