原创 毛毛弟 一起学科研 2022-04-27 10:00
“护”说科研
Abstract
摘要
Sedentary behaviour-put simply, too much sitting, as a distinct concept from too little exercise-is a novel determinant of cardiovascular risk. This definition provides a perspective that is complementary to the well-understood detrimental effects of physical inactivity. Sitting occupies the majority of the daily waking hours in most adults and has become even more pervasive owing to the COVID-19 pandemic. The potential for a broad cardiovascular health benefit exists through an integrated approach that involves ‘sitting less and moving more’. In this Review, we first consider observational and experimental evidence on the adverse effects of prolonged, uninterrupted sitting and the evidence identifying the possible mechanisms underlying the associated risk. We summarize the results of randomized controlled trials demonstrating the feasibility of changing sedentary behaviour. We also highlight evidence on the deleterious synergies between sedentary behaviour and physical inactivity as the underpinnings of our case for addressing them jointly in mitigating cardiovascular risk. This integrated approach should not only reduce the specific risks of too much sitting but also have a positive effect on the total amount of physical activity, with the potential to more broadly benefit the health of individuals living with or at risk of developing cardiovascular disease
久坐行为--简单地说，就是坐得太多，与运动太少是一个不同的概念--是心血管风险的一个新的决定因素。这个定义提供了一个与众所周知的缺乏体力活动的有害影响相辅相成的视角。坐着的时间占了大多数成年人每天清醒时间的大部分，由于COVID-19的流行，坐着的时间甚至变得更加普遍。通过“少坐多动”的综合方法，有可能对心血管健康产生广泛的益处。在本综述中，我们首先考虑了关于长期、不间断坐着的不良影响的观察和实验证据，以及确定相关风险的可能机制的证据。我们总结了随机对照试验的结果，证明了改变久坐行为的可行性。我们还强调了久坐行为和缺乏体力活动之间的有害协同作用的证据，作为我们在减轻心血管风险方面共同解决它们的基础。这种综合方法不仅可以减少久坐的具体风险，而且对体力活动的总量也有积极的影响，有可能更广泛地惠及心血管疾病患者或有患病风险者的健康。
Sedentary behaviours that typically involve long periods of sitting during waking hours might have physiological consequences that are distinct from those of a lack of moderate–vigorous-intensity physical activity, often referred to as exercise. Many adults spend more than half of their waking hours sitting, with this pattern further amplified by the coronavirus disease 2019 (COVID-19) pandemic. In this Review, we make a case for an approach to preventing and managing cardiovascular disease that involves ‘sitting less and moving more’. This approach can build on the well-established role of exercise in cardiovascular disease prevention and rehabilitation. Observational and experimental evidence on the likely cardiovascular health benefits of reducing and regularly interrupting sitting time are the basis of this approach along with an emerging understanding of the biological mechanisms that point to a rational basis for doing so.
通常涉及在清醒时间长时间坐着的久坐行为可能会产生生理后果，这与缺乏中等强度的体力活动（通常称为运动）的后果不同。许多成年人在醒着的时候有一半以上的时间是坐着的，这种模式因2019年冠状病毒疾病（COVID-19）的流行而进一步扩大。在本评论中，我们提出了一种预防和管理心血管疾病的方法，包括“少坐多动”。这种方法可以建立在运动在心血管疾病预防和康复中的公认作用之上。观察和实验证据表明，减少和定期中断坐着的时间可能对心血管健康有好处，这是这种方法的基础，同时也是对生物机制的新的理解，这也是这样做的合理依据。
Physical inactivity, defined as a level of activity that is insufficient to meet current physical activity guidelines, has long been known to be a major contributor to the risk of cardiovascular disease. Physical activity levels are lowest among older adults (aged ≥65 years), who are also at the highest risk of cardiovascular disease compared with all other age groups. New ways to understand and influence the health risks of physical inactivity are now emerging. The lack of regular physical activity and the large amounts of time spent in sedentary behaviours (defined as any waking behaviour characterized by an energy expenditure <1.5 times the basal metabolic rate, that is, 1.5 metabolic equivalent of task (MET), while in a sitting, lying or reclining posture) can have both distinct and interrelated influences on cardiovascular risk. Furthermore, adults can meet or exceed public health guidelines for physical activity but also spend most of their waking hours sitting (Fig. 1).
