The effect of physical activity on serum IL-6 and vaspin levels in late elementary school children

[Purpose]

This study investigates the effects of physical activity on serum IL-6 and vaspin in late elementary school children.

[Methods]

Those who (n = 220) completed the 7-day physical activity monitoring underwent a second round of measurements including body fat, serum glucose and insulin, and serum IL-6 and vaspin. One way ANOVAs followed by LSD post hoc tests were used to test for significant differences in dependent variables across incremental physical activity levels at p=0.05. Multivariate stepwise linear regression analyses were used to determine significant predictors for serum IL-6 and vaspin levels at p=0.05.

[Results]

The results showed significant inverse linear trends for body fat parameters across incremental physical activity levels (from low to high); the lower the body fat, the higher the physical activity levels. On the other hand, there were no significant linear trends for insulin resistance markers or dietary intake across incremental physical activity levels. Multiple stepwise linear regression analyses were used to determine significant predictors for individual variations in serum IL-6 and vaspin in the study population. We found that body mass index (p=0.002) and low- and moderate-intensity physical activities (p=0.002 and p=0.0045, respectively) were significant determinants of serum IL-6. In addition, low- and moderate-intensity physical activities (p=0.01 & p=0.022, respectively) were significant determinants of serum vaspin levels in this study population.

[Conclusion]

In summary, the findings of the current study suggest that promotion of physical activity along with a healthy diet should be key components of lifestyle interventions to improve serum cytokine profiles associated with insulin resistance syndrome in late elementary school children.     

Fatness, fitness, and insulin sensitivity among 7- to 9-year-old children

Objective: The purpose of this study was to examine the relationships among fatness and aerobic fitness on indices of insulin resistance and sensitivity in children. Research Design and Methods: A total of 375 children (193 girls and 182 boys) 7 to 9 years of age were categorized by weight as normal‐weight, overweight, or obese and by aerobic fitness based on a submaximal physical working capacity test (PWC). Fasting blood glucose (GLU) and insulin (INS) were used to calculate various indices of insulin sensitivity (GLU/INS), the homeostasis model assessment (HOMA), and the quantitative insulin sensitivity check index (QUICKI). Surrogate measures of pancreatic β cell function included the insulinogenic index (INS/GLU) and the HOMA estimate of pancreatic β‐cell function (HOMA %B). Results: Insulin sensitivity and secretion variables were significantly different between the normal‐weight children and the overweight and obese subjects. Fasting insulin (FI), HOMA, QUICKI, and INS/GLU were significantly different between the overweight and obese subjects. Likewise, the high fitness group possessed a better insulin sensitivity profile. In general, the normal‐weight–high fit group possessed the best insulin sensitivity profile and the obese‐unfit group possessed the worst insulin sensitivity profile. Several significant differences existed among the six fat‐fit groups. Of particular note are the differences within BMI groups by fitness level and the comparison of values between the normal‐weight–unfit subjects and the overweight and obese subjects with high fitness. Conclusions: The results indicate that aerobic fitness attenuates the difference in insulin sensitivity within BMI categories, thus emphasizing the role of fitness even among overweight and obese children.     

Insulin Sensitivity,Cardiorespiratory Fitness,and Physical Activity in Overweight Hispanic Youth

Objective: To determine whether cardiorespiratory fitness and/or physical activity (PA) were related to measures of insulin sensitivity and secretion independent of body composition in overweight Hispanic children. Research Methods and Procedures: Ninety‐five Hispanic children (n = 55 boys; n = 40 girls; 8 to 13 years old) participated in this investigation. The frequently sampled intravenous glucose tolerance test was used to determine the insulin sensitivity index (SI), the acute insulin response, and the disposition index. Cardiorespiratory fitness [maximal oxygen uptake (Vo_2max)] was evaluated using a treadmill protocol, and PA was determined by an interviewer‐administered questionnaire. Body composition was measured using DXA. Results: Unadjusted correlations indicated that Vo_2max (milliliters of O₂ per minute) was negatively related to SI (r = ?0.46, p < 0.05) and disposition index (r = ?0.31, p < 0.05) and positively associated with fasting insulin (r = 0.29, p < 0.05), but these relationships were no longer significant once gender, Tanner stage, fat mass, and soft lean tissue mass were included as covariates (all p > 0.05). Multivariate linear regression analysis showed that body fat mass explained 53% of the variance in SI and that Vo_2max (milliliters of O₂ per minute) was not independently related to SI. Cardiorespiratory fitness was positively related to both fat mass (r = 0.43, p < 0.001) and soft lean tissue mass (r = 0.89, p < 0.001). PA was not related to any measure of insulin sensitivity and secretion. Discussion: Cardiorespiratory fitness, as determined by Vo_2max (milliliters of O₂ per minute), was not independently related to insulin sensitivity or secretion, suggesting that Vo_2max influences insulin dynamics indirectly through fat mass.     

