The purpose of this study was to summarize the associations of physical activity (PA) and sedentary time (SED) with metabolic health and examine the effects of time reallocation on metabolic health in adolescents using accelerometer data. A literature search was conducted using PubMed, ScienceDirect, Web of Science, Cochran Library, and Google Scholar, and 27 articles were reviewed. Recent research generally confirms the associations of PA and SED with metabolic health. High PA levels and low SED levels had a positive relationship with metabolic health. Moreover, reallocating 10 min of daily SED to PA was associated with better metabolic health indicators. These results were stronger for moderate-to-vigorous physical activity than for light intensity PA. Thus, efforts to convert SED into PA of at least moderate intensity appear to be an effective strategy to prevent metabolic disease development in children and adolescents. However, some of the associations between PA and metabolic health indicators were inconsistent, depending on age, obesity degree, and PA intensity. Additionally, various accelerometer data collection and processing criteria impact the interpretation of the results. Therefore, consistent accelerometer data collection and analysis methods are needed in future studies. Further, intervention studies are required to verify the causality and effectiveness of the isotemporal substitution model.

OBJECTIVES: The study aimed to examine whether simultaneously meeting the combined guidelines of accelerometer-assessed moderate to vigorous physical activity (MVPA) and self-reported muscle-strengthening activity (MSA) was associated with lower odds of metabolic syndrome (MetS) than meeting neither or 1 of the guidelines among the Koreans.METHODS: This cross-sectional analysis included 1,355 participants from the Korea National Health and Nutrition Examination Survey (2014-2015). Logistic regression was used to analyze the associations across groups of MVPA-MSA guideline adherence (meeting neither [reference]; meeting MVPA only; meeting MSA only; meeting both MVPS and MSA) with MetS components (abdominal obesity, hypertriglyceridemia, low high-density lipoprotein cholesterol [HDL-C], hypertension, and hyperglycemia). The odds ratios (ORs) were adjusted for covariates (e.g., sex, age, body mass index, and accelerometer wearing time).RESULTS: MSA only significantly reduced the OR for abdominal obesity (OR, 0.34; 95% confidence interval [CI], 0.13 to 0.91). Meeting both MVPA and MSA reduced the OR for hypertriglyceridemia (OR, 0.59; 95% CI, 0.39 to 0.88) and low HDL-C (OR, 0.46; 95% CI, 0.31 to 0.68). Compared to meeting neither, MVPA only (OR, 0.63; 95% CI, 0.44 to 0.89) and both MVPA and MSA (OR, 0.46; 95% CI, 0.28 to 0.76) significantly reduced the OR for MetS.CONCLUSIONS: Combined MVPA-MSA was more beneficially associated with MetS prevalence than MVPA only and MSA only. Considering that more than 85% of Korean adults do not meet both the MVPA and MSA guidelines, public health actions to promote adherence should be supported.

PURPOSE: The purpose of this study was to examine the association between objectively measured physical activity and metabolic syndrome in Korean adults and older adults.METHODS: A total of 2,191 adults and older adults from the Korea National Health and Nutrition Examination Survey from 2014 to 2017 were analyzed. Participants were categorized into three groups (‘Inactive’, ‘Active’, ‘Highly active’) according to physical activity guidelines. A chi-square test was performed to confirm whether the physical activity guidelines were met according to metabolic syndrome and the difference between metabolic syndrome according to age group. Logistic regression was used to predict the relationship between physical activity and metabolic syndrome.RESULTS: The prevalence of metabolic syndrome differed according to whether physical activity guidelines were met in older adults, and the prevalence of metabolic syndrome and its risk factors varied according to age group. Compared to the Inactive group, the odds ratios (OR) for metabolic syndrome were 0.73 (95% confidence interval [CI]: 0.56-0.95) and 0.65 (95% CI: 0.47-0.88) in adults in the Active and Highly active groups, respectively; and 0.46 (95% CI: 0.28-0.78) and 0.39 (95% CI: 0.22-0.69) in older adults in the Active and Highly active groups, respectively.CONCLUSIONS: As the level of physical activity increased, the OR of having metabolic syndrome and its risk factors decreased: this relationship was stronger in older adults than in adults. Therefore, physical activity guidelines should be met to prevent and manage metabolic syndrome.

Hak Kyun Kim, Yeon Soo Kim, Hoyong Sung, Jungjoon Lim, Joonsik Kim, Harim Choi. KJSM 2021;39:181-7. https://doi.org/10.5763/kjsm.2021.39.4.181

OBJECTIVES: The aim of this study was to identify the stepping cadence patterns in Korean adults by using objectively measured accelerometer data to analyze the time spent in each cadence category by sex and age.METHODS: During the 2014-2015 Korean National Health and Nutrition Examination Survey, 1,703 males and females aged 19-64 years provided at least 1 valid day of data (wearing an accelerometer ≥ 10 hr/d). The mean cumulative time and percentage per day in 8 cadence categories (0, 1-19, 20-29, 30-59, 60-79, 80-99, 100-119, and ≥ 120 steps/min) by sex and age group were calculated.RESULTS: Cumulative time and percentage per day decreased across the incremental cadence categories. Participants spent 360.08± 2.56 min/d in the non-movement cadence category and 361.50± 2.28 min/d in the incidental movement cadence category. However, they spent only about 18.1 min/d (2.1%) at ≥ 100 steps/min. Males spent significantly more time in the cadence categories of sporadic movement, purposeful steps, slow walking, and medium walking, but the other categories, except for brisk walking, had higher values in females (p< 0.001). The older age group spent less time in non-movement cadence categories, and the youngest and oldest groups spent more time at a higher cadence (≥ 100 steps/min) than the other age groups. Similar patterns were found in a subgroup analysis by sex.CONCLUSIONS: Korean adults spent most of their time at a low cadence and only a few minutes at a high cadence (≥100 steps/min); this trend was consistent across sex and age groups.

Jungjun Lim, Hoyong Sung, Joon-Sik Kim, Geonhui Kim, Jungwoon Kim, Yeonsoo Kim. KJSM 2022;40:189-96. https://doi.org/10.5763/kjsm.2022.40.3.189