Diabetes Care Volume 44, January 2021 17 COMMENTARY Mary O. Whipple,1,2,3 Is Being Physically Active Enough Judith G. Regensteiner,2,3 and to Be Metabolically Healthy? The Audrey Bergouignan4,5 Key Role of Sedentary Behavior Diabetes Care 2021;44:17–19 | https://doi.org/10.2337/dci20-0064 Low levels of physical activity (PA) are and early mortality (7,8), even in people with higher metabolic risk score, inde- now well recognized as a major public who exercise regularly. These observa- pendent of age and sex. They conclude health problem, implicated in cancer, tions raise obvious questions: Are the that even among highly active older cardiovascular disease (CVD), metabolic effects of SB independent from those adults, SB is associated with increased syndrome, diabetes, and early mortality of PA or simply the “other side of the metabolic risk(Fig.1).Thus,MVPA andSB (1). PA guidelines (i.e., $150 min/week coin”?Whatistheminimumlevelof appear to be independent predictors of of moderate activity or $75 min/week of MVPA needed to counteract the adverse metabolic risk, as the negative health vigorous activity, collectively referred to health effects of SB? effects of SB are not fully offset by even as moderate to vigorous physical activity A recent harmonized meta-analysis of extremely high levels of MVPA. [MVPA]) are globally promoted to pro- data from more than 1 million adults This study adds to SB literature in tect the population against the risk of showed that high levels of PA (i.e., about several meaningful ways. Even in a pop- developing chronic disease. But is this 60–75 min/day of MVPA) are needed to ulation of Masters athletes reaching sufficient to promote metabolic health? eliminate the effect of 9 h/day of SB on “ceiling levels” of PA who have likely The relationship between PA and health mortality (9). Even if this exceeds the been active most of their lives, SB is not appears to be more complex than initially current PA recommendations, this ob- only highly prevalent but also similar to thought, and another component has servation suggests that once we reach sedentary levels of inactive older adults been attracting attention over the past such levels, we should be free of the (11). Furthermore, SB is still strongly decade: sedentary behavior (SB). Al- effects of SB on health. In this issue of associated with metabolic risk. This high- though they are often used interchange- Diabetes Care, Madden et al. report that lights the importance of understanding ably, SB is fundamentally different from SB adversely influences metabolic health and potentially intervening on both physical inactivity. While physical inac- even in the presence of large volumes of physical inactivity (too little exercise) tivity is defined as engaging in less PA MVPA (10). In this study, the relationship and high levels of SB (too much sitting). than necessary to meet the current between objectively measured SB, light This study is clinically important given guidelines (2), SB describes “any waking physical activity (LPA), MVPA, and met- that SB has been recognized as a major behavior characterized by an energy abolic syndrome risk score was examined risk factor for many metabolic diseases expenditure #1.5 metabolic equivalents in 54 older adults. Notably, study par- (12). Studying a highly physically active (METs) while in a sitting or reclining ticipants had remarkably high levels of group of older adults lays the ground- posture” (3). Thus, individuals can be MVPA (2.6 h/day), 2 h more than the work for delineating the independent both physically active and highly seden- current recommendations (2) and more role of SB in the relationship between PA tary (4,5). Increased time spent sitting than seven times that of typical older and health, as sitting too much may have raises the risk for metabolic syndrome adults (11). The authors found that different health implications than lack (6), incident CVD, CVD-related risk factors, greater sedentary time was associated of MVPA. 1Division of Geriatric Medicine, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 2Division of General Internal Medicine, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 3Center for Women’s Health Research, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 4Division of Endocrinology, Metabolism, and Diabetes, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 5Universite´ de Strasbourg, CNRS, IPHC UMR 7178, Strasbourg, France Corresponding author: Audrey Bergouignan, [email protected] © 2020 by the American Diabetes Association. Readers may use this article as long as the work is properly cited, the use is educational and not for profit, and the work is not altered. More information is available at https://www.diabetesjournals.org/content/license. See accompanying article, p. 194. 