Correlates of life course physical activity in participants of the Baltimore longitudinal study of aging

Physical activity is consistently associated with better health and longer life spans. However, the extent to which length and intensity of exercise across the life course impact health outcomes relative to current activity is undefined. Participants of the Baltimore Longitudinal Study of Aging were asked to categorize their level of physical activity in each decade of life from adolescence to the current decade. In linear mixed effects models, self-reported past levels of physical activity were significantly associated with activity assessed at study visits in the corresponding decade of life either by questionnaire or accelerometry. A pattern of life course physical activity (LCPA) derived by ranking participants on reported activity intensity across multiple decades was consistent with the trajectories of activity estimated from standard physical activity questionnaires assessed at prior study visits. In multivariable linear regression models LCPA was associated with clinical characteristics, measures of body composition and indicators of physical performance independent of current physical activity. After adjustment for minutes of high intensity exercise, LCPA remained significantly associated with peak VO₂, fasting glucose, thigh muscle area and density, abdominal subcutaneous fat, usual gait speed, lower extremity performance, and multimorbidity (all p < 0.01) at the index visit. The observed associations suggest that an estimate of physical activity across decades provides complementary information to information on current activity and reemphasizes the importance of consistently engaging in physical activity over the life course.     

Effect of a 12-week non-contact exercise intervention on body composition and health-related physical fitness in adults: a pilot test

[Purpose] The purpose of this study was to evaluate the effects of a 12-week non-contact exercise intervention on body composition and health-related physical fitness in adults.[Methods] One hundred adults were initially enrolled; however, ninety-seven participants (men: n = 41, women: n = 56) completed the study. The non-contact exercise was performed for 12 weeks using a smart tracker (Charge 4, Fitbit, USA) and mobile phone applications. The non-contact exercise program included resistance, aerobic, and flexibility exercises.[Results] The results showed that percent body fat (F=4.993, p=.016, η_p²=.049), fat-free mass (F=4.690, p=.024, η_p²=.047), and skeletal muscle mass (F=5.623, p=.004, η_p²=.055) significantly changed during the intervention period. Further, significant increases were seen in hand grip strength (F=12.167, p<.001, η_p²=.112), sit-and-reach (F=20.497, p<.001, η_p²=.176), sit-ups (F=42.107, p<.001, η_p²=.305), and VO_2max (F=4.311, p=.037, η_p²=.043).[Conclusion] Our findings suggest that 12 weeks of non-contact exercise improves body composition and health-related physical fitness. Wearable technologies encourage individuals to modify their lifestyles by increasing physical activity and achieving the goal of maintaining health conditions among adults.     

Poor physical fitness is independently associated with mild cognitive impairment in elderly Koreans

The purpose of this study was to investigate the association between physical fitness and mild cognitive impairment (MCI) in elderly Koreans. This was a cross-sectional study that involved 134 men and 299 women aged 65 to 88 years. Six senior fitness tests were used as independent variables: 30 s chair stand for lower body strength, arm curl for upper body strength, chair-sit-and-reach for lower body flexibility, back scratch for upper body flexibility, 8-ft up-and-go for agility/dynamic balance, and 2-min walk for aerobic endurance. Global cognitive function was assessed using the Korean version of the Mini-Mental State Examination (MMSE). Potential covariates such as age, education levels, blood lipids, and insulin resistance (IR) markers were also assessed. Compared to individuals without MMSE-based MCI, individuals with MMSE-based MCI had poor physical fitness based on the senior fitness test (SFT). There were significant positive trends observed for education level (p=0.001) and MMSE score (p<0.001) across incremental levels of physical fitness in this study population. Individuals with moderate (OR=0.341, p=0.006) and high (OR=0.271, p=0.007) physical fitness based on a composite score of the SFT measures were less likely to have MMSE-based MCI than individuals with low physical fitness (referent, OR=1). The strength of the association between moderate (OR=0.377, p=0.038) or high (OR=0.282, p=0.050) physical fitness and MMSE-based MCI was somewhat attenuated but remained statistically significant even after adjustment for the measured compounding factors. We found that poor physical fitness was independently associated with MMSE-based MCI in elderly Koreans.     

