Cardiorespiratory Fitness, Physical Activity, and Insulin Resistance in Children

Poor Eating Habits and Low Physical Activity Contribute to Weight Excess and Increase Cardiometabolic Risk in Adolescents Practicing Soccer as a Recreational Sport

BACKGROUND

Monitoring anthropometry, dietary intake, and physical activity (PA) is essential to prevent/counteract childhood obesity. This study examined dietary intake, PA, and anthropometric characteristics in young boys practicing soccer as a recreational sport.

METHODS

A cross-sectional study included 226 boys aged 8 to 13 years participating in soccer as a recreational activity in football academies located in Tunis, Tunisia. Anthropometric measures allowed the calculation of body mass index, fat mass, and peak height velocity as markers of biological maturity. A three-day food record and a food frequency questionnaire estimated nutrient intake and eating habits. The International Physical Activity Questionnaire (IPAQ) was used to estimate the PA level of the participants.

RESULTS

It was found that a high percentage of the children had excess weight (54%) and excess fat mass (47%). The total energy, carbohydrate, and saturated fat intake of the children exceeded the recommended levels by approximately 10%, 15%, and 30%, respectively. However, the intake of unsaturated fat was below the estimated requirements, particularly in obese children. In addition to the unbalanced macronutrient intake, the children also showed an insufficient intake of many essential micronutrients. Around 60% to 70% of the children in all three groups had a low intake of magnesium, n-3 polyunsaturated fatty acids (PUFA), and vitamins B9, B12, and D. Moreover, 20% to 35% of the children in the three groups had an insufficient intake of vitamins A and C. Insufficient vitamin E intake was found in 63% of obese children and 35% of non-obese children. It was observed that the PA level was lower in the overweight/obese group compared to the normal-weight group (p < 0.005). More than three-quarters of overweight/obese children had low PA levels, about 20% were moderately active, and only 1 to 2% were highly active. Conversely, normal-weight children showed moderate to high PA levels.

CONCLUSIONS

Poor eating behavior, an unbalanced diet, and a low PA level are prevalent in Tunisian boys practicing recreational sports. Such a combination is responsible for a disparity between energy intake and expenditure, contributing to weight excess and increased cardiometabolic risk. The study findings provide meaningful information for practitioners and authorities on applying a balanced diet and adequate PA to prevent and fight against obesity and improve cardiometabolic health in youth.

Role of remnant cholesterol in the relationship between physical activity and diabetes mellitus: an intermediary analysis

Objective

The purpose of this investigation was to evaluate the potential link between physical activity (PA) and the heightened susceptibility to diabetes mellitus (DM), by examining whether remnant cholesterol (RC) might act as a mediator in this correlation.

Methods

The research utilized data from the National Health and Nutrition Examination Survey, spanning from 2005 to 2018. Various statistical analyses were conducted for continuous and categorical variables, including the t-test, ANOVA, and χ2 test. Logistic regression was employed to analyze the association between PA and DM across three distinct models. Mediation analysis was also conducted to assess the potential mediation effects of RC.

Results

The study encompassed a total of 9,149 participants, and it was observed that individuals with DM exhibited lower levels of PA. Furthermore, PA levels were found to be associated with all participant characteristics except poverty income ratio, fasting blood glucose, and HOMA-IR (p < 0.05). After adjusting for covariates (Model 3), individuals with high PA levels demonstrated a decreased likelihood of developing DM compared to those in the low PA group (OR: 0.73, 95%CI: 0.54-0.99). A significant dose-response relationship was identified (p < 0.05). No interaction between PA and RC in relation to DM risk was detected, and RC was found to serve as a mediator in the connection between PA and DM. After considering covariates, the mediating effect of RC between PA and DM weakens.

Discussion

Our findings suggest that higher levels of PA are linked to a reduced risk of DM in U.S. adults, with RC likely playing a mediating role.

