Effect of exercise training on nitric oxide and nitrate/nitrite (NOx) production: A systematic review and meta-analysis.

Background: Exercise and physical activity can improve circulation through various mechanisms, such as the increment of nitric oxide (NO) production, by affecting vascular endothelial nitric oxide synthase, and reducing reactive oxygen species (ROS). Although, theoretically, this mechanism is well known, studies in living subjects have made controversial findings regarding the association of NO production and its metabolites [nitrate/nitrite (NOx)] with physical activity. Hence, this systematic review and meta-analysis was designed to gather all these studies and evaluate the effects of exercise training, and physical activity duration and length on the mean change of serum/plasma NO and NOx. Method: We searched all available bibliographic electronic databases from inception through to May 2022 to include all randomized controlled trials (RCT) and quasi-experimental trials which assessed the effect of exercise and training on NO and NOx levels. Random-effects meta-analysis was used to pool the standardized mean difference (SMD) and 95% confidence interval (CI) of included RCT studies which assessed the effect of training. Stratified meta-analysis was performed according to the type of exercise (high-intensity interval training (HIIT), aerobic training (AT), the duration of exercise (≤8 and > 8 weeks), and length of exercise in each session ≥40 and 40 < minutes). Results: Overall, 15 and 10 studies were included in the systematic review and meta-analysis, respectively. According to the random-effects meta-analysis, exercise significantly increased the mean change of NO and NOx compared to control (SMD: 1.82, 95%CI: 1.14 to 2.49. In the stratified meta-analysis, the mean change of NO and NOx in the intervention group was significantly higher than in the control group in the AT (SMD: 1.36, 95%CI: 0.55-2.18), HIIT (SMD: 2.55, 95%CI: 1.14-3.96), duration of ≤8 (SMD: 2.29, 95%CI: 1.24-3.35) and > 8 weeks (SMD: 1.19, 95%CI: 0.52-1.86), length of ≥40 (SMD: 1.61, 95%CI: 1.04-2.18), and 40 < minutes in each session (SMD: 2.07, 95%CI: 0.79-3.35). Conclusion: The findings of this study indicate that, regardless of exercise duration, length, and type (AT or HIIT), exercise can significantly increase serum NO and NOx levels.

Effects of interval training on cardio metabolic risk factors and nitric oxide in type 2 diabetes patients: a randomized controlled trial.

PURPOSE: The purpose of this study was to investigate the effects of interval training on cardio metabolic risk factors and nitric oxide in type 2 diabetes patients. METHOD: This single blinded randomized controlled trial was conducted at cardiology clinic of Rajaee hospital in Karaj. Thirty female patients with type 2 diabetes randomly assigned to interval training exercise (n = 15) and control (n = 15). In interval training exercise patients received interval training exercise with 18 sessions (three sessions per week). Each training session took 25 min and consists a single set of exercise with 10 time repetitions. Training was performed on a cycle ergometer set in constant watt mode at a pedal cadence of 80-100 revolutions/min. Each repetition of the training takes 60 s and there will be a 60 s recovery pried between each repetition. Each training session include a 3-min warm-up and 2-min cool-down at 50 W for a total of 25 min. Blood samples and of all the subjects were taken at baseline, 3 weeks after intervention and at the end of the study (6 weeks). RESULTS: In intervention group, comparing with controls participants, a significant decrease were observed in levels of total cholesterol, triglyceride and HA1c after training program (p < 0.05). Moreover,exercise significantly increased the level of NOx (p < 0.05). Other cardiometabolic risk factors including SBP, DBP, FPG, LDL, HDL, insulin level, insulin resistance, HR, VO2 max, did not show significant differences between the two groups (p > 0.05). CONCLUSION: Results of current study showed that interval training as a type of planned physical activity can be effective in lowering cardiovascular risk factors, especially lowering cholesterol and triglycerides, and can also have a beneficial effect on improving NO.

Association of screen time and physical activity with health-related quality of life in Iranian children and adolescents.

