Ventilatory efficiency and rate of perceived exertion in obese and non-obese children performing standardized exercise

Ventilatory response and dyspnea on exertion in children with obesity and respiratory symptoms

We investigated whether the exercise ventilatory response is associated with dyspnea on exertion (DOE) in children with (CWO;n = 25) and without (CWOO;n = 49) obesity, and with obesity and respiratory symptoms (CWORS;n = 14). The ventilatory response to exercise (V̇E/V̇CO2 slope) and ratings of perceived breathlessness (RPB, Borg 0-10 scale) were measured during 6-min cycling at 45 % maximal work rate. The V̇E/V̇CO2 slope (CWOO=34 ± 7; CWO=34 ± 5; CWORS=37 ± 6) and RPB (CWORS=4.0 ± 3.4; CWOO=2.5 ± 1.7; CWO=3.2 ± 2.1) were similar among groups (p > 0.05). A significant association between the V̇E/V̇CO2 slope and RPB in CWORS (r2=0.49;p < 0.05) was observed. To investigate this relationship more closely, children with an RPB≤ 2 were classified as having no or mild DOE (-DOE;n = 39;RPB=1.2 ± 0.7), and those with RPB≥ 3 were classified as having moderate to severe DOE (+DOE;n = 49;RPB=4.7 ± 1.9). +DOE had a higher V̇E/V̇CO2 slope (+DOE=36 ± 6;-DOE=33 ± 5;p = 0.02), higher breathing frequency, and higher V̇E (%max;p < 0.05). These findings suggest a heightened sensitivity to ventilatory demand among children, and that +DOE may be driven by factors other than obesity alone, possibly increased ventilatory response to exercise.

Behavioral Counseling for Weight Management by Pediatric Nurse Practitioners: A Quantitative Cross-Sectional Study

INTRODUCTION

This study assessed counseling by pediatric nurse practitioners (PNPs) for management of overweight and obesity.

METHOD

Using a cross-sectional design, 1,058 PNPs completed a one-time survey regarding counseling for healthy body weight, physical activity, and consumption of protein, fruits and vegetables.

RESULTS

Study findings suggest PNPs are using behavioral counseling for weight management in pediatric patients. Counseling was more frequent for healthy body weight, fruit and vegetable intake, and physical activity than for protein consumption and muscle strengthening. Furthermore, when PNPs counseled for healthy body weight they were also more likely to counsel for physical activity (OR = 25.99 [95% CI: 19.25, 35.11]), fruit and vegetable intake (OR = 22.35 [95% CI: 16.71, 29.88]), protein intake (OR = 9.82 [95% CI: 7.60, 12.69]), and muscle strengthening (OR = 6.41 [95% CI: 4.98, 8.24]).

DISCUSSION

PNPs are counseling for healthy body weight and necessary behavioral tools, but increased emphasis on muscle strengthening may benefit overweight and obese youth.

Brazilian Guideline for Exercise Testing in Children and Adolescents - 2024

CLASSES OF RECOMMENDATION

LEVELS OF EVIDENCE

Physiological response during exercise is preserved in children exposed to a suboptimal gestational environment

OBJECTIVE

This study investigated whether exposure to suboptimal gestational factors (SGFs) alters mechanical efficiency (ME) and substrate oxidation during rest and exercise in children as a mechanism contributing to obesity.

METHODS

Data from the Quebec Adiposity and Lifestyle Investigation in Youth cohort were used. Children aged 8 to 10 years performed an incremental maximal cycling test with indirect calorimetry. Their ME was measured during submaximal and maximal effort. The substrate oxidation during rest and submaximal effort was also computed. ME and substrate oxidation results between children exposed to each SGF during pregnancy (gestational diabetes mellitus: n = 68; hypertensive disorders: n = 49; maternal smoking: n = 77) and nonexposed children (n = 370) were compared.

RESULTS

No difference was observed for ME during submaximal (F[3,540] = 0.46, p = 0.713) and maximal effort (F[3,545] = 0.86, p = 0.463) between exposed and nonexposed children. The percentage contributions of lipids and carbohydrates did not differ during rest (F[3,545] =1.68, p = 0.169) or submaximal exercise (F[3,544] = 0.31, p = 0.534) between exposed and nonexposed children.

CONCLUSIONS

Children exposed to investigated SGFs display a similar physiological response regarding ME and substrate oxidation during rest and exercise compared to nonexposed children. Future studies should confirm these novel results and continue investigating other research avenues to explain the higher risk of obesity in this population.

Aerobic exercise capacity is normal in obesity with or without metabolic syndrome

BACKGROUND

Obesity might be a cause of limited aerobic exercise capacity. It is often associated with metabolic syndrome (MS) that includes cardiovascular comorbidities as arterial hypertension. Cardiopulmonary exercise testing (CPET) is the gold-standard to assess aerobic capacity and discriminate causes of dyspnea.

AIM

To evaluate aerobic capacity in obesity and if MS or hypertensive treatment impacts on the CPET profile.

METHODS

CPET of 146 obese patients, whom 33 and 31 were matched for MS and antihypertensive medication, were analyzed. VO_2peak (mL/min/Kg) was reported in percentage of predicted value, or, divided by body weight, fat free mass (FFM) or body weight expected for a body mass index of 24 (BMI24).

RESULTS

VO_2peak (20,8 ± 4,4 mL/min/Kg) was normal when expressed in percentage predicted for obesity (111 ± 22%pred) or divided by FFM and weight_BMI24 (33,6 ± 5,6 and 30,6 ± 6,2 respectively). The latter correlated better with maximal work rate (r = 0,7168, p < 0,001). Obese patients showed normal ventilatory efficiency (ventilation to carbon dioxide production slope: 28 ± 4), VO₂ to work rate (10,2 ± 1,6 mLO₂/Watt) and, slightly elevated heart rate to VO₂ slope (4,0 ± 1,1 bpm/mL/min/Kg). Compared to normotensives, hypertensive medicated patients had higher blood pressure at anaerobic threshold (142 ± 23 vs 158 ± 26 mmHg, p = 0,001) but not at maximal exercise (189 ± 31 vs 201 ± 23 mmHg, p = NS), and, had lower actual maximal heart rate (155 ± 23 vs 143 ± 25 bpm, p = 0,03). There was no difference between obese patients with or without MS.