长期以来，人们都知道，缺乏体力活动，即活动量不足以满足当前的体力活动指南，是导致心血管疾病风险的一个主要因素。老年人（年龄≥65岁）的体力活动水平最低，与所有其他年龄组相比，他们的心血管疾病风险也最高。目前，理解和影响缺乏体力活动的健康风险的新方法正在出现。缺乏定期的体力活动和大量时间用于久坐行为（定义为任何清醒的行为，其特点是在坐着、躺着或躺着的姿势下，能量消耗<1.5倍基础代谢率，即1.5个代谢当量的任务（MET）），对心血管风险既有明显的影响，也有相互关联的影响。此外，成年人可以达到或超过公共卫生指南中的体力活动，但也会在醒着的大部分时间里坐着（图1）。
Particularly informative insights have come from advances in the device-based measurement of physical activity. Over the past seven decades of physical activity and health research, the observational studies and intervention trials relied on participant reports of exposures and outcomes. Measurement error was a widely recognized problem, limiting what could be inferred from the research findings. Technological advances have overcome many of the inherent limitations of the previous generation of studies and the more precise measurements available are delivering new research insights. Small, wearable, research-grade devices (accelerometers) can now provide data across an entire day (Fig. 2). Findings from studies that used device-based measurement capacities have provided a more precise and comprehensive perspective than self-reported measures of the total spectrum of activity by identifying the large amounts of time that most adults spend sitting, in light-intensity physical activity (both of which were poorly characterized by self-reported measures), and in moderate-intensity and vigorous-intensity physical activity.
特别是基于设备的体力活动测量的进展带来了丰富的见解。在过去七十年的体力活动和健康研究中，观察性研究和干预试验依赖于参与者对暴露和结果的报告。测量误差是一个被广泛认可的问题，限制了从研究结果中推断出的内容。技术进步已经克服了上一代研究的许多固有限制，更精确的测量正在提供新的研究见解。小型、可穿戴的研究级设备（加速度计）现在可以提供整个一天的数据（图2）。使用基于设备的测量能力的研究结果提供了一个比自我报告的总活动范围更精确和全面的视角，确定了大多数成年人在坐着、从事轻度体力活动（自我报告的测量对这两种活动的描述都很差）、以及从事中度和高强度体力活动的大量时间。
Of note, device-based measures have reaffirmed that high levels of sedentary behaviour are unfavourably associated with overall physical activity levels. Specifically, a strong inverse relationship exists between sedentary behaviour and total physical activity, with the strongest associations observed for light-intensity physical activity. This inverse relationship highlights a fundamental principle that any time spent in sedentary behaviour displaces time spent in total physical activity. The effects of the COVID-19 pandemic have amplified the importance of addressing the balance between sedentary behaviour and physical activity. For example, early evidence suggests that risk mitigation strategies, such as social distancing and ‘stay at home’ orders, have resulted in large reductions in physical activity and substantial increases in sedentary time, particularly among individuals who were previously physically active (Fig. 2a). The extraordinary challenges and remaining uncertainties imposed by the global COVID-19 health crisis have the potential to further escalate the pandemic of physical inactivity and sedentary behaviour (Fig. 2a). Therefore, we have a strong imperative, perhaps more than ever, to find ways to create a healthier balance through sitting less and moving more.
值得注意的是，基于设备的测量方法再次证实，高水平的久坐行为与总体体力活动水平有不利的联系。具体来说，在久坐行为和总的体力活动之间存在着强烈的反比关系，在轻强度的体力活动中观察到最强的关联。这种反比关系突出了一个基本原则，即任何花在久坐行为上的时间都会取代花在总体力活动上的时间。COVID-19大流行的影响放大了解决久坐行为和体力活动之间平衡的重要性。例如，早期的证据表明，减轻风险的策略，如社会疏远和“呆在家里”的命令，已经导致体力活动的大量减少和久坐时间的大量增加，特别是在以前体力活动积极的人（图2a）。全球COVID-19健康危机带来的非同寻常的挑战和仍然存在的不确定性，有可能使缺乏体力活动和久坐行为的大流行进一步升级（图2a）。因此，我们非常有必要，也许比以往任何时候都更有必要找到方法，通过少坐多动来创造一个更健康的平衡。
Figure 2b shows examples of daily patterns of sitting time and movement assessed by an activity monitor device and illustrates how these device-based measurement capacities can provide new perspectives through more powerful and finer-resolution lenses. These devices have considerably sharpened the scientific focus that can help to characterize daily activity with higher degrees of precision, particularly with new insights into the under-recognized role of sedentary behaviour (not only the total time spent sitting but also the patterns of sitting time, including brief, physically active interruptions).