BACKGROUND: Health-related quality of life (HRQoL) is a multidimensional concept with significant effects and children and adolescence; while physical activity (PA) and screen time (ST) have been suggested as its probable predictors. Present study aims to investigate the association of PA, ST and their combination, with HRQoL in a nationally-representative sample of Iranian children and adolescents. METHODS: As for the estimated sample size, 25,000 students aged 6-18 years were selected via multi-stage cluster sampling from 30 provinces of Iran. Sociodemographic data was obtained by using the questionnaire of the World Health Organization-Global school based student health survey (GSHS). Persian Pediatric Quality of Life inventory (PedsQL) and Physical Activity Questionnaire for the pediatric age group (PAQ-A) were applied for evaluating HRQoL and PA, respectively. PA scores 1-1.9 and 2-5 were respectively considered as low and high PA. The average duration of time spent on watching TV and leisure time computer use were considered as ST behaviors. ST of less than 2 h was considered low. RESULTS: Out of 25,000 invited individuals, 23,043 students (mean age: 12.5) completed the study (response rate: 92.17%). In linear regression models, ST duration had significant inverse association with total QoL (ß: - 0.49, p < 0.05). PA showed positive significant associations with HRQoL total score (ß: 1.8, p < 0.05). Joint association of PA and ST revealed the strongest association of "high PA-low ST" category with total HRQoL (ß: 2.2, p < 0.05); while "high PA-high ST" showed better total HRQoL score (ß: 1.3) compared to "low PA-low ST" subgroup. CONCLUSION: Both PA and ST are significantly and independently associated with HRQoL in Iranian children and adolescents; while the adverse effect of prolonged ST could be diminished by a high PA.

Association of adolescents' weight status with life satisfaction: role of self, peers, family and school perception; the CASPIAN-IV Study.

BACKGROUND: Although many public health programs have focused on prevention and control of obesity, their efficacy mostly depends on personal factors including perception of weight and personal understanding of the concept of being overweight. This study aims to investigate the association of adolescent's weight status with life satisfaction and explore the role of self, peers, family and school perception in this association. METHODS: Data were obtained from the fourth school-based survey entitled "Childhood and Adolescence Surveillance and Prevention of Adult Non-communicable Disease" (CASPIAN) Study. This survey was conducted among 14,880 urban and rural students aged 6-18 years. Two sets of valid and reliable questionnaire obtained from Global School Health Survey (GSHS) were completed by students and their parents. The students' questionnaire had several questions including life satisfaction and the perception of weight, peers, family and school. RESULTS: The study had a participation rate of 90.6% including 50.8% boys and 76% urban residents. Significant differences existed in Body Mass Index (BMI) and in perception of weight among girls and boys. Moreover, the prevalence of depression and being bullied were higher among girls and boys, respectively. Significant association was documented between life satisfaction and all variables including perception of weight, peers, family and school; the only exception was for BMI (P<0.05). In addition, students with normal weight had significantly higher life satisfaction in comparison with their obese counterparts (P<0.05). CONCLUSIONS: The present study documented significant association between life satisfaction and perception of self, peer, family and school with the exception of BMI in both genders.

Association of healthy foods intake with anthropometric measures and blood pressure in a national sample of Iranian children and adolescents: the CASPIAN-IV Study.

BACKGROUND: This study aims to evaluate the association of consuming healthy foods with anthropometric measures and blood pressure (BP) in a national sample of Iranian children and adolescents. METHODS: This nationwide study was conducted in 2011-2012 among 13,486 students, aged 6-18 years, selected by multistage cluster sampling from 30 provinces. Weight, height, waist circumference (WC), hip circumference (HC), wais to height ratio (WHtR), waist to hip ratio (WHR), as well as systolic and diastolic blood pressures (SBP, DBP) were measured. Healthy foods were considered as four categories including fresh fruits, dried fruits, vegetables, and dairy products. The frequency consumption of each of these foods was recorded as daily, weekly, and seldom. RESULTS: The intake of fruits was significantly associated with anthropometric indices. Moreover, a significant association was found between vegetables consumption, DBP levels, and anthropometric indices (except for WHtR and WHR). Milk consumption was significantly associated with anthropometric indices (except for WHtR and WHR). The odds of general obesity among participants who seldom consumed dried fruits was less than those who consumed daily (OR: 0.84, 95%CI: 0.74-0.96). We did not find any significant association for the frequency of fresh fruits and vegetables consumption with obesity, abdominal obesity, DBP and SBP. CONCLUSIONS: Consumption of dried fruits was associated with general obesity in children and adolescents. These results highlight the effect of dietary quality and food choices on weight control in children and adolescents.

Wrist circumference as a novel predictor of obesity in children and adolescents: the CASPIAN-IV study.

