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Effect of Leisure-time Physical Activity on HbA1c in Type 2 Diabetes

Are some leisure-time activities more helpful than others in lowering blood glucose?

As we know, recommended therapy for type 2 diabetes patients includes regular physical activity, adherence to medications and a disciplined diet. We also know from previous studies that physical activity lowers plasma glucose levels in the short-term and HbA1c in the long-term. The World Health Organization (WHO) recommends 150 minutes of moderate intensity physical exercise weekly. It has been found that participation in leisure-time physical activity, in addition to housework and physical activities at work, contributes to better glycemic control in people with type 2 diabetes. However, studies to date have primarily focused on individual leisure activities, or included control groups with no standard of care. There has not been a study to compare effectiveness between leisure activities until now.

For the current meta-analysis, a composite of Chinese and English language databases were searched between the years 1960 to 2014 for keywords pertaining to glycemic control and leisure-time physical activities in people with type 2 diabetes. The primary outcome was the difference in HbA1c levels of participants at baseline and 8 weeks later in type 2 diabetes patients. This was designed as a 2-arm study with the intervention group receiving “routine care,” including medication, dietary control and physical activities with the addition of leisure-time physical activity. The control group received routine care as defined above without the addition of leisure-time physical activity. In order to be included in the intervention group, the participants had to perform leisure-time physical activity for at least 8 consecutive weeks, 2-3 times per week for a duration of at least 30 minutes per session.

The impact of each treatment was measured using the difference in mean and standard deviation of HbA1c in participants before and after the intervention in the experimental, as well as the control group. The standard mean difference (SMD) and 95% confidence intervals were used to summarize the statistics for overall size of effect. To evaluate the impact of different types of leisure-time physical activity on HbA1c, subgroup analysis was also conducted.

Initially 2,912 articles were identified through the keyword searches of the 10 databases. After reviewing for inclusion and exclusion criteria, 18 articles were included in the systemic review with low risk of bias. Participants ranged between the ages of 35 to 71 years old and were 65% female. Of the selected studies, the leisure-time physical activities analyzed were walking, yoga and tai chi. It was found that yoga was the most effective intervention in lowering HbA1c: SMD: -0.81, CI: -0.35 to -1.22. This was followed by tai chi: SMD: -0.75, CI: -0.35 to -1.15 and walking: SMD: -0.56, CI: -0.20 to -0.92. Participants partaking in leisure-time physical activity with higher frequency experienced more effective reduction in HbA1c levels. The effect of HbA1c reduction in the experimental group was greater than in the control group: SMD: -0.60, CI: -0.37 to -0.83.

Yoga incorporates calorie-burning movement and breathing. The fact that, of the activities studied, yoga and tai chi had the greatest lowering effect of leisure-time physical activity on HbA1c may not be surprising, as this information corroborates other studies supporting the benefit of aerobic activities in people with type 2 diabetes. Though the difference between the experimental and control groups were calculated in this analysis, many of the studies included did not provide a comparison between before and after HbA1c values between the two groups. This could be improved upon in future analysis; as could a clear definition of what constitutes “general physical activities” in the control group. Furthermore, this analysis only included Chinese and English articles, which may have failed to capture leisure-time physical activities of other cultures that may be superior at lowering HbA1c in type 2 patients. Despite the limitations of this study, it did accomplish its primary outcome to quantify the positive effects of individual leisure-time physical activities.

Practice Pearls:

  • Leisure-time physical activity should be incorporated into most if not all type 2 diabetes therapeutic regimens.
  • Yoga and tai chi have the greatest HbA1c lowering effect of analyzed leisure-time physical activity.
  • For greatest benefit of leisure-time physical activity, it should be done for at least 150 minutes per week and for greater than 8 weeks duration.

Researched and prepared by Devon Brooks, Doctor of Pharmacy Candidate from LECOM College of Pharmacy, reviewed by Dave Joffe, BSPharm, CDE
Pai LW, Li TC, Hwu YJ, Et al. “The effectiveness of regular leisure-time physical activities on long-term glycemic control in people with type 2 diabetes: A systemic review and meta-analysis.” Diabetes Research and Clinical Practice. (2016) 113:77-85.