CONCLUSION

Obese people with or without MS present with similar and normal aerobic profile related to the excessive body weight. VO_2peak divided by weight_BMI24 is an easy and clinical meaningful index for obese patients.

The Omni Scale Is Not Suitable for Assessing Self-Perceived Exertion during Physical Activity in Preschoolers

INTRODUCTION

We aimed to identify the utility, reliability, and validity of an adapted version of the OMNI self-perceived exertion (PE) rating scale in preschoolers.

POPULATION AND METHODS

Firstly, 50 (mean age ± standard deviation [SD] = 5.3 ± 0.5 years, 40% girls) performed a cardiorespiratory fitness (CRF) test twice, with a one-week interval between assessments, and rated their PE either individually or in groups. Secondly, 69 children (mean age ± SD = 4.5 ± 0.5 years, 49% girls) performed two CRF tests, separated by a one-week interval, twice and rated their self-PE. Thirdly, the heart rate (HR) of 147 children (mean age ± SD = 5.0 ± 0.6 years, 47% girls) were compared against self-rated PE after finishing the CRF test.

RESULTS

Self-assessed PE differed when the scale was administered individually (e.g., 82% rated PE with 10) or in groups (42% rated PE with 10). The scale showed poor test-retest reliability (ICC:0.314-0.031). No significant associations were found between the HR and PE ratings.

CONCLUSIONS

An adapted version of the OMNI scale was found not suitable for assessing self-PE in preschoolers.

Systematic Review and Meta-Analysis of the Relationship between Actual Exercise Intensity and Rating of Perceived Exertion in the Overweight and Obese Population

The number of overweight (OW) and obese (OB) children, adolescents, and adults has increased globally. Exercise intensity, both actual and perceived, is a significant factor in a variety of health-related investigations and rehabilitation trainings. Despite this, literature on the connection between actual exercise intensity and the rating of perceived exertion (RPE) in overweight and obese populations is lacking. A systematic review, meta-analysis, combined analysis of variance (Brown-Forsythe ANOVA), and Spearman correlation were performed to fill this gap. After preliminary assessments, ten studies were classified as having a low risk of bias and a degree of heterogeneity (I² = 34%; p = 0.05). The RPE scores (F = 0.032; p = 0.859), physiological index (percentage of maximal heart rate (%HR_max) (F = 0.028; p = 0.869), and percentage of maximal oxygen uptake (%VO_2max) (F = 2.434; p = 0.136) demonstrated consistency without being significantly different between the normal weight (NW) and OW/OB groups. The RPE scores varied by age (NW (coefficient values) = 0.677 ***, OW = 0.585 **), as well as by indoor temperature (OW only, coefficient values = 0.422 *), body mass index (NW (coefficient values) = 0.516 **, OW = 0.580 **), and test time (NW only, coefficient values = 0.451 *). We conclude that RPE is appropriate for the following OW and OB people: (1) those who are older than 21.5 (the lowest age in the group of ≥18) years old and younger than 58.6 (the highest age in the group of ≥18) years old, without any other diseases, and (2) those who engage in low-intensity exercise while maintaining a standard indoor temperature. Future studies may address alternative techniques for increasing the reliability of longitudinal comparisons and gender comparisons, as well as investigate other possible confounding factors.

Dynamic physiological responses in obese and non-obese adults submitted to cardiopulmonary exercise test

PURPOSE

Obese individuals have reduced performance in cardiopulmonary exercise testing (CPET), mainly considering peak values of variables such as oxygen uptake ([Formula: see text]), carbon dioxide production ([Formula: see text]), tidal volume (Vt), minute ventilation ([Formula: see text]) and heart rate (HR). The CPET interpretation and prognostic value can be improved through submaximal ratios analysis of key variables like [Formula: see text], [Formula: see text], [Formula: see text] [Formula: see text] and oxygen uptake efficiency slope (OUES). The obesity influence on these responses has not yet been investigated. Our purpose was to evaluate the influence of adulthood obesity on maximal and submaximal physiological responses during CPET, emphasizing the analysis of submaximal dynamic variables.

METHODS

We analyzed 1,594 CPETs of adults (755 obese participants, Body Mass Index ≥ 30 kg/m2) and compared the obtained variables among non-obese (normal weight and overweight) and obese groups (obesity classes I, II and III) through multivariate covariance analyses.

RESULT

Obesity influenced the majority of evaluated maximal and submaximal responses with worsened CPET performance. Cardiovascular, metabolic and gas exchange variables were the most influenced by obesity. Other maximal and submaximal responses were altered only in morbidly obese. Only a few cardiovascular and ventilatory variables presented inconsistent results. Additionally, Vtmax, [Formula: see text], Vt/Inspiratory Capacity, Vt/Forced Vital Capacity, Lowest [Formula: see text], [Formula: see text], and the y-intercepts of [Formula: see text] did not significantly differ regardless of obesity.

CONCLUSION

Obesity expressively influences the majority of CPET variables. However, the prognostic values of the main ventilatory efficiency responses remain unchanged. These dynamic responses are not dependent on maximum effort and may be useful in detecting incipient ventilatory disorder. Our results present great practical applicability in identifying exercise limitation, regardless of overweight and obesity.

