Clinical application of Chester Step Test in developing personalized exercise prescription in patients with type 2 diabetes: A single-blind, randomized controlled trial

BACKGROUND: Hyperglycemia is a significant risk factor for cardiovascular disease in patients with type 2 diabetes (T2D). Personalized exercise prescriptions are one of the most effective methods for lowering blood glucose levels, but they are typically prescribed in laboratory settings. The Chester Step Test (CST) is a submaximal fitness test used to assess one's cardiovascular fitness, particularly their aerobic capacity or VO2 max. However, studies utilizing the CST to develop personalized exercise programs for glycemic management are rare. This study explored the effects of personalized exercise prescriptions, versus non-exercise control on the glycemic profiles of patients with T2D under free-living conditions. METHODS: This was a single-center, single-blind study enrolled 38 outpatients diagnosed with T2D between April 2022 and August 2024. Patients were randomly assigned, using a random number table, to either the exercise group (EX, n = 19) or the control group (CON, n = 19), allocation ratio of 1:1. In the EX group, participants completed a CST to assess their VO2 max. Based on VO2 max results and exercise preferences, an exercise physician prescribed a personalized exercise program at 50% to 75% VO2 max intensity, scheduled 45 minutes after dinner for 30 to 60 minutes. The CON group continued their usual daily routines without engaging in any vigorous physical activity. Data were monitored with a continuous glucose monitoring system and analyzed using repeated measures-analysis of variance. RESULTS: On exercise days, the EX group showed lower postprandial nadir glucose (4.5 ± 1.15 mmol/L vs 5.4 ± 0.98 mmol/L, P = .0160), reduced blood glucose standard deviation (1.5 ± 0.41 mmol/L vs 2 ± 0.36 mmol/L, P = .0272), and decreased mean amplitude of glycemic excursions (3.6 ± 1.86 mmol/L vs 5.5 ± 1.82 mmol/L, P = .0094) compared to CON group. Although some metrics, such as continuous overall net glycemic action and low blood glucose index showed no significant changes, these results suggest personalized exercise, prescribed according to CST test, effectively stabilizes blood glucose variability. CONCLUSIONS: Under free-living conditions, the personalized exercise prescription based on CST effectively reduced glycemic variability in T2D patients.