Exercise performance in children and adolescents with cystic fibrosis with and without abnormal glucose tolerance: a single center cross-sectional study

BACKGROUND

Abnormal glucose tolerance (AGT) in cystic fibrosis (CF) affects lung function and clinical parameters, including aerobic fitness. However, its effects on physical activity level (PAL), anaerobic power (AP), and muscle strength (MS) in children and adolescents are unknown.

PURPOSE

To investigate aerobic fitness, PAL, AP, and MS in pediatric patients with mild-to-moderate CF and AGT.

METHODS

The study included children and adolescents with CF aged 10-18 years. Participants underwent a pulmonary function test, quadriceps, and handgrip MS measurement, vertical jump test to assess AP, and six-minute walk test (6MWT) to assess aerobic fitness. Bouchard's Three-Day Physical Activity record was used to determine PAL.

RESULTS

Height z-score (p = .006), 6MWT (p = .024), handgrip (p = .028), quadriceps MS (p = .044), and AP (p = .036) were significantly lower in AGT (n = 21) than normal glucose tolerance (NGT) (n = 19). In the AGT group, glycosylated hemoglobin (HbA1c) was significantly associated with forced expiratory volume in one second (FEV1) (p = .046). 6MWT distance (6MWD) was associated with height (p = .008), FEV1 (p = .001), forced vital capacity (FVC) (p = .001), forced expiratory flow from 25% to 75% (FEF25-75%) (p = .030), handgrip MS (p = .012), and PAL (p = .034). After adjusting for height and FEV1, the groups had similar 6MWD, MS, and AP (p > .05); also, insulin was associated with MS and AP but not with 6MWT or quadriceps MS.

CONCLUSION

Measures of aerobic fitness, MS, and AP are lower in AGT, but after adjusting for height and FEV1, aerobic fitness, MS, and AP do not show substantial differences. Insulin sensitivity and resistance are associated with MS and AP.

Which indices of cardiorespiratory fitness are more strongly associated with brain health in children with overweight/obesity?

PURPOSE

To compare the strength of associations between different indices of cardiorespiratory fitness (CRF) and brain health outcomes in children with overweight/obesity.

METHODS

Participants were 100 children aged 8-11 years. CRF was assessed using treadmill exercise test (peak oxygen uptake [V̇O2peak ], treadmill time, and V̇O2 at ventilatory threshold) and 20-metre shuttle run test (20mSRT, laps, running speed, estimated V̇O2peak using the equations by Léger et al., Mahar et al., and Matsuzaka et al.). Intelligence, executive functions, and academic performance were assessed using validated methods. Total gray matter and hippocampal volumes were assessed using structural MRI.

RESULTS

V̇O2peak /body mass (β = 0.18, 95% CI = 0.01-0.35) and treadmill time (β = 0.18-0.21, 95% CI = 0.01-0.39) were positively associated with gray matter volume. 20mSRT laps were positively associated with executive functions (β = 0.255, 95% CI = 0.089-0.421) and academic performance (β = 0.199-0.255, 95% CI = 0.006-0.421), and the running speed was positively associated with executive functions (β = 0.203, 95% CI = 0.039-0.367). Estimated V̇O2peak/Léger et al. was positively associated with intelligence, executive functions, academic performance, and gray matter volume (β = 0.205-0.282, 95% CI = 0.013-0.500). Estimated V̇O2peak/Mahar et al. and V̇O2peak/Matsuzaka et al. (speed) were positively associated with executive functions (β = 0.204-0.256, 95% CI = 0.031-0.436).

CONCLUSION

Although V̇O2peak is considered the gold standard indicator of CRF in children, peak performance (laps or running speed) and estimated V̇O2peak/Léger et al. derived from 20mSRT had stronger and more consistent associations with brain health outcomes than other indices of CRF in children with overweight/obesity.

Effect of physical activity levels on blood lipids, insulin resistance, and adipokines in children with obesity

PURPOSE

Our study was performed to observe children with obesity by using accelerometers and identify their differences in blood lipid levels, insulin resistance, and adipokines based on their physical activity levels.

