Effect of exercise versus relaxation on haemoglobin A1c in black females with type 2 diabetes mellitus - Van Rooijen et al. (2004)

Key Points

  • Relaxation reduced HbA1c by 0.97%

  • Participants in the relaxation group reduced HbA1c more than the exercise group (moderate walking was the exercise)

The Breathing Diabetic Summary

This study examined the difference of an exercise program versus a relaxation program in black female subjects with type 2 diabetes.  The interventions occurred over a 12 week period. 

Participants in the relaxation group were taught to progressively tense and then relax different muscle groups for a 20 min period.  They performed this relaxation exercise once every other week.  The exercise participants were asked to walk for 10 min/day at the beginning, gradually increasing this to 45 min/day by the end of the 12 week study.  There were 72 participants in each group for a total of 144.

The main finding of this study was that the exercise group reduced their HbA1c by 0.39% whereas the relaxation group reduced theirs by 0.97%.  These reductions are not earthshattering, but they are significant given that reductions in HbA1c of 0.6% can improve long-term markers of diabetic health.  The relaxation group also significantly reduced their body mass index (BMI).  

The fact that relaxation led to a greater reduction in HbA1c than a walking program is quite surprising.  The authors note that this could be part of the “study effect,” where patients improve simply because they know they are being studied.  However, the authors also note that previous research has shown up to a 0.5% reduction in HbA1c from the practice of relaxation, so it could be more than just “coincidence” that relaxation improved HbA1c more than walking.

For us, we know that diabetics spend more time in a sympathetic, fight-or-flight mode.  Thus, relaxation of any kind (even if a breathing protocol is not involved) is likely to help increase parasympathetic tone and improve blood sugars.  But, we can do even better by adding in the benefits of light and slow breathing (e.g., better tissue oxygenation, higher BRS, etc.) to maximize the positive impacts of relaxation.

Abstract from Paper

Background: Evidence suggests that populations in Africa develop Type 2 diabetes mellitus (DM) at an increasing rate as they reject their traditional lifestyles. Diabetes is the tenth most common cause for total life years lost in females in South Africa. Physical activity is under-used in the management of type 2 DM in South Africa.

Aim: To investigate the efficacy of an exercise intervention programme compared to relaxation exercises to decrease HbA1c over a period of 12 weeks, in type 2 DM female subjects.

Design: Single blind, double-intervention randomized trial.

Methods: Clinical measurements were done before and after the 12-week exercise and relaxation interventions. The interventions consisted of education and aerobic exercise for the exercise group, and education and relaxation for the second group.

Results: Adjusted baseline HbA1c change from baseline in the exercise group after 12 weeks was −0.39% (95%CI −0.80 to 0.02) and in the relaxation group −0.97% (95%CI −1.38 to 0.55) (p = 0.052). The results for the BMI were −0.07% kg/m2 (95%CI −0.2 to 0.14) in the exercise group versus −0.23 kg/m2 (95%CI −0.44 to 0.02) in the relaxation group (p = 0.28). The difference from baseline in distances covered following the 6 min walk test was statistically significantly greater (p < 0.01) in the exercise group: 46.76 m (95%CI 36.20–57.32) vs the relaxation group 22.7 m (95%CI 12.07–33.33).

Discussion: The exercise intervention failed to reduce the HbA1c to a greater extent than in the relaxation control group. Both groups improved significantly from baseline, probably due to the study effect.

Journal Reference:

A.J. Van Rooijen, P. Rheeder, C.J. Eales, and P.J. Becker, (2004) Effect of exercise versus relaxation on haemoglobin A1c in black females with type 2 diabetes mellitus, Q J Med, 97, 343 – 351.