Cardiopulmonary Capacity in Overweight and Obese Children and Adolescents: A Cross-Sectional Study

Background: One of the objective methods of assessing the level of cardiopulmonary capacity in overweight and obese children and adolescents is cardiopulmonary exercise testing (CPET).

Aims: The purpose of present study is an evaluation of aerobic capacity in high body mass index (BMI) children and adolescents by comparing them with a normal weight control group by CPET.

Methods and Procedures: The subjects were recruited from participants of the Program of Treatment for Overweight and Obese Children organized by a local pediatric rehabilitation center in Poland. Based on BMI for age and gender, two validation groups were selected: (1) a group of overweight children (n = 49) and (2) a group of obese children (n = 48). The study included also 53 normal weight participants as a reference group (REF). The study consisted of two parts: anthropometric measurements and CPET. The Godfrey protocol for CPET was applied.

Outcomes and Results: In this study, obese children and adolescents showed similar absolute VO_2peak values in liters per minute (1.64 L/min) compared to overweight children (1.48 L/min), but significantly higher than children with normal body weight (1.39 L/min). The obese children and adolescents presented lower VO_2peak in relation to body weight (25.44 ml/kg/min) compared to their peers with normal body weight (36.5 ml/kg/min), and overweight children (29.18 ml/kg/min).

Conclusion and Implications: The main finding of our study was recognition of significant differences between cardiopulmonary capacity parameters in obese children in comparison not only to normal weight peers, but to overweight, too.

Influence of grade of obesity on the achievement of VO2max using an incremental treadmill test in youths

The purpose of this study was to analyze the influence of grade of obesity on the probability of achieving a VO2 plateau and threshold secondary criteria for verifying VO2max during a treadmill walk test in youths with obesity. Therefore, 72 youths with obesity (aged 8-16) performed an incremental treadmill walk test to exhaustion during which oxygen uptake (VO2), minute ventilation (VE), heart rate (HR) and rating of perceived exertion were continuously measured. HR corresponding to a "hard" level of perceived exertion was reported and expressed as a percentage of the predicted HRmax. The rate of achievement of criteria for validation VO2max (VO2 plateau; HR>95% theoretical HRmax; RER>1.0; rating of perceived exertion ≥ "hard") was compared between participants with grade I and grade II obesity. 37% of the participants achieved a VO2 plateau and 23% achieved both an HR>95% and RER >1.0. Youths with grade II obesity had lower minute ventilation (p<0.01) tended to be more likely to reach an HR>95% (OR = 0.33; P=0.06) and a "hard" rating of perceived exertion than grade I (OR = 4.5; P=0.07). However, there was no influence of grade of obesity on the achievement of VO2 plateau, and RER>1.0.

Does schoolbag carriage equally affect obese/overweight and healthy-weight children?

Discrepancies exist in backpack load recommendations for obese/overweight children, and the recommendations do not consider school trolleys. This study analysed obese/overweight and healthy-weight students' perceived load and fatigue when carrying schoolbags and their gait kinematics and rate of perceived exertion (RPE) when carrying backpacks or pulling school trolleys with different loads. Twelve obese/overweight and 36 healthy-weight students were asked about their perceived load and fatigue in carrying their schoolbags to school. Then, a kinematic gait analysis was completed in students walking unloaded or transporting 10%, 15% or 20% of their bodyweight (BW) in a backpack or trolley. RPE was recorded after each condition. The average hip rotation and knee adduction angles differed between body mass index (BMI) groups. The healthy-weight group reported higher RPEs than the overweight/obese group when pulling a trolley with 10-15% BW. In conclusion, both BMI groups responded similarly to load and schoolbag type.

Effect of Children's Weight Status on Physical Activity and Sedentary Behavior during Physical Education, Recess, and After School

Children's body mass index may affect physical activity (PA) participation. Therefore, this study examined the effect of children's weight status on underserved elementary school children's PA and sedentary behavior (SB) throughout the segmented day. Participants were 138 children (X¯age = 8.14 years). Children's height and weight were measured with subsequent classification of children as healthy weight or overweight/obese. Durations of moderate-to-vigorous PA (MVPA), light PA (LPA), and SB during physical education (PE), morning recess, lunch recess, after school, and overall were assessed via accelerometry over three days. Independent t-tests evaluated differences in children's MVPA, LPA, and SB during each daily segment by weight status. Significantly higher MVPA was observed for children of healthy weight status versus children with overweight/obesity during morning recess, t(136) = 2.15, p = 0.03, after school, t(136) = 2.68, p < 0.01, and overall, t(136) = 2.65, p < 0.01. Interestingly, comparisons of children of healthy weight status and children with overweight/obesity's LPA and SB during the after-school segment revealed a trend wherein children with overweight/obesity participated in slightly greater LPA/less SB than children of healthy weight status. Higher MVPA was observed among children of healthy weight versus children with overweight/obesity during most daily segments. Concerted efforts should focus on increasing MVPA among children with overweight/obesity.

Too much or too little? Exploring effort perception in schizophrenia within the framework of motivational intensity theory

Introduction: To explain motivational difficulties in schizophrenia (SZ), attention has focused on the reward system and effort-based decision-making deficits. However, according to motivational intensity theory (MIT), effort is not directly determined by reward but by task difficulty. Moreover, no studies have examined the effort perception in the SZ. Therefore, this cross-sectional study compared effort perception in SZ group with healthy controls. Method: Task difficulty was manipulated by increasing the distance covered (from 8 to 48 metres). Walking speed, perceptions of difficulty and effort were assessed for all difficulty levels. Clinical and bodyweight variables were recorded. Results: As postulated by MIT, perceived effort and difficulty increased with task difficulty in both groups. Perceived effort and difficulty were higher in the SZ group. Perceptions of effort were positively correlated with BMI in SZ, but not with clinical variables. Importantly, although SZ patients perceived the task as more effortful, walking speed was similar between groups. Conclusions: Taken together, these results suggested that individuals with SZ perceived more strongly the effort and the difficulty of the task but could mobilise more effort to complete it. This observation may explain in part the decrease in engaging in physical demanding activities in daily life in SZ.