Cardiorespiratory fitness in youth: relationship to insulin sensitivity and beta-cell function

Objective: We examined whether the relationship between cardiorespiratory fitness (CRF) and insulin sensitivity (IS)/secretion is independent of adiposity in healthy African‐American (n = 65) and white (n = 57) youth. Research Methods and Procedures: IS and β‐cell function were evaluated by a 3‐hour hyperinsulinemic‐euglycemic and a 2‐hour hyperglycemic (12.5 mM) clamp, respectively. Total fat was measured by DXA and abdominal fat with computed tomography. CRF (peak volume of oxygen) was measured using a graded maximal treadmill test. Results: Independent of race, CRF was inversely (p < 0.05) related to total and abdominal fat, fasting insulin and first phase insulin secretion, and positively (p < 0.05) related to IS. When subjects were categorized into low (≤50th) and high (>50th) CRF groups, IS was significantly (p < 0.05) higher in the high compared with the low CRF group independently of race. Furthermore, first and second phase insulin secretion were lower (p < 0.05) in the high CRF group in comparison with the low CRF group in both races. However, in multiple regression analyses CRF was not (p > 0.05) an independent predictor of IS and acute insulin secretion after accounting for total adiposity. Discussion: Our findings demonstrate that low CRF is associated with decreased IS compensated by higher insulin secretion in both African‐American and white youth. However, this relationship disappears after adjusting for differences in adiposity, suggesting that the association between fitness and IS is mediated, at least in part, through fatness.     

12周基础性抗载荷训练对某航空学校飞行学生体能影响研究*

目的: 观察12周基础性抗载荷体能训练对某航空学校学生身体成分、力量素质及体力活动水平的影响,探讨其在飞行员体能训练应用的可能性。方法: 以某航空学校飞行学生为研究对象,抽取自愿参加研究的男性学生37人,随机分为对照组(19人)和试验组(18人),试验组进行12周的基础性抗载荷体能训练,包括高强度间歇训练(HIIT)和高强度力量训练联合干预,测试训练前后两组学生身体成分、力量素质及体力活动水平变化。结果: 与对照组相比,试验组去脂体重和肌肉量,下肢蹬伸力量和躯干等长收缩、伸展力量,体力活动能量消耗和活动步数均显著增加(P＜0.05)。结论: 12周基础性抗载荷训练能促进飞行学生抗载荷关键素质提高,可作为飞行员体能训练内容尝试应用。     

The association between an objective measure of physical activity and weight status in preschoolers

Objective: Our objective was to determine the association between physical activity and BMI among racially diverse low‐income preschoolers. Research Methods and Procedures: This was a cross‐sectional study of 2‐ to 5‐year‐olds (n = 56) enrolled in Massachusetts Special Supplemental Nutrition Program for Women, Infants & Children (WIC). Physical activity was measured for 7 consecutive days with an accelerometer. Height and weight were obtained from WIC records, and BMI‐for‐age percentiles were calculated based on the Centers for Disease Control and Prevention's (CDC) 2000 Growth Charts. At‐risk‐for‐overweight (BMI‐for‐age of ≥85th to <95th percentile) and overweight (BMI‐for‐age ≥95th percentile) groups were combined and referred to as overweight. Final analysis inclusion criteria were: completion of 4.5 days of activity assessment and anthropometric data obtained within 90 and 120 days of the activity assessment for children ages 24 to 35.99 and 36 to 59.99 months, respectively. Results: Overweight children had significantly lower mean daily very vigorous minutes (VVM) (2.6 mins vs. 4.6 mins, p < 0.05) and lower very active minutes (VAM) [i.e., sum of vigorous minutes (VM) and VVM] per day (22.9 mins vs. 32.1 mins, p < 0.05) than children who were not overweight. Daily VVM [odds ratio (OR) = 0.68; 95% confidence interval (CI), 0.49 to 0.96], VM (OR = 0.94; CI, 0.88 to 1.00), and VAM (OR = 0.94; 95% CI, 0.89 to 1.00) were all associated with significantly lower odds of being overweight. Discussion: This study suggests that, in a diverse group of preschoolers, vigorous and very vigorous activity are associated with lower odds of overweight. However, these findings require corroboration in a diverse sample of preschoolers using a longitudinal design.     