18 Commentary Diabetes Care Volume 44, January 2021 The study by Madden et al. (10) has important for our understanding of po- Critically, we must determine what numerous strengths. First, studying the tential sex differences in relationships strategies or combination of strategies role of SB in a highly active group of between SB, PA, and health (18). are effective in reducing SB through an people is an innovative approach to There are also a few limitations to this increase in both MVPA and LPA. LPA, unraveling the importance (and unique study. First, as the authors acknowl- which includes everyday activities such contribution) of SB versus MVPA. Addi- edge, the study utilized a SenseWear as walking, housework, or taking the tionally, the focus on older adults is armband,whichhasbeenshowntobe stairs (activities requiring 1.5–2.9 METs), critical, as older adults tend to be highly inaccurate at high-intensity activity lev- is tightly related to time spent in SB, sedentary (13) and are especially vulner- els (19,20). Additionally, an upper-arm as one typically offsets the other. The able to the negative effects of SB due to monitor is not as accurate as a posture literature on SB, LPA, and MVPA to date the high burden of cardiometabolic risk monitor (e.g., activPAL mounted on the indicates that we must target and act factors (14,15). Second, the use of an thigh) for classification of SB. Second, it on each in order to improve metabolic objective measure of SB is a significant is unclear how the increased metabolic health (22). This is particularly important strength, as self-report typically results in risk score may translate into CVD in this since efforts targeting an increase in underestimation of SB (16). The use of a population, although the authors do MVPA among sedentary adults can in- compositional analysis should also be indicate that the mean difference noted advertently lead to behavioral compen- commended, as it accounts for the co- between their high and low groups sation, in which an individual decreases dependence of time in different activity was associated with approximately 1.5- their LPA and increases their SB in re- types and is one of the most robust fold risk of cardiovascular events in the sponse to exercise (23,24). Additionally, choices for analyzing these types of Multi-Ethnic Study of Atherosclerosis the study by Madden et al. does not data (17). Third, the use of a continuous (MESA) cohort (21). Understanding if/ address the minimum amount of MVPA score for metabolic risk, as opposed to how these differences in metabolic risk needed to offset the effects of SB. Even dichotomous presence/absence of met- score lead to future metabolic disease though these participants were highly abolic syndrome is important, as it and CVD, as well as how the metabolic active, this level of MVPA was not suf- enables evaluation of the association risk of the subjects studied by Madden ficient to offset the effects of spending an between SB and metabolic risk in health- et al. compares to that of inactive older average of 9.4 sedentary hours per day ier individuals, rather than simply id- adults, is essential. Third, this study is among healthy older adults, unlike what entifying these associations once an cross-sectional, and future longitudinal was observed in the meta-analysis by individual reaches the threshold of a and intervention research will need to Ekelund et al. (9). Finally, further work is diagnosis of metabolic disease. Finally, investigate the impact of differences needed to understand the biological the study included both sexes, which is and/or changes in SB on metabolic risk. differences between physical inactivity Figure 1—Diagram of study participant activity (10), with the dashed slice denoting much lower, typical MVPA levels. SB and LPA are tightly correlated and are related to risk of developing metabolic syndrome, with high SB and low LPA associated with greatest risk. care.diabetesjournals.org Whipple, Regensteiner, and Bergouignan 19 and SB. By better delineating the com- 6. Edwardson CL, Gorely T, Davies MJ, et al. sedentary behaviors in large epidemiologic studies. plex interrelationships between SB, LPA, Association of sedentary behaviour with meta- Exerc Sport Sci Rev 2012;40:118–126 and MVPA as well as the potential mech- bolic syndrome: a meta-analysis. PLoS One 2012; 17. Chastin SFM, Palarea-Albaladejo J, Dontje 7:3–7 ML, Skelton DA. Combined effects of time spent anisms linking SB to cardiometabolic risk 7. Biswas A, Oh PI, Faulkner GE, et al. Sedentary in physical activity, sedentary behaviors and (25), we can move toward more com- time and its association with risk for disease sleep on obesity and cardio-metabolic health prehensive public health guidelines that incidence, mortality, and hospitalization in markers: a novel compositional data analysis discuss SB recommendations for specific adults a systematic review and meta-analysis. approach.