The effect of moderate-intensity aerobic exercise on non-proliferative diabetic retinopathy in type II diabetes mellitus patients: A clinical trial

Diabetic retinopathy (DR) is one of the most threatening complications of diabetes and a leading cause of visual loss in working-age population. Although exercise is beneficial in diabetes, previous studies have showed contradictory and inconclusive results on how it effects DR. In this study, we aimed to investigate the effect of moderate-intensity aerobic exercise on non-proliferative diabetic retinopathy. In this before-after clinical trial, 40 patients with diabetic retinopathy were enrolled by convenient sampling method in Shahid Labbafinejad Hospital in Tehran during 2021–2022. Before the intervention, central macular thickness (CMT, microns) measured by optical coherence tomography (OCT) and fasting blood sugar (FBS, mg/dl) were obtained. Then, patients took part in a 12-week moderate-intensity aerobic exercise (3 sessions per week, each session 45 min). Data were analyzed using SPSS version 26.0. Out of 40 examined patients, 21 (52.5 %) were male and 19 (47.5 %) were female. The mean age of the patients was 50.8 years. The mean rank of FBS (mg/dl) significantly decreased from 21.12 before the exercise to 8.75 after the exercise (p < 0.001). Also, the mean rank of CMT (microns) showed a significant decrease from 21.11 before the intervention to 16.20 after the exercise (p < 0.001). There was a significant positive correlation between patients' age and FBS (mg/dl) before (rho = 0.457, p = 0.003) and after (rho = 0.365, p = 0.021) the intervention. Also, a significant positive correlation was found between patients' age and CMT (microns) before (rho = 0.525, p = 0.001) and after (rho = 0.461, p = 0.003) moderate exercise. Moderate-intensity aerobic exercise leads to lower FBS (mg/dl) and CMT (microns) in patients with diabetic retinopathy, so it may be beneficial for diabetic patients to avoid sedentary lifestyle.