Bidirectional selection for body mass and correlated response of pyrethroid resistance and fitness in Sitophilus zeamais

Responses to artificial selection on body mass in the maize weevil Sitophilus zeamais (Coleoptera: Curculionidae) were investigated to determine whether changes in body mass are associated with insecticide susceptibility, rate of population growth, and metabolic rate. Two strains of the maize weevil differing in susceptibility to pyrethroid insecticides were subjected to bidirectional selection on body mass. The susceptible strain responded to selection resulting in individuals with lower or higher body mass, but the resistant strain responded significantly only to selection for lower body mass. The resistant strain selected for low body mass increased its level of deltamethrin resistance in 44 × . In contrast, selection for low body mass in the susceptible parental strain led to increased deltamethrin susceptibility (50 × ) and selection for high body mass increased deltamethrin resistance (4 × ). Thus, the correlated response of insecticide resistance to selection for body mass differed between strains, a likely consequence of their distinct genetic background. Regardless, body mass was positively correlated with fitness (reproductive output) (r = 0.79; P < 0.001), while such correlation with respiration rate was significant only at P = 0.07 (r = 0.44). Therefore, the association between body mass and deltamethrin resistance is population‐dependent in the maize weevil, and the confluence of deltamethrin resistance and high body mass in a given strain will likely favour its energy metabolism and lead to the mitigation of fitness costs usually associated with insecticide resistance. The genetic background and selection history of insecticide resistant populations should not be neglected since they may favour the confluence of insecticide resistance with mitigation mechanisms of its associated fitness costs limiting the tactics available to their management.     

Correlates of adherence to a physical activity program in young African-American girls

Objective: The goal was to identify correlates of adherence to a structured physical activity (PA) program. Research Methods and Procedures: Subjects were 136 8‐ to 12‐year‐old African‐American girls. Potential correlates at baseline were: 1) fitness index (FI: % body fat from DXA and cardiovascular fitness from treadmill test), and 2) self‐esteem, anxiety, attitude to school and teachers, relationship with parents, and interpersonal relations (Behavioral Assessment System for Children). The 10‐month PA program included 80 minutes of PA offered 5 days/wk. Regression tree classification was used to model attendance. Results: Six splits occurred (34% total variance explained). Less anxious subjects attended more often than highly anxious subjects (3 days/wk vs. 1.5 days/wk) did. Subjects with a healthier FI attended more often than those with a less healthy FI (3 days/wk vs. 0.5 days/wk) did. Younger subjects attended more often than older ones (3 days/wk vs. 2.5 days/wk) did. The next two splits were again with anxiety (3.5 days/wk vs. 3 days/wk) and FI (3 days/wk vs. 2.5 days/wk). Finally, subjects with higher levels of self‐esteem attended more often than those with lower levels (3.5 days/wk vs. 2 days/wk) did. Discussion: Subjects who were self‐confident, younger, fitter, and less anxious were more likely to participate regularly. This suggests that children who may be more likely to benefit from a PA program are less likely to participate. To enhance participation in PA programs, especially in older African‐American girls: 1) psychological concerns should be identified and addressed before enrollment, and 2) programs should be designed to be appealing to children of all fitness levels.     

应激对机体脑体功能的影响及其生物学机制初探

目的：探讨应激对机体脑体功能的损伤效应及其生物学机制,为应激损伤防护措施的制订提供科学依据。方法：采用束缚应激模型,观察模型动物认知功能、体能、海马LTP、血浆糖皮质激素、心电图、心肌组织结构等指标的变化。结果：应激动物学习记忆能力和运动耐力明显下降,血浆糖皮质激素水平显著升高,海马LTP诱发受到抑制,心电图异常改变,心功能紊乱,心肌组织结构出现病理损伤,心肌细胞凋亡率增加,心肌组织Hsp70表达水平随应激强度增加而逐渐降低。结论：应激诱导机体神经一内分泌功能紊乱,进而导致机体脑体功能损伤。     

小菜蛾对阿维菌素的抗性遗传方式 和相对适合度研究

就小菜蛾Plutella xylostella对阿维菌素的抗性遗传方式和抗性品系的相对适合度进行了研究。室内选育的阿维菌素抗性品系与同源的敏感品系杂交、F₁代自交、F₁代与亲本回交,结果表明：杂交后的显性度（D）分别为-0.64和-0.52,说明小菜蛾对阿维菌素的抗性是常染色体、不完全隐性遗传;χ²检验证实,可能是多基因控制的抗性遗传。杂交F₁代乙酰胆碱酯酶（AChE）、羧酸酯酶（CarE）和谷胱甘肽转移酶（GST）活性比抗性亲本有所降低,F2代及回交后代三种酶的活性继续降低。种群适合度研究表明,抗性品系相对于敏感品系有0.84的适合度。     

Roles of mitochondrial fragmentation and reactive oxygen species in mitochondrial dysfunction and myocardial insulin resistance

Purpose

Evidence suggests an association between aberrant mitochondrial dynamics and cardiac diseases. Because myocardial metabolic deficiency caused by insulin resistance plays a crucial role in heart disease, we investigated the role of dynamin-related protein-1 (DRP1; a mitochondrial fission protein) in the pathogenesis of myocardial insulin resistance.