Background Recent studies have discussed the application of wrist circumference as an easy-to-use predictor of general and abdominal obesity. The aim of the current study is to evaluate the association of wrist circumference with generalized and abdominal obesity and to determine its sex- and age-specific optimal cutoff points in association with generalized and abdominal obesity in a national sample of pediatric population. Methods This nationwide survey was conducted among 14,880 students, aged 6-18 years, selected through a multistage, random cluster sampling method from rural and urban areas of 30 provinces in Iran from 2011 to 2012. Anthropometric indices (weight, height, wrist circumference, waist circumference [WC], hip circumference [HC]) were measured by standard protocols using calibrated instruments. Body mass index (BMI) and waist-to-height ratio (WHtR) were calculated. By considering the area under the curve (AUC) of the receiver operator characteristic (ROC) curves, we evaluated the association of wrist circumference with obesity indices and determined its sex- and age-specific optimal cutoff points in association with obesity. AUC: 0.5, AUC: 0.5-0.65 and AUC: 0.65-1.0 were interpreted as equal to chance, moderately and highly accurate tests, respectively. Results Overall, 13,486 children and adolescents with a mean age of 12.47±3.36 years completed the study (participation rate of 90.6%). In both genders, wrist circumference had a significant correlation with anthropometric measures including weight, height, BMI, WC, HC and WHtR. In all age groups and both genders, wrist circumference performed relatively well in classifying individuals into overweight (AUC: 0.67-0.75, p<0.001), generalized obesity (AUC: 0.81-0.85, p<0.001) and abdominal obesity (AUC: 0.82-0.87, p<0.001). Conclusions Wrist circumference is suggested to be a useful index for assessing excess weight in the pediatric age group. Its easy measurement without the need of calculation ratios might make it as a routine measurement in daily clinical practice and in large epidemiological studies.

Physical inactivity and associated factors in Iranian children and adolescents: the Weight Disorders Survey of the CASPIAN-IV study.

Introduction: This study aims to assess the associated factors of physical inactivity among Iranian children and adolescents at national level. The second objective is to assess the relationship of physical inactivity with anthropometric measures. Methods: Along with a national surveillance program, this survey on weight disorders was conducted among a nationally-representative sample of Iranian children and adolescents, aged 6-18 years. Students were selected by multi-stage cluster sampling from rural and urban areas of 30 provinces of Iran. The Physical Activity Questionnaire for Adolescents (PAQ-A) was used to assess physical activity (PA). Using PAQ-A instrument, PA of past week categorized as; low PA level, that included those who scored between 1 to 1.9 on the PAQ-A instrument and high PA level that included participants with estimated scores between 2-5 PAQ-A. Results: Participants were 23183 school students (50.8% boys) with a mean age of 12.55 ± 3.3 years, without significant difference in terms of gender. Totally, 23.48% of participants (13.84% of boys and 33.42% of girls) were physically inactive. In multivariate logistic regression model, with increased age in children and adolescence, the odds of a physically inactivity increased (OR: 1.08; 95% CI: 1.07-1.10). The odds of prevalence of both obesity and underweight were high in children and adolescents with low PA. There was a decreasing trend in PA in higher school grades. Conclusion: We found a considerably high prevalence of physical inactivity in Iranian children and adolescents, with higher rates among girls and older ages. However, we did not find correlation between PA and socioeconomic status (SES). Because of the positive relationship between PA and ST, future studies should consider the complex interaction of these two items. Multidisciplinary policies should be considered in increasing PA programs among children and adolescents.

Joint association of screen time and physical activity on self-rated health and life satisfaction in children and adolescents: the CASPIAN-IV study.

BACKGROUND: Self-rated health and life satisfaction are two subjective measures for assessing overall health status. This study aims to investigate the association of self-rated health and life satisfaction with physical activity and screen time. METHODS: As part of the fourth survey of a national surveillance program in Iran (CASPIAN-IV study), 14 880 students aged 6 to 18 years were selected via multi-stage cluster sampling from 30 provinces. Data were obtained from the WHO Global School-Based Student Health Survey questionnaire. RESULTS: A total of 13 486 students with mean age of 12.47 (SD 3.36) completed the study. In crude model both prolonged screen time and physical activity were associated with favorable life satisfaction and self-rated health. However, in multivariate analysis only high physical activity was associated with good self-rated health (OR 1.37) and life satisfaction (OR 1.39), while prolonged screen time was not associated with good self-rated health (OR 1.02) and life satisfaction (OR 0.94). For combined screen time-physical activity variable, low screen time-high physical activity combination had the highest OR for both good self-rated health (OR 1.37) and life satisfaction (OR 1.43) in multivariate analysis. CONCLUSIONS: Our findings suggest that increasing physical activity is more crucial than emphasizing reducing screen time in improving the well-being of children and adolescents.

