Effects of morning versus evening exercise on vascular function in older adults with type 2 diabetes: a randomised controlled trial

Cardiovascular disease is a common complication of type 2 diabetes mellitus (T2DM), with increased risk closely associated with vascular dysfunction. Exercise is an effective strategy for improving vascular health, but whether exercise timing influences long-term vascular adaptations in patients with T2DM remains unclear. In this study, we investigated the effects of morning versus evening exercise on vascular function in older adults with T2DM.

Sixty-six older adults with T2DM were randomised to morning exercise, evening exercise, or control (n = 22 each). The exercise groups received 12 weeks of online moderate-intensity aerobic and resistance exercises, three times per week. The morning group exercised from 9:00 to 10:10, and the evening group from 19:00 to 20:10. The control group maintained their usual lifestyle and attended weekly health education sessions without structured exercise. Blood pressure, brachial-ankle pulse wave velocity (baPWV), flow-mediated vasodilation (FMD) and plasma nitric oxide (NO) levels were assessed at baseline and post-intervention. Outcomes were analysed using two-way repeated-measures analysis of variance, with exploratory analyses directly comparing the two exercise groups.

Fifty-eight participants were included in the final analysis (morning, n = 20; evening, n = 19; control, n = 19). Significant group × time interactions were observed for FMD, baPWV, systolic blood pressure (SBP), mean arterial pressure (MAP), and plasma NO (all p < 0.05). Both exercise groups increased FMD and reduced SBP, MAP, and baPWV from baseline (all p < 0.05). Plasma NO increased significantly following the evening exercise (p = 0.003), whereas no significant changes were observed following the morning exercise (p = 0.722). At post-intervention, the evening group exhibited lower MAP (p = 0.012) and higher FMD (p = 0.019) and NO levels (p = 0.012) than controls. Exploratory analyses showed a greater baPWV reduction with evening exercise (group × time interaction, p = 0.034). The increase in plasma NO was numerically greater with evening exercise, although the interaction was not statistically significant (p = 0.051).

Exercise timing may influence vascular adaptations in older adults with T2DM, with evening exercise potentially offering additional benefits, particularly for arterial stiffness.

https://www.chictr.org.cn/showproj.html?proj=200163, identifier ChiCTR2300073737.