Table 4_Acute effects of exercise snacks on postprandial glucose and insulin metabolism in adults with obesity: a systematic review and meta-analysis.docx

ObjectiveTo quantify the acute effects of brief, frequent interruptions to prolonged sitting (“exercise snacks”) on postprandial glucose and insulin in adults with obesity, and to explore potential effect modifiers.
Data sources and methodsFollowing PRISMA 2020, seven sources (PubMed, Web of Science, Cochrane Library, Embase, ClinicalTrials.gov, ICTRP, CINAHL) were searched to July 10, 2025. Randomized crossover or parallel trials in adults with obesity comparing activity breaks with uninterrupted sitting were included. Co-primary outcomes were glucose and insulin incremental area under the curve (iAUC); secondary outcomes were total AUC (tAUC) and mean levels. Random-effects meta-analyses synthesized standardized or mean differences (95% CI); heterogeneity was quantified by I2. Prespecified subgroup and sensitivity analyses were undertaken; small-study effects were examined when k ≥ 10. Risk of bias was appraised with Cochrane RoB 2.0 (fixed-effect estimates were additionally inspected when heterogeneity was low to moderate).
ResultsSeventeen trials (261 unique participants; predominantly randomized crossover) were included. Versus uninterrupted sitting, activity breaks reduced glucose iAUC (SMD = −0.49, 95% CI –0.85 to −0.14; I2 = 76%) and reduced insulin iAUC (SMD = −0.26, 95% CI –0.50 to −0.03; I2 = 44%). Glucose tAUC and mean glucose showed non-significant downward trends. Mean insulin decreased (SMD = −0.54, 95% CI –0.97 to −0.10), albeit with high heterogeneity (I2 = 76%). Exploratory subgroup analyses suggested larger effects with higher-frequency (≤30-min) and short-bout (≤3-min) interruptions and with walking or simple resistance, although tests for subgroup differences were generally non-significant. Meta-regressions showed age predicted glucose iAUC, BMI and interruption frequency predicted mean insulin, no moderator predicted insulin iAUC, and intervention intensity (daily MET) had minimal, non-significant effects. Findings were robust in leave-one-out and model-assumption sensitivity analyses, with no clear small-study effects for glucose outcomes.
ConclusionIn adults with obesity, interrupting sitting about every ≤30 min with 2–5 min of light-to-moderate walking or simple resistance acutely attenuates postprandial glucose and insulin responses. These findings support exercise “snacks” as a pragmatic behavioral strategy, while longer-term randomized trials are needed to define durability and refine dose parameters.
Systematic review registrationhttps://www.crd.york.ac.uk/PROSPERO/view/CRD420251144139, Identifier CRD420251144139.

研究目的：本研究旨在量化长时间久坐期间实施短暂、频繁中断（即“运动零食（exercise snacks）”）对肥胖成人餐后血糖与胰岛素水平的急性影响，并探究潜在的效应调节因素。
数据来源与方法：遵循PRISMA 2020声明，检索截至2025年7月10日的7个数据库，包括PubMed、Web of Science、Cochrane图书馆、Embase、ClinicalTrials.gov、国际临床试验注册平台（ICTRP）、护理及相关健康文献累积索引（CINAHL）。纳入对比活动中断与持续久坐的肥胖成人随机交叉试验或平行对照试验。共同主要结局为血糖与胰岛素的曲线下增量面积（incremental area under the curve, iAUC）；次要结局为曲线下总面积（total AUC, tAUC）与平均水平。采用随机效应Meta分析合并标准化均数差或均数差（95%置信区间），通过I²统计量量化异质性。开展预先设定的亚组分析与敏感性分析；当纳入研究数k≥10时，检验小样本效应。采用Cochrane偏倚风险评估工具2.0（Cochrane RoB 2.0）评价偏倚风险（当异质性为低至中度时，额外检视固定效应估计值）。
研究结果：共纳入17项试验，涉及261名独特受试者，以随机交叉试验为主。与持续久坐相比，活动中断可降低血糖iAUC（标准化均数差standardized mean difference, SMD=-0.49，95%置信区间-0.85~-0.14；I²=76%），同时降低胰岛素iAUC（SMD=-0.26，95%置信区间-0.50~-0.03；I²=44%）。血糖tAUC与平均血糖水平呈无统计学意义的下降趋势；平均胰岛素水平降低（SMD=-0.54，95%置信区间-0.97~-0.10），但异质性较高（I²=76%）。探索性亚组分析显示，当中断频率更高（≤30分钟/次）、单次时长更短（≤3分钟）、采用步行或简单抗阻运动时，干预效应更大，但亚组差异检验总体无统计学意义。Meta回归分析显示，年龄可预测血糖iAUC，体质量指数（BMI）与中断频率可预测平均胰岛素水平，无调节因素可预测胰岛素iAUC，干预强度（每日代谢当量MET）的效应微弱且无统计学意义。逐一剔除敏感性分析与模型假设敏感性分析结果均稳健，血糖结局未显示明确的小样本效应。
研究结论：对于肥胖成人，每≤30分钟中断久坐，辅以2~5分钟轻至中度步行或简单抗阻运动，可急性减弱餐后血糖与胰岛素应答。本研究结果支持“运动零食”作为实用的行为干预策略，未来仍需开展长期随机试验以明确其效应持久性并优化剂量参数。
系统评价注册信息：https://www.crd.york.ac.uk/PROSPERO/view/CRD420251144139，注册标识符为CRD420251144139。