Page 78 - 《运动与健康科学》(英文)2024年第2期

TaggedFigure
TaggedEnd200 J. Liao et al.

Fig. 1. Joint association of daily sitting time and leisure-time physical activity with total body fat percentage among U.S. adults by sex, NHANES 20112018.
Joint association of daily sitting time (h/day) and leisure-time physical activity (min/week) with total fat percentage within each subgroup: (A) male and (B)
female. Estimates were adjusted for age (year), sex (male or female), race (non-Hispanic White, non-Hispanic Black, Hispanic, or other), educational attainment
(less than high school, high school graduate, or above high school), family poverty ratio (<1.3, 1.3 to <3.5, or 3.5), smoking status (never, former, or current),
alcohol use (never, former, or current), total energy intake and Healthy Eating Index-2015, hypertension (yes or no), hypercholesterolemia (yes or no), history of
diabetes (yes or no), history of CVD (yes or no), history of cancer (yes or no), and depression (yes or no). 95%CI = 95% confidence interval; CVD = cardiovascular
disease; NHANES = National Health and Nutrition Examination Survey.TaggedEnd

fact that sedentary behavior has been associated with increased to decreased energy expenditure. 42 Previous studies have indi-
all-cause mortality risk among adults, physical activity could cated that breaking prolonged sedentary behaviors could lead to
6 16,43
offset the detrimental effect of prolonged sitting. That is to weight loss. Localized accumulation of adipose tissue in the
say, achieving 150 or more min/week of LTPA could attenuate abdominal area (trunk) has been reported to be the best correlate
44
the elevated all-cause mortality risk due to prolonged sitting to of dyslipidemia seen in the metabolic syndrome, and this link
null. The joint association of sitting and physical activity has may be explained by excess free fatty acid release, impaired
been determined for other health outcomes, including incident carbohydrate oxidation and muscle glucose storage, reduced
45
CVD, 39 cardiometabolic health, 40 all-cause mortality, 41 and hepatic insulin clearance, and elevated triglycerides. As phys-
7
cancer survival. Using a nationally representative sample of ical activity is a major determinant of body composition
U.S. adults, the present study systematically evaluated the (reflected by fat-free mass) and only partly contributes to accu-
independent and joint associations of total sitting time and mulation of fat in aging adults, 46 sedentary behaviors may also
LTPA with body fat. A notable doseresponse association play an important role in fat accumulation. Other hypotheses
between total sitting time and total and trunk fat was observed, suggest that sedentariness may involve specific molecular
and this association was exhibited not only in adults engaging responses, which contribute to poor lipid metabolism through
in fewer than 150 min/week of LTPA, but also in those suppressing skeletal muscle lipoprotein lipase activity. 47 If
these associations are causal, then it is possible that prolonged
achieving 150 min/week of LTPA.TaggedEnd
TaggedPThe mechanisms underlying the associations are largely sitting time might be a critical driver of metabolic derangement,
unknown. At the lower end of the bodily movement continuum, which manifests in excess accumulation of fat in the abdominal
large amounts of sedentary time and insufficient physical area (mainly as visceral fat). Also, there is a possible bidirec-
activity involve the reduction of muscle activation, which leads tional relationship between sitting time and physical inactivity