Garthwaite Taru, Sjöros Tanja, Laine Saara, Koivumäki Mikko, Vähä-Ypyä Henri, Norha Jooa, Kallio Petri, Saarenhovi Maria, Löyttyniemi Eliisa, Sievänen Harri, Houttu Noora, Laitinen Kirsi, Kalliokoski Kari K, Vasankari Tommi, Knuuti Juhani, Heinonen Ilkka
Turku PET Centre, University of Turku, Turku University Hospital, and Åbo Akademi University, Turku, Finland.
The UKK Institute for Health Promotion Research, Tampere, Finland.
Scand J Med Sci Sports. 2025 Aug;35(8):e70113. doi: 10.1111/sms.70113.
Impaired metabolic flexibility (MetFlex; the ability to regulate substrate oxidation) and sedentary behavior are both linked to cardiometabolic diseases, but the relationship between the two is not fully elucidated. This study investigated the effects of reduced sedentary time on MetFlex. Sixty-four sedentary adults with metabolic syndrome were randomized into intervention (INT, n = 33) and control (CON, n = 31) groups. INT aimed to reduce sedentary time by 1 h/day by increasing standing and non-exercise physical activity (PA) for 6 months, with continuous accelerometry. Substrate oxidation and MetFlex [ΔRER (respiratory exchange ratio)] from fasting to hyperinsulinemic-euglycemic clamp and low- to maximal-intensity exercise were assessed with indirect calorimetry. Intervention effects between INT and CON were analyzed with mixed models, and secondary analyses examined the effects based on accelerometer-derived behavior changes. INT reduced sedentary time by 41 min/day. Neither insulin- nor exercise-stimulated MetFlex changed in INT or CON, but carbohydrate oxidation during maximal exercise changed differently, favoring INT [INT +2.6 (95% CI: -6.1, 0.8), CON -1.4 (-2.1, 4.9) mg/kg/min; group * time p = 0.03]. In secondary analyses, those who successfully reduced sedentary time by at least 30 min/day (n = 34) improved insulin-stimulated MetFlex and low-intensity exercise fat oxidation compared to the continuously sedentary (n = 30) [ΔRER +0.03 (-0.01, 0.07) vs. -0.02 (-0.06, 0.03); and FATox +0.2 (-0.3, 0.7) vs. -0.4 (-1.0, 1.0) mg/kg/min, group * time p < 0.05]. Changes in insulin-stimulated MetFlex correlated with changes in standing and insulin sensitivity. Thus, successfully reducing daily sitting by at least half an hour can improve MetFlex, with parallel insulin sensitivity enhancements, and aid in cardiometabolic disease prevention in risk populations. Trial Registration: https://www.clinicaltrials.gov/study/NCT03101228.
代谢灵活性受损（MetFlex；调节底物氧化的能力）和久坐行为均与心脏代谢疾病相关，但两者之间的关系尚未完全阐明。本研究调查了减少久坐时间对代谢灵活性的影响。64名患有代谢综合征的久坐不动成年人被随机分为干预组（INT，n = 33）和对照组（CON，n = 31）。INT组旨在通过增加站立和非运动性身体活动（PA），持续6个月，每天减少1小时久坐时间，并采用连续加速度计监测。通过间接测热法评估从空腹到高胰岛素 - 正常血糖钳夹以及从低强度到最大强度运动期间的底物氧化和代谢灵活性[ΔRER（呼吸交换率）]。使用混合模型分析INT组和CON组之间的干预效果，并进行二次分析以检查基于加速度计得出的行为变化的影响。INT组每天久坐时间减少了41分钟。INT组和CON组中，胰岛素刺激和运动刺激的代谢灵活性均未改变，但最大运动期间的碳水化合物氧化变化不同，INT组更有利[INT组增加2.6（95%可信区间：-6.1，0.8），CON组减少1.4（-2.1，4.9）mg/kg/min；组时间p = 0.03]。在二次分析中，与持续久坐的人（n = 30）相比，那些成功将久坐时间每天至少减少30分钟的人（n = 34）改善了胰岛素刺激的代谢灵活性和低强度运动脂肪氧化[ΔRER分别为+0.03（-0.01，0.07）与-0.02（-0.06，0.03）；FATox分别为+0.2（-0.3，0.7）与-0.4（-1.0，1.0）mg/kg/min，组时间p < 0.05]。胰岛素刺激的代谢灵活性变化与站立和胰岛素敏感性变化相关。因此，成功将每日坐姿时间减少至少半小时可改善代谢灵活性，同时增强胰岛素敏感性，并有助于预防高危人群的心脏代谢疾病。试验注册：https://www.clinicaltrials.gov/study/NCT03101228 。