图2b显示了由活动监测设备评估的日常坐姿时间和运动模式的例子，并说明了这些基于设备的测量能力如何通过更强大和更精细的分辨率镜头提供新的视角。这些设备大大加强了科学焦点，可以帮助以更高的精度来描述日常活动的特征，特别是对久坐行为的作用认识不足的新见解（不仅是坐着的总时间，还有坐着的时间模式，包括短暂的、体力活动的中断）。
Observational evidence
观察性证据
Understanding the health risks of sitting has consolidated rapidly over the past two decades in a broad body of scientific findings. Sedentary behaviour is now explicitly identified in new clinical and public-health guidelines on reducing sitting time in addition to increasing physical activity and exercise. Notably, the first recommendation of the 2018 US Physical Activity Guidelines for adults (18–64 years) and older adults (≥65 years) emphasizes the promotion of sitting less and moving more for all and that doing some physical activity is better than none, while those who sit less and do any amount of moderate–vigorous-intensity physical activity gain some health benefits. Below, we elaborate on this evidence and highlight the population health implications of excessive sitting for cardiovascular outcomes.
在过去的20年里，对坐着的健康风险的理解在大量的科学发现中迅速巩固。现在，在新的临床和公共卫生指南中明确指出，除了增加体力活动和运动外，还要减少坐的时间。值得注意的是，2018年美国成人（18-64岁）和老年人（≥65岁）体力活动指南的第一条建议强调提倡所有人少坐多动，做一些体力活动比不做更好，而那些少坐并做任何数量的中等强度体力活动的人获得一些健康益处。下面，我们将详细阐述这一证据，并强调过度坐着对心血管结果的人口健康影响。
Population-based studies using self-reported measures suggest that daily sitting time in adults typically ranges between 5 and 8 hours. The examination of trends over the past 10 years suggests that self-reported sedentary time has increased by around 1 hour per day. In the USA, findings from the NHANES study revealed that, based on self-reported measures, the proportion of adults who do not adhere to physical activity guidelines and sit for >6 hours per day increased from 16.1% in 2007–2008 to 18.8% in 2015–2016 (ref. 15). These findings are plausible and are in accordance with commonsense observations of social, technological and other changes currently influencing the lifestyle of large numbers of adults. However, device-based estimates from population studies and large cohorts show that the mean daily sedentary time in adults might actually be much higher than indicated in previous estimates that were based on self-reports and, indeed, could be in the range of 7.7–11.5 hours per day. This increased sitting time has substantial implications for cardiovascular risk.
以人口为基础的研究使用自我报告的措施表明，成年人每天坐的时间通常在5到8小时之间。对过去10年趋势的研究表明，自我报告的久坐时间每天增加了约1小时。在美国，NHANES研究的结果显示，根据自我报告的措施，不遵守体力活动指南和每天坐着超过6小时的成年人的比例从2007-2008年的16.1%增加到2015-2016年的18.8%（参考文献15）。这些发现是合理的，符合目前影响大量成年人生活方式的社会、技术和其他变化的常识性观察。然而，来自人口研究和大型队列的基于设备的估计显示，成人的平均每日久坐时间实际上可能比以前基于自我报告的估计要高得多，事实上，可能在每天7.7-11.5小时之间。这种坐着的时间增加对心血管风险有很大影响。
Findings from numerous observational studies using device-based measurements have provided important insights into the health consequences of these large volumes of sitting time. For example, in a geographically diverse, biracial US sample of middle-aged and older adults (≥45 years), device-measured total sedentary time and prolonged, uninterrupted sedentary bouts were both associated with an increased risk of all-cause death after consideration of the influence of physical activity. Further examination of these datamodelled the influence of replacing sedentary time with more active time21. This analysis identified a substantial reduction in all-cause mortality in less active adults in the study but not among those who were more active (who engaged in a total of 3.5 hours per day of light-intensity and moderate-intensity physical activity). Concordant findings emerged from the study of older women (mean age 79 years) participating in the Women’s Health Initiative (a racially and ethnically diverse study sub-cohort aged 63–97 years). Both high sedentary time and longer mean sedentary bout durations were associated with the risk of cardiovascular disease in a dose–response manner. This association remained after accounting for health status, physical function and cardiovascular disease risk factors, including moderate–vigorous physical activity. A further examination of this cohort found a relationship between sedentary time and the prevalence of diabetes mellitus. Together, this set of prospective epidemiological findings that are based on device-derived measures emphasize the importance of less time spent in sedentary behaviours and of shorter sedentary bouts in those aged ≥45 years.