Thermoregulatory and perceptual responses of lean and obese fit and unfit girls exercising in the heat

OBJECTIVE

To verify the thermoregulatory and perceptual responses of obese and lean girls, either fit or unfit, exercising in the heat at a similar rate of metabolic heat production per unit body mass.

METHODS

A total of 34 pubescent girls were allocated in four groups: 12 obese fit, 9 obese unfit, 5 lean fit, and 8 lean unfit. The obese groups (13.2±1.4 years, 40.5%±5.8% fat by DXA) differed in their aerobic fitness (V˙O_2peak 76.0±8.1 vs. 56.6±5.8mL.kgmusclemass^-1.min^-1), as well as the lean groups (13.1±1.6 years, 24.0%±4.8% fat) (V˙O_2peak 74.5±2.9 vs. 56.2±5.0mL.kgmuscle mass^-1min^-1). Girls cycled two bouts of 25min with a 10min rest in between, at ∼5.4W.kg^-1 in the heat (36°C and 40% relative humidity) and they were kept euhydrated. Rectal and skin temperatures and heart rate were measured every 5min. Perceptual responses were evaluated throughout the exercise.

RESULTS

Initial rectal temperature was higher in the obese subjects compared to the lean subjects (37.5±0.3 and 37.2±0.3°C). No difference was observed among the girls whom were obese (eight fit or unfit) and lean (also fit or unfit) throughout the exercise in rectal temperature (37.6±0.2, 37.5±0.3, 37.5±0.3, 37.4±0.3°C, respectively), skin temperature (34.8±0.8, 35.1±1.0, 34.4±0.9, 35.2±0.9°C), and heart rate (128±18; 118±12, 130±16, 119±16beatsmin^-1). No differences were observed in perceptual responses among groups.

CONCLUSION

Regardless of the adiposity or aerobic fitness, pubescent girls had similar thermoregulatory and perceptual responses while cycling in the heat at similar metabolic heat production.

External dead space explains sex-differences in the ventilatory response to submaximal exercise in children with and without obesity

We compared the exercise ventilatory response (slope of the ventilation, V̇_E and carbon dioxide production, V̇CO₂ relationship) in boys and girls with and without obesity. 46 children with obesity (BMI percentile: 97.7 ± 1.4) and 27 children without obesity (BMI percentile: 55.1 ± 22.2) were included and divided into groups by sex (with obesity: 17 girls and 29 boys; without obesity: 13 girls and 14 boys). A 6 min constant load cycling test at 45 % of peak work rate was performed. The V̇_E/V̇CO₂ slope was similar (p = 0.67) between children with (32.7 ± 4.3) and without (32.2 ± 6.1) obesity; however, it was higher (p = 0.02) in girls (35.4 ± 5.6) than boys (32.6 ± 4.9). We also examined a corrected V̇_E/V̇CO₂ slope for the effects of mechanical dead space (V_DM), by subtracting V̇_DM from V̇_E (V̇_Ecorr/V̇CO₂ slope). The V̇_Ecorr/V̇CO₂ slope remained similar (p = 0.37) between children with (26.8 ± 3.2) and without obesity (26.1 ± 3.1); however, no sex differences were observed (p = 0.13). Therefore, V_DM should be accounted for before evaluating the V̇_E/V̇CO₂ slope, particularly when making between-sex comparisons.

Respiratory responses and rating of perceived exertion of severely obese adolescents during continuous and intermittent graded walking protocols: Application to cardiorespiratory field tests

During 20 m shuttle tests, obese adolescents may have difficulty achieving maximum cardiorespiratory performance due to the presence of braking-relaunch phases (BRP). Nineteen obese adolescents aged 15.2 ± 1.5 years (body mass index [BMI] = 39.7 ± 5.9 kg.m^-2) performed three graded walking exercises on a 50 m track at speeds between 3 and 6 km/h: a continuous-straight-line protocol (C), a continuous protocol that required turning back every 30 sec (C-BRP) and an intermittent protocol that consisted of successively walking then resting for 15 sec (15-15). Oxygen uptake (VO₂), aerobic cost of walking (Cw), ventilation (VE) and rating of perceived exertion (RPE) were measured at each stage during the protocols. During C-BRP, the responses were not significantly higher compared with C (p > 0.30). During 15-15, the VO₂, Cw and VE were ~ 15 to 25% lower than during C beginning at 4 km/h (p < 0.05). In obese adolescents, the respiratory impact of sudden directional changes during the 20 m shuttle-type test appeared to be minor at walking speeds. During the 15-15 test, the intensity increases more progressively, and this design may encourage obese adolescents to walk further than during a continuous test.

Cardiovascular risk profile, oxygen uptake, and perceived exertion rate in children with obesity: the interactive effect of exercise intensity and duration

BACKGROUND

Although physical exercise is a crucial element in the management of childhood obesity, the most effective training intensity and duration remain controversial. The primary purpose of this study was to analyze the interaction effects of exercise intensity and duration on cardiovascular risk profile, maximum oxygen uptake (VO 2 max ), and rating of perceived exertion (RPE) in obese children.

METHODS

Eighty obese children were allocated evenly to four groups (20 in each group): groups I and II performed 20 -minute and 40-minute constant-load treadmill training, respectively, with the intensity set at running speed, corresponding to 100% of first ventilatory threshold (VT1), and groups III and IV performed 20 -minute and 40-minute training, respectively, with the intensity set at running speed, corresponding to 80% of VT1. Training was conducted every other day for eight consecutive weeks. Blood lipids,VO 2 max , and RPE were assessed pre- and postintervention.

