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Extended, moderate exercise produced better blood sugar control than several short walks, but the latter may still have a role in diabetes treatment, researchers found.
In a small study, men with type 2 diabetes who performed a single 45-minute moderate exercise routine each day spent less time in hyperglycemia over a 24-hour period than sedentary controls (4 hours and 47 minutes versus 6 hours and 51 minutes, P<0.001), according to Luc J. C. van Loon, PhD, of Maastricht University Medical Center in The Netherlands, and colleagues.
Bursts of activities of daily living (ADL) -- defined in the study as three 15-minute walks meant to reflect light activities such as walking the dog, household tasks, and light gardening -- were also associated with less time spent in hyperglycemia (6 hours and 2 minutes), but not to a significant extent compared with controls (P=0.067), they reported online in Diabetes Care.
"When matched for total duration, a single bout of moderate-intensity endurance-type exercise has a greater impact on daily blood glucose homeostasis than repeated bouts of ADL," van Loon and colleagues wrote. "Nonetheless, the introduction of repeated ADL bouts during prolonged sedentary behavior forms a valuable strategy in the management of type 2 diabetes, especially in those patients who are unable or reluctant to perform structured exercise."
They noted it was "striking" that hyperglycemic episodes occurred despite the fact that most patients were using oral antidiabetic agents and were relatively well controlled based on HbA1c levels -- a finding that highlights the need for additional treatment strategies in type 2 diabetes, they wrote.
Structured exercise is a keystone of treatment for type 2 diabetes, but some work has also suggested that other types of physical activity, including activities of daily living, can aid glucose control.
"Such a low-demanding physical activity strategy would provide an attractive alternative to the application of a more structured exercise regimen, because engaging in and adhering to structured exercise programs have been proven problematic for many patients with type 2 diabetes," the researchers wrote.
To investigate whether a modest increase in activities like those involved in daily living could rival the benefits on glycemic control of more intense exercise, van Loon and colleagues enrolled 20 men with type 2 diabetes in a randomized cross-over study with three experimental periods of 3 days each.
Those conditions involved a sedentary control, three 15-minute periods of walking at a pace to reflect the energy expended in typical activities of daily living, or a single 45-minute session of moderate-intensity exercise.
The researchers used continuous glucose monitoring (CGM) to assess blood sugar levels and took frequent measurements of plasma insulin concentrations.
Overall, they found that the time spent in a hyperglycemic state was significantly lower with exercise. With walking that mimicked activities of daily living, the time in hyperglycemia was attenuated but not significantly reduced, they reported.
There were similar results with average 24-hour blood glucose concentrations; moderate-intensity exercise significantly reduced these levels by 0.6 mmol/L (P<0.001) compared with the sedentary control condition, but average concentrations were basically unchanged with walking, they reported.
Moderate-intensity exercise strongly reduced the glycemic response to breakfast and, to a lesser extent, to lunch and dinner, they found (P<0.05 for all) -- but declines in postprandial glucose concentrations with light activity didn't reach statistical significance.
But, more importantly, the researchers wrote, the cumulative glucose response to all meals as measured by the area under the curve (AUC) was significantly lower during exercise and light activity than among sedentary controls (P<0.001 and P<0.05, respectively).
They also found that postprandial insulin concentrations were significantly lower during exercise and walking than during the sedentary control periods (P<0.001 and P<0.05, respectively).
Although exercise is best, they concluded, the findings confirm the hypothesis that "simply performing activities of daily living can improve postprandial blood glucose homeostasis."
The researchers reported no conflicts of interest.
- Reviewed by F. Perry Wilson, MD, MSCE Instructor of Medicine, Perelman School of Medicine at the University of Pennsylvania and Dorothy Caputo, MA, BSN, RN, Nurse Planner