Effect of moderate-intensity exercise versus activities of daily living on 24-hour blood glucose homeostasis in male patients with type 2 diabetes

Abstract

Objective: To investigate the impact of activities of daily living (ADL) versus moderate-intensity endurance-type exercise on 24-h glycemic control in patients with type 2 diabetes.

Research design and methods: Twenty males with type 2 diabetes participated in a randomized crossover study consisting of three experimental periods of 3 days each. Subjects were studied under sedentary control conditions, and under conditions in which prolonged sedentary time was reduced either by three 15-min bouts of ADL (postmeal strolling, ∼3 METs) or by a single 45-min bout of moderate-intensity endurance-type exercise (∼6 METs). Blood glucose concentrations were assessed by continuous glucose monitoring, and plasma insulin concentrations were determined in frequently sampled venous blood samples.

Results: Hyperglycemia (glucose >10 mmol/L) was experienced for 6 h 51 min ±1 h 4 min per day during the sedentary control condition and was significantly reduced by exercise (4 h 47 min ± 1 h 2 min; P < 0.001), but not by ADL (6 h 2 min ± 1 h 16 min; P = 0.67). The cumulative glucose incremental areas under the curve (AUCs) of breakfast, lunch, and dinner were, respectively, 35 ± 5% (P < 0.001) and 17 ± 6% (P < 0.05) lower during the exercise and ADL conditions compared with the sedentary condition. The insulin incremental AUCs were, respectively, 33 ± 4% (P < 0.001) and 17 ± 5% (P < 0.05) lower during the exercise and ADL conditions compared with the sedentary condition.

Conclusions: When matched for total duration, moderate-intensity endurance-type exercise represents a more effective strategy to improve daily blood glucose homeostasis than repeated bouts of ADL. Nevertheless, the introduction of repeated bouts of ADL during prolonged sedentary behavior forms a valuable strategy to improve postprandial glucose handling in patients with type 2 diabetes.

Trial registration: ClinicalTrials.gov NCT00945165.

Figures

Figure 1

The 24-h glycemic profiles in type 2 diabetic patients under sedentary conditions and under conditions in which prolonged sedentary time was reduced by three 15-min bouts of activities of daily living (ADL; gray squares) or by a single 45-min bout of moderate-intensity endurance-type exercise (checkered square). The dotted lines indicate the ingestion of the main meals (0830, 1230, and 1700 h) or snack (2030 h). The error bars are not shown for clarity.

Figure 2

The impact of the three experimental conditions on the prevalence of hyperglycemia over the course of 24 h (A), average 24-h blood glucose concentrations (B), and the cumulative postprandial glucose iAUC (C). Data represent mean ± SEM. *Significantly lower compared with the sedentary condition (P < 0.05). †Significantly lower compared with ADL condition (P < 0.05).

Figure 3

The impact of the three experimental conditions on insulin concentrations over time (A) and the postprandial insulin iAUC (B). Data represent mean ± SEM. aDifference between sedentary and ADL conditions (P < 0.05). bDifference between sedentary and exercise conditions (P < 0.05). cDifference between ADL and exercise conditions. *Significantly lower compared with sedentary condition (P < 0.05). †Significantly lower compared with ADL (P < 0.001).