RESULTS

Postintervention, significant between-group differences regarding all outcome measures (P<0.05) were indicated. Total cholesterol level had dropped significantly in group II compared to the other groups (adjusted P<0.05), and low-density lipoprotein and triglycerides had decreased significantly in group II compared to group III (adjusted P=0.003 and 0.007, respectively).VO 2 max had increased significantly in group II compared to group I (adjusted P=0.008). RPE had decreased significantly in group II in comparison to other groups (adjusted P<0.05).

CONCLUSION

Intensity and duration are essential factors in aerobic-exercise prescription to reduce cardiovascular risk factors, increase oxygen uptake, and improve perceived exertion in obese children.

Comparison of two warm-up models for obese and normal-weight adults performing supramaximal cycling exercise

This study examines the impact of two forms of active warm-up on supramaximal cycling performance among sedentary adults. Thirty-seven adults [23.05 (6.4) years; BMI=26.05 (1.3) kg/m², FM=30.1 (4.2)%, VO_2max=23.8 (5.8) ml/min/kg] participated in a cross-over randomized study, and all underwent a supramaximal cycling test (SCT) following 5 minutes of two models of warm-up pedalled at a constant velocity of 60 rpm. In the first experimental condition, the warm-up was set at 50% of maximal aerobic power (WU50%MAP). In the second experimental condition, the intensity was set at 50% of maximal heart rate (WU50%MHR). During both experimental conditions the rating of perceived exertion (RPE) at the end of the warm-up and the performance reduction in percentage (ΔPr%) during the SCT were recorded. During the WU50%MAP experimental condition, obese (OB) adults showed higher values of post-warm-up heart rate (~30%) than in the normal weight (NW) group (p<0.01). In addition, the RPE scores determined after the warm-up were significantly higher in OB compared to NW (~30%; p<0.01). However, after the WU50%MHR experimental condition, no significant differences remained between OB and NW. Moreover, the analyses showed a significant positive association between the elevated heart rate values observed after WU50%MAP and both RPE and ΔPr% (r= 0.71 and r =0.81, p <0.05 respectively). In contrast to NW individuals, the WU50%MHR seems to be more suitable for the OB group undergoing the SCT given that WU50%MAP affected supramaximal cycling performances.

The Effect of Body Mass Index on Acute Cardiometabolic Responses to Graded Exercise Testing in Children: A Narrative Review

Although the beneficial role of exercise for health is widely recognized, it is not clear to what extent the acute physiological responses (e.g., heart rate (HR) and oxygen uptake (VO₂)) to a graded exercise test are influenced by nutritional status (i.e., overweight vs. normal-weight). Therefore, the main objectives of the present narrative review were to examine the effect of nutritional status on acute HR, and VO₂ responses of children to exercise testing. For this purpose, we examined existing literature using PubMed, ISI, Scopus, and Google Scholar search engines. Compared with their normal-body mass index (BMI) peers, a trend of higher HRrest, higher HR during submaximal exercise testing, and lower HRmax was observed among overweight and obese children (according to BMI). Independent from exercise mode (walking, running, cycling, or stepping), exercise testing was metabolically more demanding (i.e., higher VO₂) for obese and overweight children than for their normal-weight peers. Considering these cardiometabolic differences according to BMI in children might help exercise specialists to evaluate the outcome of a graded exercise test (GXT) (e.g., VO2max, HRmax) and to prescribe optimal exercise intensity in the context of development of exercise programs for the management of body mass.

Intra-gastric balloon as an adjunct to lifestyle support in severely obese adolescents; impact on weight, physical activity, cardiorespiratory fitness and psychosocial well-being

BACKGROUND

Severe adolescent obesity (body mass index (BMI) >99.6th centile) is a significant public health challenge. Current non-invasive treatments, including community-based lifestyle interventions, are often of limited effectiveness in this population, with NICE guidelines suggesting the use of bariatric surgery as the last line of treatment. Health professionals are understandably reluctant to commission bariatric surgery and as an alternative, the use of an intra-gastric balloon as an adjunct to a lifestyle programme might offer a reversible, potentially safer and less invasive option.

OBJECTIVES

Explore the use of an intra-gastric balloon as an adjunct to a lifestyle support programme, to promote weight loss in severely obese adolescents. Outcomes included weight loss, waist and hip measurements, psychosocial outcomes including health-related quality of life (HRQoL) and physical self perceptions, physical activity and cardiorespiratory fitness.

METHOD

Non-randomised pilot study.

RESULTS

Twelve severely obese adolescents (5 males, 7 females; mean age 15 years; BMI >3.5 s.d.; puberty stage 4 or more) and their families were recruited. Mean weight loss at 12 months (n=9) was 3.05 kg±14.69; d=0.002, P=0.550, and a BMI Z-score (n=12) change of 0.2 s.d.; d=0.7, P=0.002 was observed at 6 months with a large effect, but was not sustained at 12 months (mean change 0.1 s.d.; d=0.3, P=0.146). At 24 months (n=10), there was a weight gain from baseline of +9.9 kg±1.21 (d=0.4; P=0.433). Adolescent and parent HRQoL scores exceeded the minimal clinical important difference between baseline and 12 months for all domains but showed some decline at 24 months.

CONCLUSION

An intra-gastric balloon as an adjunct to a lifestyle support programme represents a safe and well-tolerated treatment approach in severely obese adolescents, with short-term effects on weight change. Improvements in psychosocial health, physical activity and cardiorespiratory fitness were maintained at 12 months, with varying results at 24 months.

Exercise intolerance in obese children and adolescents

Background: Abnormal lung function has been reported in the obese population and is associated with the severity of obesity.

Objectives: To identify abnormal lung function in obese children and adolescents, and examine the cardiopulmonary response of those who have abnormal lung functions during exercise, and to reveal predictors of exercise intolerance in this population.