METHODS

197 obese children were classified into three groups based on their physical activity levels over a period of 7 days, using the average counts per minute: Sedentary Time (ST), Light Physical Activity (LPA), and Moderate to Vigorous Intensity Physical Activity (MVPA). Blood lipids, including triglycerides (TG), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C), were analyzed. Insulin resistance was assessed using the Homeostatic Model Assessment of Insulin Resistance (HOMA-IR) formula. Adipokines, including leptin and resistin, were measured. Our results were obtained through one-way analysis of variance was employed, with Scheffe post-hoc analysis. The statistical significance level was set at p < 0.05 for all analyses.

RESULTS

Results showed that the levels of blood lipids (TG: p<0.001, TC: p<0.01, LDL-C: p<0.001, HDL-C: p< 0.05) and adipokines (Leptin, Resistin: p<0.01) of children who had obesity and maintained moderate to vigorous physical activity were healthier than those who engaged in ST or LPA. Specifically, children with obesity engaging in MVPA demonstrated blood lipid and adipokine levels that were normal or close to normal. However, no significant differences in insulin resistance were observed in all groups.

CONCLUSION

In summary, encouraging moderate to vigorous physical activity in children with obesity could help improve obesity indicators, such as blood lipids and adipokines.

Association between cardiorespiratory fitness level and insulin resistance in adolescents with various obesity categories

BACKGROUND

An association between cardiorespiratory fitness (CRF) and insulin resistance in obese adolescents, especially in those with various obesity categories, has not been systematically studied. There is a lack of knowledge about the effects of CRF on insulin resistance in severely obese adolescents, despite their continuous rise.

AIM

To investigate the association between CRF and insulin resistance in obese adolescents, with special emphasis on severely obese adolescents.

METHODS

We performed a prospective, cross-sectional study that included 200 pubertal adolescents, 10 years to 18 years of age, who were referred to a tertiary care center due to obesity. According to body mass index (BMI), adolescents were classified as mildly obese (BMI 100% to 120% of the 95^th percentile for age and sex) or severely obese (BMI ≥ 120% of the 95^th percentile for age and sex or ≥ 35 kg/m², whichever was lower). Participant body composition was assessed by bioelectrical impedance analysis. A homeostatic model assessment of insulin resistance (HOMA-IR) was calculated. Maximal oxygen uptake (VO₂max) was determined from submaximal treadmill exercise test. CRF was expressed as VO₂max scaled by total body weight (TBW) (mL/min/kg TBW) or by fat free mass (FFM) (mL/min/kg FFM), and then categorized as poor, intermediate, or good, according to VO₂max terciles. Data were analyzed by statistical software package SPSS (IBM SPSS Statistics for Windows, Version 24.0). P < 0.05 was considered statistically significant.

RESULTS

A weak negative correlation between CRF and HOMA-IR was found [Spearman’s rank correlation coefficient (r_s) = -0.28, P < 0.01 for CRF_TBW; (r_s) = -0.21, P < 0.01 for CRF_FFM]. One-way analysis of variance (ANOVA) revealed a significant main effect of CRF on HOMA-IR [F₍₂₂₀₀₎ = 6.840, P = 0.001 for CRF_TBW; F₍₂₂₀₀₎ = 3.883, P = 0.022 for CRF_FFM]. Subsequent analyses showed that obese adolescents with poor CRF had higher HOMA-IR than obese adolescents with good CRF (P = 0.001 for CRF_TBW; P = 0.018 for CRF_FFM). Two-way ANOVA with Bonferroni correction confirmed significant effect of interaction of CRF level and obesity category on HOMA-IR [F₍₂₂₀₀₎ = 3.292, P = 0.039 for CRF_TBW]. Severely obese adolescents had higher HOMA-IR than those who were mildly obese, with either good or poor CRF. However, HOMA-IR did not differ between severely obese adolescents with good and mildly obese adolescents with poor CRF.

