Heinonen Ilkka
Turku PET Centre, University of Turku and Turku University Hospital, Turku, Finland.
Front Physiol. 2024 Mar 14;15:1348122. doi: 10.3389/fphys.2024.1348122. eCollection 2024.
Sedentary behavior, defined as sitting with low energy expenditure, has emerged as a modifiable risk factor that affects our physiology and health. Evidence for the detrimental effects of sedentary behavior/physical inactivity on health, however, stems largely from epidemiological studies, which cannot address causalities. Acute and short-term sedentary behavior reduction interventions have been performed; however, in these studies, sitting has often been replaced by formal physical activity options, such as exercise, and long-term studies in subjects with cardiometabolic risk factors are still relatively few. We have recently conducted a long-term randomized controlled trial (RCT) to reduce daily sitting, without formal exercise, in metabolic syndrome patients, and this mini-review presents these studies with physiological aspects. The findings indicate that sedentary behavior reduction can prevent the increase in levels of many cardiometabolic risk factors after 3 months, but more intense physical activity rather than only reducing daily sitting time may be needed to further reduce the risk factor levels. At 6-month time point reduced sitting reduced fasting insulin, while successfully reducing sitting and body fat had beneficial effects also on whole-body insulin sensitivity, but other effects were relatively minor. Reduced sitting did not improve maximal aerobic fitness after 6 months, but an increase in daily steps was positively associated with an increase in fitness. However, the more the participants replaced sitting with standing, the more their maximal aerobic fitness was reduced. Overall, although the analysis of the collected data is still ongoing, our RCT findings suggest that the physiological and health effects of reduced sitting are relatively minor and that physical activities such as taking more daily walking steps are needed, which would be more beneficial and time-efficient for improving human health.
久坐行为被定义为能量消耗较低的坐姿，已成为一种可改变的风险因素，会影响我们的生理和健康。然而，久坐行为/缺乏身体活动对健康产生有害影响的证据主要来自流行病学研究，而这些研究无法确定因果关系。已经开展了减少急性和短期久坐行为的干预措施；然而，在这些研究中，久坐往往被正式的体育活动（如锻炼）所取代，针对有心脏代谢风险因素的受试者的长期研究仍然相对较少。我们最近进行了一项长期随机对照试验（RCT），在不进行正式锻炼的情况下减少代谢综合征患者的每日久坐时间，本综述介绍了这些涉及生理方面的研究。研究结果表明，减少久坐行为可以在3个月后防止许多心脏代谢风险因素水平的升高，但可能需要更剧烈的体育活动而不仅仅是减少每日久坐时间，以进一步降低风险因素水平。在6个月的时间点，减少久坐可降低空腹胰岛素水平，同时成功减少久坐和体脂对全身胰岛素敏感性也有有益影响，但其他影响相对较小。减少久坐在6个月后并未改善最大有氧适能，但每日步数的增加与适能的增加呈正相关。然而，参与者用站立代替坐姿的次数越多，他们的最大有氧适能下降得就越多。总体而言，尽管对收集到的数据的分析仍在进行中，但我们的随机对照试验结果表明，减少久坐对生理和健康的影响相对较小，需要进行如增加每日步行步数等体育活动，这对改善人类健康将更有益且更具时效性。