Methods and Results

DRP1-expressing H9c2 myocytes, which had fragmented mitochondria with mitochondrial membrane potential (ΔΨ_m) depolarization, exhibited attenuated insulin signaling and 2-deoxy-d-glucose (2-DG) uptake, indicating insulin resistance. Treatment of the DRP1-expressing myocytes with Mn(III)tetrakis(1-methyl-4-pyridyl)porphyrin pentachloride (TMPyP) significantly improved insulin resistance and mitochondrial dysfunction. When myocytes were exposed to hydrogen peroxide (H₂O₂), they increased DRP1 expression and mitochondrial fragmentation, resulting in ΔΨ_m depolarization and insulin resistance. When DRP1 was suppressed by siRNA, H₂O₂-induced mitochondrial dysfunction and insulin resistance were restored. Our results suggest that a mutual enhancement between DRP1 and reactive oxygen species could induce mitochondrial dysfunction and myocardial insulin resistance. In palmitate-induced insulin-resistant myocytes, neither DRP1-suppression nor TMPyP restored the ΔΨ_m depolarization and impaired 2-DG uptake, however they improved insulin signaling.

Conclusions

A mutual enhancement between DRP1 and ROS could promote mitochondrial dysfunction and inhibition of insulin signal transduction. However, other mechanisms, including lipid metabolite-induced mitochondrial dysfunction, may be involved in palmitate-induced insulin resistance.     

Triaxial accelerometry for assessment of physical activity in young children

Objective: The purpose of the present study was to derive linear and non‐linear regression equations that estimate energy expenditure (EE) from triaxial accelerometer counts that can be used to quantitate activity in young children. We are unaware of any data regarding the validity of triaxial accelerometry for assessment of physical activity intensity in this age group. Research Methods and Procedures: EE for 27 girls and boys (6.0 ± 0.3 years) was assessed for nine activities (lying down, watching a video while sitting and standing, line drawing for coloring‐in, playing blocks, walking, stair climbing, ball toss, and running) using indirect calorimetry and was then estimated using a triaxial accelerometer (ActivTracer, GMS). Results: Significant correlations were observed between synthetic (synthesized tri‐axes as the vector), vertical, and horizontal accelerometer counts and EE for all activities (0.878 to 0.932 for EE). However, linear and non‐linear regression equations underestimated EE by >30% for stair climbing (up and down) and performing a ball toss. Therefore, linear and non‐linear regression equations were calculated for all activities except these two activities, and then evaluated for all activities. Linear and non‐linear regression equations using combined vertical and horizontal acceleration counts, synthetic counts, and horizontal counts demonstrated a better relationship between accelerometer counts and EE than did regression equations using vertical acceleration counts. Adjustment of the predicted value by the regression equations using the vertical/horizontal counts ratio improved the overestimation of EE for performing a ball toss. Discussion: The results suggest that triaxial accelerometry is a good tool for assessing daily EE in young children.     

Exercise ameliorates insulin resistance and improves ASK1-mediated insulin signalling in obese rats

Increasing evidence reveals that physical exercise is an efficient therapeutical approach in the treatment of insulin resistance (IR) and related metabolic diseases. However, the potential beneficial effects of exercise on insulin resistance and its underlying mechanisms remain unclear. Recent findings elucidated the negative role of ASK1 in repressing the glucose uptake through JNK1-IRS1-Akt signalling in liver. Thus, a detailed investigation of the effect of ASK1-mediated insulin signalling on exercise-mediated improvement of insulin sensitivity and its underlying mechanism was implemented in this study. Using a high-fat diet-induced IR rat model of chronic or acute swimming exercise training, we here showed that body weight and visceral fat mass were significantly reduced after chronic exercise. Moreover, chronic exercise reduced serum FFAs levels and hepatic triglyceride content. Both chronic and acute exercise promoted glucose tolerance and insulin sensitivity. Meanwhile, both chronic and acute exercise decreased ASK1 phosphorylation and improved JNK1-IRS1-Akt signalling. Furthermore, exercise training decreased CFLAR, CREG and TRAF1 protein levels in liver of obese rats, which are positive regulator of ASK1 activity. These results suggested that swimming exercise demonstrated to be an effective ameliorator of IR through the regulation of ASK1-mediated insulin signalling and therefore, could present a prospective therapeutic mean towards the treatment of IR and several metabolic diseases based on IR, containing NAFLD and type Ⅱ diabetes.