CONCLUSION

CRF is an important determinant of insulin resistance in obese adolescents, regardless of obesity category. Therefore, CRF assessment should be a part of diagnostic procedure, and its improvement should be a therapeutic goal.

Physical Activity and the Development of Islet Autoimmunity and Type 1 Diabetes in 5- to 15-Year-Old Children Followed in the TEDDY Study

OBJECTIVE

This study investigated physical activity and its association with the development of islet autoimmunity and type 1 diabetes in genetically at-risk children aged 5-15 years.

RESEARCH DESIGN AND METHODS

As part of the longitudinal Environmental Determinants of Diabetes in the Young (TEDDY) study, annual assessment of activity using accelerometry was conducted from age 5 years. Time-to-event analyses using Cox proportional hazard models were used to assess the association between time spent in moderate to vigorous physical activity per day and the appearance of one or several autoantibodies and progression to type 1 diabetes in three risk groups: 1) 3,869 islet autoantibody (IA)-negative children, of whom 157 became single IA positive; 2) 302 single IA-positive children, of whom 73 became multiple IA positive; and 3) 294 multiple IA-positive children, of whom 148 developed type 1 diabetes.

RESULTS

No significant association was found in risk group 1 or risk group 2. A significant association was seen in risk group 3 (hazard ratio 0.920 [95% CI 0.856, 0.988] per 10-min increase; P = 0.021), particularly when glutamate decarboxylase autoantibody was the first autoantibody (hazard ratio 0.883 [95% CI 0.783, 0.996] per 10-min increase; P = 0.043).

CONCLUSIONS

More daily minutes spent in moderate to vigorous physical activity was associated with a reduced risk of progression to type 1 diabetes in children aged 5-15 years who had developed multiple IAs.

Is cardiorespiratory fitness a moderator of the relationship between sugar-sweetened beverage consumption and insulin resistance in schoolchildren?

PURPOSE

The aim of this study was to determine whether cardiorespiratory fitness (CRF) decreases the association between insulin resistance and sugar-sweetened beverage (SSB) consumption in a population-based sample of Spanish schoolchildren.

METHODS

This is a cross-sectional study including 430 schoolchildren (51.4% girls), aged 8-12 years, from 10 schools in Cuenca (Spain). Blood samples were drawn to measure fasting insulin levels. Homeostatic Model Assessment for Insulin Resistance (HOMA-IR) was also assessed. Data on SSB consumption were gathered using the Children's Eating Habits Questionnaire, which was completed by parents. The CRF level was determined by the 20 m Shuttle Run test and a curvilinear allometric model.

RESULTS

Our conditional regression estimates showed that CRF moderated the association of SSB consumption on insulin levels or HOMA-IR. In children who had levels of CRF < 34.4 ml/kg/min ml/kg/min (for insulin levels) or < 33.6 ml/kg/min (for HOMA-IR), the association between SSB consumption and fasting insulin levels or HOMA-IR raised. Among children with CRF levels between 34.4 and 52.1 ml/kg/min (for insulin levels) or 33.6-55.4 ml/kg/min (for HOMA-IR), the association of SSB consumption on insulin level or HOMA-IR neither increased nor decreased. Among children with CRF levels > 52.1 ml/kg/min (for insulin levels) or > 55.4 ml/kg/min (for HOMA-IR), the association of SSB consumption on fasting insulin levels or HOMA-IR decreased.

CONCLUSIONS

Our results showed that certain levels of CRF moderate the association between SSB consumption and insulin resistance in a population-based sample of Spanish schoolchildren.

The association of physical activity to oral glucose tolerance test outcomes in multiple autoantibody positive children: The TEDDY Study

OBJECTIVE

To examine the association of physical activity (PA), measured by accelerometry, to hemoglobin AIC (HbA1c) and oral glucose tolerance test (OGTT) outcomes in children who were multiple persistent confirmed autoantibody positive for type 1 diabetes (T1D).