Prevalence of physical inactivity in Iran: a systematic review.

Introduction: Physical inactivity is one of the most important risk factors for chronic diseases, including cardiovascular disease, cancer, and stroke. We aim to conduct a systematic review of the prevalence of physical inactivity in Iran. Methods: We searched international databases; ISI, PubMed/Medline, Scopus, and national databases Irandoc, Barakat knowledge network system, and Scientific Information Database (SID). We collected data for outcome measures of prevalence of physical inactivity by sex, age, province, and year. Quality assessment and data extraction has been conducted independently by two independent research experts. There were no limitations for time and language. Results: We analyzed data for prevalence of physical inactivity in Iranian population. According to our search strategy we found 254 records; of them 185 were from international databases and the remaining 69 were obtained from national databases after refining the data, 34 articles that met eligible criteria remained for data extraction. From them respectively; 9, 20, 2 and 3 studies were at national, provincial, regional and local levels. The estimates for inactivity ranged from approximately 30% to almost 70% and had considerable variation between sexes and studied sub-groups. Conclusion: In Iran, most of studies reported high prevalence of physical inactivity. Our findings reveal a heterogeneity of reported values, often from differences in study design, measurement tools and methods, different target groups and sub-population sampling. These data do not provide the possibility of aggregation of data for a comprehensive inference.

Association of neck circumference with general and abdominal obesity in children and adolescents: the weight disorders survey of the CASPIAN-IV study.

OBJECTIVES: This study aimed to evaluate the association of neck circumference (NC) with obesity to determine the sex-specific and age-specific optimal cut-off points of this measure in association with obesity in a national sample of the Iranian paediatric population. METHODS: This survey on weight disorders was conducted among a national sample of Iranian children and adolescents, aged 6-18 years. Using the area under the curve (AUC) of the receiver operator characteristic curves, we evaluated the association of NC with general and abdominal obesity. RESULTS: This national survey was conducted among 23 043 school students (50.8% boys) with a mean age (SD) of 12.55 (3.31) years. A significant association was documented between NC and other anthropometric measures in both sexes and in the whole population. In all age groups and genders, NC performed relatively well in classifying participants to overweight (AUC: 0.67 to 0.75, p<0.001), general obesity (AUC: 0.81 to 0.85, p<0.001) and abdominal obesity (AUC: 0.73 to 0.78, p<0.001). CONCLUSIONS: NC can be considered as a simple time-saving clinical tool for obesity detection in large population-based studies in children and adolescents. It is significantly correlated with indices of adiposity and can reliably identify children with general and abdominal obesity in the Iranian paediatric population.

Joint Association of Screen Time and Physical Activity with Cardiometabolic Risk Factors in a National Sample of Iranian Adolescents: The CASPIANIII Study.

Metabolic syndrome (MetS) and its contributing factors are considered important health problems in the pediatric age group. This study was designed to assess the joint association of ST and PA with cardiometabolic risk factors among Iranian adolescents. A representative sample of 5625 (50.2% boys) school students with a mean age of 14.73 (SD: 2.41) were selected through multistage random cluster sampling method from urban and rural areas of 27 provinces in Iran. ST and PA were assessed by self-administered validated questionnaires. Anthropometric measures (height, weight and waist circumference (WC)) and MetS components (abdominal obesity, elevated blood pressure (BP), low high-density lipoprotein cholesterol (HDL-C), elevated triglycerides (TG) and high fasting blood sugar (FBG)) were measured according to standardized protocols. MetS was defined according to the Adult Treatment Panel III criteria modified for the pediatric age group. Moreover, elevated total cholesterol (TC), elevated low-density lipoprotein cholesterol (LDL-C), and generalized obesity were considered as other cardiometabolic risk factors. Students with high ST levels had significantly higher body mass index z-score (BMI z-score), WC, TG, LDL-C, and BP as well as lower HDL-C level; whereas those with high PA levels had significantly higher HDL-C levels as well as lower BMI z-score, TC, and BP. Adolescents with low PA/ high ST levels had significantly higher BMI, WC, LDL-C levels, as well as higher SBP and DBP compared to their other counterparts. In Multivariate model, joint effect of low PA/ high ST (compared to the high PA/low ST group) increased the odds of overweight, abdominal obesity and low HDL-C and decreased the odds of elevated TC. The findings of this study showed that joint association of high ST and low PA have direct association with abdominal obesity, overweight and low HDL-C and indirect association with elevated TC.