许多使用设备测量的观察性研究的结果为这些大量坐着的时间的健康后果提供了重要的见解。例如，在一个地域多样化的美国中老年（≥45岁）样本中，考虑到体力活动的影响后，设备测量的总久坐时间和长时间、不间断的久坐时间都与全因死亡的风险增加有关。对这些数据的进一步研究模拟了用更多的活动时间来取代久坐时间的影响。这项分析发现，研究中不太活跃的成年人的全因死亡率大大降低，但那些比较活跃的人（每天总共从事3.5小时的轻度和中度强度的体力活动）则没有。参加妇女健康倡议的老年妇女（平均年龄79岁）的研究（一个种族和民族多样化的研究子群，年龄在63-97岁）出现了一致的发现。高久坐时间和较长的平均久坐时间都与心血管疾病的风险有关，呈剂量反应方式。在考虑了健康状况、身体功能和心血管疾病风险因素（包括中等强度的体力活动）后，这种关联仍然存在。对这一队列的进一步检查发现，久坐时间和糖尿病的发病率之间有关系。总的来说，这组基于设备测量的前瞻性流行病学发现强调了在年龄≥45岁的人群中减少久坐行为的时间和缩短久坐时间的重要性。
Despite the effects of sedentary behaviour on total physical activity levels, studies in young (mean age 22 years) and older (mean age 64 years) adults have shown that device-measured sedentary time is inversely associated with measures of cardiorespiratory fitness and functional fitness, even after adjusting for time spent in moderate–vigorous-intensity activity, suggesting that the health risks associated with sedentary behaviour might be attenuated by increasing fitness levels. Furthermore, evidence from the Danish Health Examination Survey indicates that the influence of self-reported sitting time on cardiorespiratory fitness is most pronounced in individuals with low levels of physical activity. Epidemiological evidence suggests that cardiorespiratory fitness moderates the association between sedentary behaviour and cardiometabolic risk factors, such that weaker associations are observed in individuals with higher fitness levels. Only high levels of cardiorespiratory fitness (>43.3 ml/kg/min in men and >35.2 ml/kg/min in women) seem to fully mitigate the deleterious associations between high levels of sitting time and cardiometabolic risk. Although an increase in fitness levels might lead to greater improvements in cardiovascular risk factors, the activity levels required to achieve this improvement are high. Furthermore, frequent, brief physically active interruptions to sedentary time have the potential to lead to improved fitness and health.
尽管久坐行为对总的体力活动水平有影响，但对年轻人（平均年龄22岁）和老年人（平均年龄64岁）的研究表明，即使在调整了中等强度活动的时间后，设备测量的久坐时间与心肺健康和功能健康的测量结果成反比，这表明与久坐行为有关的健康风险可能会通过提高适能水平而减弱。此外，来自丹麦健康检查调查的证据表明，自我报告的坐着的时间对心肺功能的影响在体力活动水平低的人中最为明显。流行病学证据表明，心肺健康状况可以调节久坐行为和心脏代谢风险因素之间的关联，因此，在适能水平较高的个体中观察到的关联较弱。只有高水平的心肺功能（男性>43.3毫升/公斤/分钟，女性>35.2毫升/公斤/分钟）似乎才能完全缓解高坐时间和心脏代谢风险之间的有害关联。尽管适能水平的提高可能会导致心血管风险因素的更大改善，但实现这种改善所需的活动水平很高。此外，频繁的、短暂的体力活动打断久坐时间有可能导致体适能和健康的改善。
The evidence described above is part of a broader body of work reported over the past decade, with accumulating, highly informative evidence from prospective epidemiological studies documenting that long periods of time spent in sedentary behaviour can lead to adverse health outcomes-particularly for cardiovascular disease. The comprehensive review undertaken by the 2018 Physical Activity Guidelines Advisory Committee for the second edition of the Physical Activity Guidelines for Americans has been pivotal in synthesizing the evidence in terms of the relationships between sedentary behaviour (at this point in time largely from studies using self-reported measures) and health outcomes in adults.