METHODS

The Environmental Determinants of Diabetes in the Young (TEDDY) multinational study followed children from birth. Children ≥3 years of age who were multiple persistent confirmed autoantibody positive were monitored by OGTTs every 6 months. TEDDY children's PA was measured by accelerometry beginning at 5 years of age. We examined the relationship between moderate plus vigorous (mod + vig) PA, HbA1c, and OGTT in 209 multiple autoantibody children who had both OGTT and PA measurements.

RESULTS

Mod + vig PA was associated with both glucose and C-peptide measures (fasting, 120-min, and AUC); higher mod + vig PA was associated with a better OGTT response primarily in children with longer duration of multiple autoantibody positivity. Mod + vig PA also interacted with child age; lower mod + vig PA was associated with a greater increase in C-peptide response across age. Mod + vig PA was not related to fasting insulin, HOMA-IR or HbA1c.

CONCLUSIONS

The OGTT is the gold standard for diabetes diagnosis and is used to monitor those at high risk for T1D. We found higher levels of mod + vig PA were associated with better OGTT outcomes in children ≥5 years of age who have been multiple autoantibody positive for longer periods of time. Physical activity should be the focus of future efforts to better understand the determinants of disease progression in high-risk children.

Associations of physical activity, sedentary time, and diet quality with biomarkers of inflammation in children

We investigated the associations of physical activity (PA), sedentary time (ST), and diet quality with biomarkers of inflammation in 390 children (192 girls, 198 boys) aged 6-8 years. PA energy expenditure (PAEE), light PA, moderate PA (MPA), vigorous PA (VPA), moderate-to-vigorous PA (MVPA), and ST were assessed by combined movement and heart rate sensor. Finnish Children Healthy Eating Index was calculated using data from 4 d food records. Body fat percentage (BF%) was measured by dual-energy X-ray absorptiometry. High-sensitivity C-reactive protein (Hs-CRP), leptin, interleukin-6 (IL-6), adiponectin, tumour necrosis factor-α, and glycoprotein acetyls were measured from fasting blood samples. PAEE, MPA, VPA, and MVPA were inversely associated with hs-CRP (β=-191 to -139, 95% CI=-0.294 to -0.024), leptin (β=-0.409 to -0.301, 95% CI=-0.499 to -0.107), IL-6 (β=-0.136 to -0.104, 95% CI=-0.240 to -0.001) and PAEE, MPA, and MVPA were inversely associated with glycoprotein acetyls (β=-0.117 to -0.103, 95% CI=-0.213 to -0.001). ST was directly associated with hs-CRP (β=0.170, 95% CI=0.070-0.269), leptin (β=0.355, 95% CI=0.265-0.445), and IL-6 (β=0.105, 95% CI=0.005-0.205). VPA was inversely associated with hs-CRP, leptin, and IL-6 in children with higher BF% (β=-0.344 to -0.181, 95% CI=-0.477 to -0.033) but not among children with lower BF% (β=-0.007-0.033, 95% CI=-0.183-0.184). In conclusion, PA was inversely and ST directly associated with circulating levels of biomarkers of inflammation among children. Furthermore, we observed that PA was inversely associated with these biomarkers for inflammation in children with a higher BF%. HighlightsSystemic inflammation, as indicated by increased circulating concentrations of biomarkers for inflammation, may be important in causal pathways leading to insulin resistance, sub-clinical atherosclerosis, and eventually clinical manifestations of cardiovascular diseases.Higher levels of physical activity and lower levels of sedentary time were associated with more favourable inflammatory profile.Body fat percentage modified these associations and especially vigorous intensity physical activity was inversely associated with biomarkers of inflammation on children with higher body fat percentage but not in children with lower body fat percentage.