Methods: Fifty obese participants aged 8–18 years (56% male; mean age 13.2 ± 2.0 years; mean BMI 33.0 ± 3.6 kg/m2, mean BMI z score 3.1 ± 0.3) underwent spirometry, lung volume evaluation, and a cardiopulmonary exercise test.

Results: Lung function abnormalities and exercise intolerance because of pulmonary limitations were found in 36% and 74% of the participants, respectively. A comparison of participants with normal and abnormal lung functions revealed a lower breathing reserve and a higher ventilatory equivalent for CO2 production (VE/VCO2) during exercise in those who had lung function abnormalities (18 ± 15 vs 30±10%, P <0.001 and 30.3 ± 3.3 vs 29.6 ± 3.1; P = 0.02, respectively). Exercise intolerant participants had a higher BMI z score compared with those who were not (3.1 ± 0.3 vs 2.9 ± 0.3; P = 0.03). BMI z score ≥ 2.84 had an 80% sensitivity and 67% specificity for predicting exercise intolerance in this population.

Conclusions: Evaluations of lung function and exercise capacity should be included in the follow-up planning for obese children and adolescents. A BMI z score ≥ 2.84 was most sensitive for predicting exercise intolerance in this population.

Effects of Body Mass Index on Children's Physical Activity Levels in School-Based "Dance Dance Revolution"

OBJECTIVE

"Dance Dance Revolution" (DDR) (Konami Digital Entertainment, Inc., El Segundo, CA) has been recognized as an innovative approach to promote children's physical activity (PA). Previous works have described children's body mass index (BMI) status by group, but no studies have determined PA by category of BMI (underweight, normal weight, overweight, or obese). Therefore this study's purpose was to examine children's PA levels in DDR across different BMI groups.

MATERIALS AND METHODS

Participants were 160 third through sixth grade urban children (79 girls; 115 white) who participated in a weekly 30-minute DDR program for 18 weeks. Children's BMI was calculated based on height and weight. Levels of PA and sedentary behavior in DDR were assessed by ActiGraph(®) accelerometers (ActiGraph, LLC, Pensacola, FL) for three sessions. Outcome variables were percentages of time spent in sedentary behavior, light PA, and moderate-to-vigorous PA (MVPA).

RESULTS

Approximately one-third (32.5%) of children fell into the overweight (n = 26) or obese (n = 26) groups. One-way (overweight/obese versus normal weight) multivariate analysis of covariance with DDR skill level as covariate yielded a significant group effect (F3, 154 = 4.02, P < 0.01). Follow-up tests indicated normal weight children accumulated significantly more MVPA (F = 8.94, P < 0.01) but less sedentary behavior (F = 3.27, P = 0.07) and light PA (F = 3.77, P = 0.054) while playing DDR than overweight/obese children.

CONCLUSIONS

Overweight/obese children were less physically active than normal weight children during DDR. Consequently effective strategies are needed to stimulate these children to engage more actively in DDR experiences.

Cardiopulmonary Exercise Testing in Children and Adolescents with High Body Mass Index

Consensus has yet to be achieved on whether obesity is inexorably tied to poor fitness. We tested the hypothesis that appropriate reference of cardiopulmonary exercise testing (CPET) variables to lean body mass (LBM) would eliminate differences in fitness between high-BMI (≥ 95th percentile, n = 72, 50% female) and normal-BMI (< 85th percentile, n = 142, 49% female), otherwise-healthy children and adolescents typically seen when referencing body weight. We measured body composition with dual x-ray absorptiometry (DXA) and CPET variables from cycle ergometry using both peak values and submaximal exercise slopes (peak VO2, ΔVO2/ΔHR, ΔWR/ΔHR, ΔVO2/ΔWR, and ΔVE/ΔVCO2). In contrast to our hypothesis, referencing to LBM tended to lessen, but did not eliminate, the differences (peak VO2 [p < .004] and ΔVO2/ΔHR [p < .02]) in males and females; ΔWR/ΔHR differed between the two groups in females (p = .041) but not males (p = .1). The mean percent predicted values for all CPET variables were below 100% in the high-BMI group. The pattern of CPET abnormalities suggested a pervasive impairment of O2 delivery in the high-BMI group (ΔVO2/ΔWR was in fact highest in normal-BMI males). Tailoring lifestyle interventions to the specific fitness capabilities of each child (personalized exercise medicine) may be one of the ways to stem what has been an intractable epidemic.

Ventilatory Efficiency in Children and Adolescents: A Systematic Review

Introduction. The index of ventilatory efficiency (VE/VCO₂) obtained by the progressive exercise test has been considered the gold standard in the prognosis of adults with heart failure, but few studies have evaluated this approach in children. Objective. To verify the scientific evidence about the VE/VCO₂ in pediatric and adolescents patients. Methods. A systematic literature review was carried out using the key words VE/VCO₂, children, and adolescents using the PEDro and PubMed/MedLine databases. Clinical trials published from 1987 to 2014, including children, adolescents, and young adults up to 25 years, addressing the VE/VCO₂ index as a method of evaluation, monitoring, and prognosis were considered. Results. Initially, 95 articles were found; 12 were excluded as the title/abstract did not contain the VE/VCO₂ index or because they included patients greater than 25 years of age. From the remaining 83, 58 were repeated between the databases. The final sample consisted of 32 studies including healthy children and children with respiratory and other diseases. Conclusion. There are few studies involving cardiorespiratory assessment by ventilatory efficiency. The studies highlight the fact that high VE/VCO₂ values are associated with a worse prognosis of patients due to the relationship with the decrease in pulmonary perfusion and cardiac output.