上述证据是过去十年报告的更广泛的工作的一部分，来自前瞻性流行病学研究的不断积累、高度翔实的证据记录了长时间的久坐行为会导致不利的健康结果--尤其是心血管疾病。2018年体力活动指南咨询委员会为第二版《美国人体力活动指南》所做的全面审查，在总结久坐行为（目前主要来自使用自我报告措施的研究）与成人健康结果之间关系的证据方面起到了关键作用。
Table 1 summarizes the findings from the Physical Activity Guidelines Advisory Committee that are relevant to cardiovascular disease. The main conclusion is that strong evidence is available to support that exposure to high volumes of sitting time significantly increases the risk of all-cause and cardiovascular death and the incidence of cardiovascular disease and type 2 diabetes mellitus. Furthermore, findings from a systematic review and harmonized meta-analysis of accelerometer-assessed sedentary time showed that higher amounts of sedentary time are associated with an increased risk of all-cause death. Conversely, higher levels of total physical activity — regardless of intensity level — are associated with a lower risk of all-cause death. Across increasing quartiles of sedentary time (relative to the first quartile; median range 371–519 minutes per day), the hazard ratios for all-cause mortality were 1.28, 1.71 and 2.63 for the second quartile (469–588 minutes per day), third quartile (542–639 minutes per day) and fourth quartile (624–705 minutes per day), respectively. Relative to the first quartile of total physical activity (53–196 counts per minute (CPM)), the hazard ratios for all-cause mortality were 0.48, 0.34 and 0.27 for the second quartile (134–291 CPM), third quartile (199–371 CPM) and fourth quartile (304–522 CPM), respectively.
表1总结了体力活动指南咨询委员会与心血管疾病有关的调查结果。主要结论是，有强有力的证据支持，暴露在大量的坐着的时间中会显著增加所有原因和心血管死亡的风险，以及心血管疾病和2型糖尿病的发病率。此外，对加速器评估的久坐时间的系统评价和Meta分析结果显示，较多的久坐时间与全因死亡的风险增加有关。相反，较高的总体力活动水平--无论强度水平如何--与较低的全因死亡风险有关。在静坐时间不断增加的四分位数中（相对于第一四分位数；中位数范围为每天371-519分钟），第二四分位数（每天469-588分钟）、第三四分位数（每天542-639分钟）和第四四分位数（每天624-705分钟）的全因死亡危险比分别为1.28、1.71和2.63。相对于总体力活动的第一四分位数（每分钟53-196次），第二四分位数（134-291次）、第三四分位数（199-371次）和第四四分位数（304-522次）的全因死亡率的危险比分别为0.48、0.34和0.27。
Further insights from studies using isotemporal modelling approaches indicate that replacing bouts of sitting time (30–60 minutes) with either light or moderate– vigorous-intensity physical activity is associated with reductions in all-cause and cardiovascular mortality and cardiometabolic risk markers, particularly among less-active adults. Consistently, stronger associations are seen when sitting time is replaced by moderate– vigorous-intensity physical activity. This association has been confirmed in later studies using device-based measures in older populations aged ≥70 years. For example, in a study of >3,000 older men and women, every 30-minute increment per day in light-intensity activity or moderate–vigorous-intensity physical activity was associated with 11% and 36% decreases in the risk of cardiovascular disease or all-cause death, respectively. By contrast, every 1-hour per day increment in sedentary time increased the risk of these outcomes by 33%.
使用等时建模方法的研究得出的进一步见解表明，用轻度或中度-剧烈强度的体力活动来取代一段时间的坐着的时间（30-60分钟）与所有原因和心血管死亡率以及心脏代谢风险指标的降低有关，特别是在不太活跃的成年人中。一致的是，当坐着的时间被中度-剧烈强度的体力活动取代时，会看到更强的关联。这种关联在后来的研究中得到了证实，这些研究使用基于设备的测量方法，在年龄≥70岁的老年人群中进行。例如，在一项对超过3000名老年男性和女性的研究中，每天每增加30分钟的轻度强度活动或中度-剧烈强度的体力活动，与心血管疾病或所有原因死亡的风险分别减少11%和36%有关。相比之下，每天久坐的时间每增加1小时，这些结果的风险就会增加33%。
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