Regular physical activity is a cornerstone of diabetes management. We conducted a study to evaluate whether specifying the timing of walking in relation to meals enhances the benefits conferred by current physical activity guidelines.
A total of 41 adults with type 2 diabetes mellitus (mean ± SD age 60 ± 9.9 years; mean diabetes duration 10 years) participated in this randomised, crossover study. Randomisation was by a computer-generated protocol. For periods of 2 weeks, advice to walk 30 min each day was compared with advice to walk for 10 min after each main meal. Both sets of advice met current physical activity guidelines for people with type 2 diabetes mellitus. Physical activity was measured by accelerometry over the full intervention, and glycaemia was measured using continuous glucose monitoring in 5 min intervals over 7 days. The primary outcome of postprandial glycaemia was assessed during the 3 h after a meal by the incremental area under the blood glucose curve (iAUC).
The iAUC was significantly lower when participants walked after meals compared with on a single daily occasion (ratio of geometric means 0.88, 95% CI 0.78, 0.99). The improvement was particularly striking after the evening meal (0.78, 95% CI 0.67, 0.91) when the most carbohydrate was consumed and sedentary behaviours were highest. One participant died during the 30 day washout period between interventions, but participation in this study was not judged to contribute to this unfortunate event.
The benefits relating to physical activity following meals suggest that current guidelines should be amended to specify post-meal activity, particularly when meals contain a substantial amount of carbohydrate.