Parental insulin resistance is associated with unhealthy lifestyle behaviours independently of body mass index in children: The Feel4Diabetes study

Parental health is associated with children's health and lifestyles. Thus, the aim of the present study was to assess lifestyle behaviours of children of parents with insulin resistance (IR) and at risk of type 2 diabetes. 2117 European families from the Feel4Diabetes-study were identified as being at risk for diabetes with the FINDRISC questionnaire and included in the present study. One parent and one child per family were included. Parental IR was considered when homeostasis model assessment (HOMA) was equal or higher than 2.5. Children's screen-time, physical activity and diet were assessed and clustered by K-means. Weight and height were measured and children's body mass index (BMI) was calculated. For children, a Healthy Diet Score (HDS) was calculated. Linear regression and multilevel logistic regression analyses were performed to assess the associations between parental IR and children's lifestyle behaviours in 2021. Children of parents with IR had higher BMI (p < 0.001) and spent more screen time (p = 0.014) than those of non-IR parents. Children of parents with IR had a lower value in the breakfast and vegetable components of the HDS (p = 0.008 and p = 0.05). Four lifestyle clusters were found. Children of IR parents had higher odds of being in a non-healthy cluster (OR: 1.19; 95%CI: 1.001-1.437).

CONCLUSION

Having an IR parent was associated with a high screen time and an increased probability of having an unhealthy lifestyle pattern in children. These data point out that children's lifestyles should be assessed in families with IR parents to provide tailored interventions.

WHAT IS KNOWN

• Children with diabetic or insulin-resistant parents could also develop this condition. • Unhealthy lifestyles are directly related with insulin resistance even in children.

WHAT IS NEW

• Children from parents with insulin resistance have higher chances of unhealthy lifestyles. • A higher BMI was found for those children with an insulin-resistant parent.

Cross-sectional associations between cardiorespiratory fitness and NMR-derived metabolic biomarkers in children - the PANIC study

OBJECTIVE

Cardiorespiratory fitness has been inversely associated with cardiovascular risk across the lifespan. Some studies in adults suggest that higher cardiorespiratory fitness is associated with cardioprotective metabolite profile, but the evidence in children is lacking. Therefore, we investigated the cross-sectional association of cardiorespiratory fitness with serum nuclear magnetic resonance derived metabolic biomarkers in children.

METHODS

A population sample of 450 children aged 6-8 years was examined. Cardiorespiratory fitness was assessed by a maximal exercise test on a cycle ergometer and quantified as maximal power output normalised for lean body mass assessed by dual-energy X-ray absorbtiometry. Serum metabolites were assessed using a high throughput nuclear magnetic resonance platform. The data were analysed using linear regression analyses adjusted for age and sex and subsequently for body fat percentage (BF%) assessed by DXA.

RESULTS

Cardiorespiratory fitness was directly associated with high density lipoprotein (HDL) cholesterol (β=0.138, 95% CI=0.042 to 0.135, p=0.005), average HDL particle diameter (β=0.102, 95% CI=0.004 to 0.199, p=0.041), and the concentrations of extra-large HDL particles (β=0.103, 95% CI=0.006 to 0.201, p=0.038), large HDL particles (β=0.122, 95% CI=0.025 to 0.220, p=0.014), and medium HDL particles (β=0.143, 95% CI=0.047 to 0.239, p=0.004) after adjustment for age and sex. Higher cardiorespiratory fitness was also associated with higher concentrations of ApoA1 (β=0.145, 95% CI=0.047 to 0.242, p=0.003), glutamine (β=0.161, 95% CI=0.064 to 0.257, p=0.001), and phenylalanine (β=0.187, 95% CI=0.091 to 0.283, p<0.001). However, only the direct associations of cardiorespiratory fitness with the concentrations of HDL cholesterol (β=0.114, 95% CI=0.018 to 0.210, p=0.021), medium HDL particles (β=0.126, 95% CI=0.030 to 0.223, p=0.010), ApoA1 (β=0.126, 95% CI=0.030 to 0.223, p=0.011), glutamine (β=0.147, 95% CI=0.050 to 0.224, p=0.003), and phenylalanine (β=0.217, 95% CI=0.122 to 0.311, p<0.001) remained statistically significant after further adjustment for BF%.