Attentional distraction during exercise in overweight and normal-weight boys

The purpose of this study was to investigate the effect of attentional distraction on field running distance and activity intensity during an exercise session in normal-weight and overweight youngsters and to investigate potential mediators. Fifty-three 12–14 yr-old boys participated twice in a 12-min running test and a 20-min exercise session, once with attentional distraction (by listerning to music) and once without distraction (counterbalanced randomised controlled design). At the end of the endurance test running distance was recorded. During the exercise session activity intensity was assessed by accelerometers. After each experiment, rate of perceived exertion (RPE) was estimated and seven questions were asked about how participants experienced the experiment. Both overweight and normal-weight boys ran further during the running test with music (p < 0.05) and this effect was mediated by a decrease in feelings of annoyance. During the exercise session with music, both overweight and normal-weight boys exercised less at low and high intensity and more at moderate and very high intensity (p < 0.01) and this effect was mediated by a decrease in RPE. We can conclude that attentional distraction has a positive effect on running distance on a field endurance test and on activity intensity during an exercise session through different mechanisms in both overweight and normal-weight boys.

Exercise tolerance in obese vs. lean adolescents: a systematic review and meta-analysis

To prescribe feasible and medically safe exercise interventions for obese adolescents, it remains to be determined whether exercise tolerance is altered and whether anomalous cardiopulmonary responses during maximal exercise testing are present. Studies that examined cardiopulmonary responses to maximal exercise testing in obese adolescents were searched: cardiopulmonary exercise tests with respiratory gas exchange measurements of peak oxygen uptake (VO2peak) were performed and comparisons between obese and lean adolescents were made. Study quality was assessed using a standardized item list. By meta-analyses VO2peak, peak cycling power output (Wpeak) and peak heart rate (HRpeak) were compared between groups. Nine articles were selected (333 obese vs. 145 lean adolescents). VO2peak (L min(-1)), HRpeak and Wpeak were not different between groups (P ≥ 0.10), while a trend was found for a reduced VO2peak (mL min(-1) kg(-1) lean tissue mass) (P=0.07) in obese vs. lean adolescents. It remained uncertain whether anomalous cardiopulmonary responses occur during maximal exercise testing in obese adolescents. In conclusion, a trend was found for lowered VO2peak (mL min(-1)kg(-1) lean tissue mass) in obese vs. lean adolescents. Whether cardiopulmonary anomalies during maximal exercise testing would occur in obese adolescents remains uncertain. Studies are therefore warranted to examine the cardiopulmonary response during maximal exercise testing in obese adolescents.

Direct and self-reported measures of physical activity and sedentary behaviours by weight status in school-aged children: results from ISCOLE-Kenya

BACKGROUND

Previous work has shown little association between self-report and directly measured physical activity. The objective of this study was to investigate the relationships between self-reported and directly assessed measures of physical activity and sedentary time by weight status in Kenyan children.

METHODS

Direct assessment of body weight, physical activity and sedentary time of 563 children was collected through anthropometry and accelerometry, while self-reported assessment was achieved by administering a questionnaire.

RESULTS

Under/healthy weight children had significantly higher directly measured mean daily minutes of moderate-to-vigorous physical activity (MVPA) compared to overweight/obese children (39 vs 20 minutes); had lower mean weekend-day minutes of sedentary time (346 vs 365 minutes); had a higher proportion who met accepted physical activity guidelines (15.3% vs 2.6%); and a higher number reported using active transportation to/from school (49.2% vs 32.4%). Self-reported time spent outside before and after school and active transport to/from school were significantly associated with mean weekday minutes of MVPA (r-value range = 0.12-0.36), but only for the under/healthy weight children.

CONCLUSIONS

The results of this study found a number of differences in the accumulation of MVPA and sedentary time by weight status and weak-to-moderate correlations between self-report and direct measures of weekday and weekend-day physical activity among the under/healthy weight children.

Physiological response is similar in overweight and normoweight boys during cycling: a longitudinal study

The purpose of this study was to determine whether metabolic cost is similar in overweight and normoweight children when workload during exercise on a cycle-ergometer is adjusted relative to an objectively determined second ventilatory threshold (VT2) or the maximal workload (Pmax). The tests were conducted every 2 years: first at the age of 10 years and the third test at around the age of 14 years. The levels of maximal oxygen consumption (VO(2)max), Pmax, and the VT2 were determined by means of graded tests on a cycle ergometer. The main test consisted of two 6-minute exercises of submaximal constant intensity (below and above VT2) performed on a cycle ergometer, with a 4-minute recovery between efforts. The workload during cycling was adjusted individually for each participant and adjusted to the values determined in the graded test: workload at VT2 and Pmax. Physiological response (absolute and relative to free-fat mass oxygen uptake, heart rate, pulmonary ventilation, tidal volume, and breathing frequency) is similar in overweight and normoweight boys when workload on a cycle ergometer is adjusted to VT2. The only significant intergroup difference was seen in relative to body mass oxygen intake.

Exercise training improves breathing strategy and performance during the six-minute walk test in obese adolescents

OBJECTIVES

We aimed to examine ventilatory responses during the six-minute walk test in healthy-weight and obese adolescents before and after exercise training.

METHODS

Twenty obese adolescents (OB) (age: 14.5±1.7 years; BMI: 34.0±4.7kg·m(-2)) and 20 age and gender-matched healthy-weight adolescents (HW) (age: 15.5±1.5 years; BMI: 19.9±1.4kg·m(-2)) completed six-minute walk test during which breath-by-breath gas analysis and expiratory flow limitation (expFL) were measured. OB participated in a 12-week exercise-training program.

