Author(s): ZHANG, X., YANG, B., HO, Y., ZHANG, Z., WU, D., QIAN, J., Institution: PEKING UNIVERSITY, Country: CHINA, Abstract-ID: 927

INTRODUCTION:
While the optimal timing for exercise to control glucose levels remains unclear, especially regarding the long-term effects of exercise timing, this study aims to investigate the long-term effect of exercise timing in relation to meal times—specifically, pre-meal and post-meal exercise—on glucose homeostasis in young adults with overweight and obesity using continuous glucose monitoring (CGM).
METHODS:
A randomized controlled study was conducted on 34 overweight and obese young adults aged 18 to 35 who underwent a 10-week intervention with different exercise timings. The pre-meal exercise group performed at least 30 minutes of moderate-intensity (65% HRmax) aerobic exercise within 60 minutes before a meal, while the post-meal exercise group performed the same within 0-90 minutes after a meal, five times a week. The exercise intervention was conducted at a smart health station with at least two supervised exercise sessions per week and three self-exercise sessions, monitored by a heart rate belt. The primary outcome was 24-hour continuous glucose levels measured via CGM (SIBIONICS), with secondary outcomes being physical and mental health indicators. Participants maintained their usual dietary habits during the intervention and wore an actiGraph 3X accelerometer to monitor physical activity levels before and after the intervention. Paired t-tests were used for within-group comparisons, and covariance analysis was used for between-group comparisons.
RESULTS:
There were no significant differences in 24-hour mean glucose (98.23±3.16 vs. 97.77±4.22 mg/dL), mean amplitude of glucose fluctuation (MAGE, 31.87±4.37 vs. 33.12±6.82), coefficient of variation of glucose (CV%, 15.68±1.50% vs. 16.92±3.50%) and continuous overall glycemic effect (CONGA,15.37±2.34 vs. 16.11±3.21 mg/dL) between or within the pre-meal and post-meal exercise groups (all p ＞0.05). However, the hypoglycemia index significantly decreased in the pre-meal exercise group (p = 0.039). Regarding mental health indicators, only the pre-meal exercise group showed a significant improvement in mindfulness awareness. After the intervention, both groups increased their daily moderate-intensity physical activity time and reduced their sedentary time.
CONCLUSION:
A 10-week pre- or post-meal exercise intervention did not significantly affect 24-hour continuous glucose levels. Compared to post-meal exercise, pre-meal exercise may reduce the risk of hypoglycemia in young adults with overweight and obesity.