Level of physical activity and screen time among Iranian children and adolescents at the national and provincial level: The CASPIAN-IV study.

Background: There are few epidemiological reports on adherence to physical activity (PA) and screen-time (ST) recommendations among Iranian children and adolescents at the provincial level. We used nationally representative data to provide recent prevalence estimates of Iranian children who met the recommendations for PA and ST. Methods: This nationwide study was conducted among 14,880 students aged 6-18 years from 30 provinces of Iran. The frequency of the recommended level for PA (>1 hours/week) and ST (<2 hours/day) and different combinations of PA and ST was determined in the studied population. Results: In this study, 13,486 students (response rate: 90.6%) were studied. Overall, 18.62%, 34.11%, 50.66% and 9.63% of the students reported high ST, low level of PA, high TV watching and high computer working, respectively. The frequency of the recommended level of PA and ST was 53.92%. Of the studied population, 6.63% had low PA and high ST. Paradox combinations of low PA and low ST and moderate/high PA and high ST was prevalent among 27.47% and 6.26% of the children and adolescents. The lowest and highest frequency of recommended level of PA and ST was 38.9% and 65%, respectively. The lowest and highest frequency of low PA and high ST was 1.87% and 13.77%, respectively. Conclusion: The results of this study revealed that the frequency of low PA was high and that approximately 46% of the students did not meet the recommended level of PA and ST. The findings indicated that preparing facilities for improving PA level among children should be the main priority in our future interventions in this field.

Is the association of continuous metabolic syndrome risk score with body mass index independent of physical activity? The CASPIAN-III study.

BACKGROUND/OBJECTIVES: Although the association of body mass index (BMI) with metabolic syndrome (MetS) is well documented, there is little knowledge on the independent and joint associations of BMI and physical activity with MetS risk based on a continuous scoring system. This study was designed to explore the effect of physical activity on interactions between excess body weight and continuous metabolic syndrome (cMetS) in a nationwide survey of Iranian children and adolescents. SUBJECTS/METHODS: Data on 5,625 school students between 10 and 18 years of age were analyzed. BMI percentiles, screen time activity (STA), leisure time physical activity (LTPA) levels, and components of cMetS risk score were extracted. Standardized residuals (z-scores) were calculated for MetS components. Linear regression models were used to study the interactions between different combinations of cMetS, LTPA, and BMI percentiles. RESULTS: Overall, 984 (17.5%) subjects were underweight, whereas 501 (8.9%) and 451 (8%) participants were overweight and obese, respectively. All standardized values for cMetS components, except fasting blood glucose level, were directly correlated with BMI percentiles in all models (P-trend < 0.001); these associations were independent of STA and LTPA levels. Linear associations were also observed among LTPA and standardized residuals for blood pressure, high-density lipoprotein, and waist circumference (P-trend < 0.01). CONCLUSIONS: Our findings suggest that BMI percentiles are associated with cMetS risk score independent of LTPA and STA levels.

Effects of sprint interval and continuous endurance training on serum levels of inflammatory biomarkers.

Chronic and inflammatory diseases are major causes of mortality. Although the anti-inflammatory effects of exercise have been confirmed, but the effect of different types of exercise on inflammatory markers is different. The aim of this study is comparing the effects of two types of sprint interval (SIT) and continuous endurance (CET) training on inflammatory markers. Sixteen students who had recreational activities participated in this study and were randomly assigned to one of the two protocols. The SIT protocol consisted of four to six 30-s "all-out" Wingate tests separated by 4 minutes of recovery and The CET protocol included 90-120 minutes of cycling at 65% Vo2max. The two protocols were performed 3 days per week and for two weeks. In each group, two blood samples were collected before and 2 days (24 and 48 hrs) after the training. Results showed that there was no significant difference between the two training protocols on all measured parameters (p>0.05). The results of present study showed that the SIT and CET have identical effects on inflammatory markers.