CONCLUSIONS

Higher cardiorespiratory fitness was associated with a cardioprotective biomarker profile in children. Most associations were independent of BF% suggesting that the differences in serum metabolites between children are driven by cardiorespiratory fitness and not adiposity.

Predictors of postprandial glycaemia, insulinaemia and insulin resistance in adolescents

Postprandial glycaemia and insulinaemia are important risk factors for type 2 diabetes. The prevalence of insulin resistance in adolescents is increasing, but it is unknown how adolescent participant characteristics such as BMI, waist circumference, fitness and maturity offset may explain responses to a standard meal. The aim of the present study was to examine how such participant characteristics affect the postprandial glycaemic and insulinaemic responses to an ecologically valid mixed meal. Data from the control trials of three separate randomised, crossover experiments were pooled, resulting in a total of 108 participants (fifty-two boys, fifty-six girls; aged 12·5 (SD 0·6) years; BMI 19·05 (SD 2·66) kg/m2). A fasting blood sample was taken for the calculation of fasting insulin resistance, using the homoeostatic model assessment of insulin resistance (HOMA-IR). Further capillary blood samples were taken before and 30, 60 and 120 min after a standardised lunch, providing 1·5 g/kg body mass of carbohydrate, for the quantification of blood glucose and plasma insulin total AUC (tAUC). Hierarchical multiple linear regression demonstrated significant predictors for plasma insulin tAUC were waist circumference, physical fitness and HOMA-IR (F(3,98) = 36·78, P < 0·001, adjusted R2 = 0·515). The variance in blood glucose tAUC was not significantly explained by the predictors used (F(7,94) = 1·44, P = 0·198). Significant predictors for HOMA-IR were BMI and maturity offset (F(2,102) = 14·06, P < 0·001, adjusted R2 = 0·021). In summary, the key findings of the study are that waist circumference, followed by physical fitness, best explained the insulinaemic response to an ecologically valid standardised meal in adolescents. This has important behavioural consequences because these variables can be modified.

Effect of acute football activity and physical fitness on glycaemic and insulinaemic responses in adolescents

The present study examined the metabolic responses to an acute bout of football and the overall and moderating role of physical fitness on these responses, in adolescents. Thirty-six adolescents (16 girls, 20 boys; 12.6±0.5 y) completed two trials (60-min football and 60-min seated rest) separated by 7-d. Capillary blood samples were taken at baseline (60-min prior to exercise/rest), immediately, 30- and 60-min post-exercise and 30-, 60- and 120-min following a standardised lunch (1.5-, 2- and 3-h post-exercise), for the determination of blood glucose and plasma insulin concentrations. The median split of distance covered on the multi-stage fitness test was used to define high- and low-fit groups. Overall plasma insulin tAUC following lunch was lower in high-fit participants compared to low-fit (high-fit: 3784.2±1653.1 pmol·L^-1x120min, low-fit: 6457.3±3290.7 pmol·L^-1x120min; p<0.001), although there was no acute effect of the football session (p>0.05). Football reduced blood glucose concentration 1-h post-exercise compared to control (exercise: 3.8±0.6 mmol·L^-1, rest: 4.6±0.8 mmol·L^-1; p<0.001), but this was similar for the high- and low-fit participants (p>0.05). Blood glucose tAUC was not affected by exercise or physical fitness (p>0.05). These data emphasise the importance of physical fitness for metabolic health in adolescents, as well as the utility of football as a popular form of games-based activity for improving glucose regulation.

