Afternoon a better time to exercise for glucose control in T2D

Exercising late in the afternoon may be more potent than working out at any other time of the day for lowering blood sugar levels in people with overweight or obesity and type 2 diabetes (T2D), as reported in a study.

For the study, researchers used data from the Look AHEAD study and examined the effect of time-of-day of bout-related moderate-to-vigorous physical activity (bMVPA) on changes in glycaemic control across 4 years. A total of 2,416 individuals (mean age 59 years, 57 percent women) with overweight/obesity and T2D comprised the study population.

At years 1 and 4, the participants wore a waist accelerometer for 7 days to measure physical activity. The resulting data were used to determine the time of the day the participants engaged in bMVPA. The time-varying exposure of bMVPA (≥10-min bout) timing was defined as ≥50 percent of bMVPA occurring during the same time period (morning, midday, afternoon, or evening), <50 percent of bMVPA in any time period (mixed), and ≤1 day with bMVPA per week (inactive).

At 1 year, the observed reductions in HbA1c differed among bMVPA timing groups (p=0.02), regardless of weekly bMVPA volume and intensity.

Notably, participants who engaged in bMVPA in the afternoon had the greatest HbA1c reduction compared with those who were inactive (−0.22 percent, 95 percent confidence interval [CI], −0.39 percent to −0.06 percent). The magnitude of glucose lowering in the afternoon group was 30–50 percent greater than in the other groups.

The odds of discontinuing vs maintaining or initiating glucose-lowering medications at year 1 varied by bMVPA timing as well (p=0.04), with the afternoon group having the highest odds (odds ratio, 2.13, 95 percent CI, 1.29–3.52).

No significant changes in HbA1c between year 1 and 4 across all the bMVPA timing groups.