Effect of exercise versus relaxation on haemoglobin A1C in Black females with type 2 diabetes mellitus

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.