Effect of Sex, Body Mass Index and Physical Activity Level on Peak Oxygen Uptake Among 14-19 Years Old Adolescents

The aim was to describe longitudinal trends in peak oxygen uptake (VO_2peak) among 14- to 19-year-old adolescents in Norway, and to examine effects of sex, body mass index (BMI), and physical activity (PA) level on VO_2peak during adolescence. Of 124 invited students from two lower secondary schools in Norway, 116 eighth-grade students (61 boys and 55 girls; 14 years old at baseline) volunteered to participate. The study has a longitudinal design with 6 yearly repeated measures of body height and mass, VO_2peak and PA level. VO_2peak allometrically scaled to body mass raised to the power of 0.67 was measured using a walking or running incremental test on a treadmill, whereas PA level was self-reported. Among 696 possible observations, 555 (79.7%) were valid. Multiple linear regression and linear mixed model analyses were used to examine the associations between age, sex, BMI, PA level and VO_2peak. VO_2peak showed a non-linear pattern from age 14 to 19, with a distinct increase for boys peaking at age 17, while the results provide a flatter and more stable curve for girls. Sex, BMI and PA level together explained 43–71% of the variance in VO_2peak at the different age levels. Sex and PA level contributed independently to explain a significant proportion of the variance in VO_2peak at all measurement occasions, while BMI did not. Adjusted sex differences in VO_2peak increased over time, from 26.5 ml·kg^−0.67·min⁻¹ at age 14 to 55.5 ml·kg^−0.67·min⁻¹ at age 19. The independent contribution from PA level to the variance in VO_2peak increased from age 14 to 16 and then decreased. While PA level explained 32.5% of the total variance in VO_2peak for 16-year-olds, this number was 14% in 19-year-olds. In conclusion, aerobic power showed a non-linear pattern during adolescence, peaking at age 17. Sex and PA level explained a large proportion of the variance in VO_2peak, each of them being an independent contributor to VO_2peak. Aerobic power is linked to improved health and seems to depend largely on sex and PA level in adolescents, emphasizing the importance of maintaining a sufficient PA level during adolescence.

Cardiorespiratory fitness is strongly linked to metabolic syndrome among physical fitness components: a retrospective cross-sectional study

BACKGROUND

Maintaining a good level of physical fitness from engaging in regular exercise is important for the treatment and prevention of metabolic syndrome (MetS). However, which components constitutive of physical fitness confer the greatest influence remains controversial. This retrospective cross-sectional study aimed to investigate the association between MetS and physical fitness components including cardiorespiratory fitness, muscle strength, flexibility, and agility and to identify which physical fitness components have the largest influence on MetS.

METHODS

A total of 168 Japanese adult males aged 25-64 years were allocated into non-MetS, pre-MetS, and MetS groups according to the criteria recommended by the Japanese Society of Internal Medicine. Anthropometric measurement of body composition by whole-body dual-energy X-ray absorptiometry and measures related to MetS, including waist circumference, triglyceride level, high-density lipoprotein cholesterol level, blood pressure, glucose level, and physical fitness components, were assessed. For evaluation of cardiorespiratory fitness, muscle strength, flexibility, agility, and balance, maximal oxygen consumption (VO_2peak) and oxygen uptake at anaerobic threshold (VO_2AnT), handgrip strength and vertical jumping, trunk extension and flexion, stepping side to side, and single-leg balance task with the eyes closed were assessed, respectively.

RESULTS

A progressive tendency of increasing body weight, body mass index, whole-body lean and fat mass, percentage of whole-body fat mass, trunk lean and fat mass, percentage of trunk fat mass, arm fat mass, waist circumference, triglyceride level, systolic and diastolic blood pressure, and blood glucose level from the non-MetS group to the MetS group was significant (P < 0.05). Conversely, the cardiorespiratory endurance parameters VO_2peak and VO_2AnT and the high-density lipoprotein cholesterol level showed a progressively decreasing tendency across the groups (P < 0.01). In addition, a VO_2peak below 29.84 ml·kg·min^-1 (P = 0.028) and VO2_AnT below 15.89 ml·kg·min^-1 (P = 0.011) were significant risk components for pre-MetS and MetS. However, there was no significant tendency with respect to muscle strength, agility, and flexibility.

CONCLUSION

Cardiorespiratory fitness is strongly linked to metabolic syndrome among physical fitness components.