RESULTS

Comparison between HW and OB participants showed lower distance achieved during the 6MWT in OB (-111.0m, 95%CI: -160.1 to 62.0, p<0.05) and exertional breathlessness was greater (+0.78 a.u., 95%CI: 0.091-3.27, p=0.039) when compared with HW. Obese adolescents breathed at lower lung volumes, as evidenced by lower end expiratory and end inspiratory lung volumes during exercise (p<0.05). Prevalence of expFL (8 OB vs 2 HW, p=0.028) and mean expFL (14.9±21.9 vs 5.32±14.6% VT, p=0.043, in OB and HW) were greater in OB. After exercise training, mean increase in the distance achieved during the 6MWT was 64.5 meters (95%CI: 28.1-100.9, p=0.014) and mean decrease in exertional breathlessness was 1.62 (95%CI: 0.47-2.71, p=0.05). Obese adolescents breathed at higher lung volumes, as evidenced by the increase in end inspiratory lung volume from rest to 6-min exercise (9.9±13.4 vs 20.0±13.6%TLC, p<0.05). Improved performance was associated with improved change in end inspiratory lung volume from rest to 6-min exercise (r=0.65, p=0.025).

CONCLUSION

Our results suggest that exercise training can improve breathing strategy during submaximal exercise in obese adolescents and that this increase is associated with greater exercise performance.

Effect of exercise test on pulmonary function of obese adolescents

OBJECTIVE

to investigate the pulmonary response to exercise of non-morbidly obese adolescents, considering the gender.

METHODS

a prospective cross-sectional study was conducted with 92 adolescents (47 obese and 45 eutrophic), divided in four groups according to obesity and gender. Anthropometric parameters, pulmonary function (spirometry and oxygen saturation [SatO2]), heart rate (HR), blood pressure (BP), respiratory rate (RR), and respiratory muscle strength were measured. Pulmonary function parameters were measured before, during, and after the exercise test.

RESULTS

BP and HR were higher in obese individuals during the exercise test (p = 0.0001). SatO2 values decreased during exercise in obese adolescents (p = 0.0001). Obese males had higher levels of maximum inspiratory and expiratory pressures (p = 0.0002) when compared to obese and eutrophic females. Obese males showed lower values of maximum voluntary ventilation, forced vital capacity, and forced expiratory volume in the first second when compared to eutrophic males, before and after exercise (p = 0.0005). Obese females had greater inspiratory capacity compared to eutrophic females (p = 0.0001). Expiratory reserve volume was lower in obese subjects when compared to controls (p ≤ 0,05).

CONCLUSION

obese adolescents presented changes in pulmonary function at rest and these changes remained present during exercise. The spirometric and cardiorespiratory values were different in the four study groups. The present data demonstrated that, in spite of differences in lung growth, the model of fat distribution alters pulmonary function differently in obese female and male adolescents.

Evaluation of cardiorespiratory fitness and respiratory muscle function in the obese population

Cardiorespiratory fitness (CRF) is one of the most important health metrics in apparently healthy individuals, those at increased risk for cardiovascular (CV) disease and virtually all patient populations. In addition to CRF, a host of other variables obtained from aerobic exercise testing provides clinically valuable information. Individuals classified as obese (i.e. a body mass index ≥30 kg/m(2)) have varying degrees of CV, pulmonary and skeletal muscle dysfunction that impact CRF and other key aerobic exercise testing variables. Moreover, there is now evidence indicating inspiratory and expiratory respiratory muscle function, even in the absence of interstitial lung disease, is potentially compromised as a result of obesity. When obesity-induced respiratory muscle dysfunction is present, it has the potential to contribute to the limitations in CRF. The current review will discuss aerobic exercise testing and the assessment of respiratory muscle function in the obese population.

Do obese children perceive submaximal and maximal exertion differently?

We examined how obese children perceive a maximal cardiorespiratory fitness test compared with a submaximal cardiorespiratory fitness test. Twenty-one obese children (body mass index ≥95th percentile, ages 10-17 years) completed maximal and submaximal cardiorespiratory fitness tests on 2 separate occasions. Oxygen consumption (VO2) and overall perceived exertion (Borg 15-category scale) were measured in both fitness tests. At comparable workloads, perceived exertion was rated significantly higher (P < 0.001) in the submaximal cardiorespiratory fitness test compared with the maximal cardiorespiratory fitness test. The submaximal cardiorespiratory fitness test was significantly longer than the maximal test (14:21 ± 04:04 seconds vs. 12:48 ± 03:27 seconds, P < 0.001). Our data indicate that at the same relative intensity, obese children report comparable or even higher perceived exertion during submaximal fitness testing than during maximal fitness testing. Perceived exertion in a sample of children and youth with obesity may be influenced by test duration and protocol design.

Expiratory flow limitation and breathing strategies in overweight adolescents during submaximal exercise

OBJECTIVE

To investigate whether ventilatory factors limit exercise in overweight and obese children during a 6-min step test and to compare ventilatory responses during this test with those of healthy weight children.

DESIGN

Cross-sectional, prospective comparative study.

SUBJECTS

Twenty-six overweight/obese subjects and 25 healthy weight subjects with no known respiratory illness.

MEASUREMENTS

Various fatness and fat distribution parameters (using air displacement plethysmography and anthropometry), pulmonary function tests, breath-by-breath gas analysis during exercise, perceived exertion.

RESULTS

Young people who are overweight or obese are more likely to experience expiratory flow limitation (expFL) during submaximal exercise compared with their healthy weight peers [OR 7.2 (1.4, 37.3), P=0.019]. Subjects who had lower lung volumes at rest were even more likely to experience exercise-induced expFLs [OR 8.35 (1.4-49.3)]. Both groups displayed similar breathing strategies during submaximal exercise.

CONCLUSION

Young people who are overweight/obese are more likely to display expFL during submaximal exercise compared with children of healthy weight . Use of compensatory breathing strategies appeared to enable overweight children to avoid the experience of breathlessness at this intensity of exercise.

Pulmonary function and exercise capacity in children following lung resection surgery

PURPOSE

To study lung function and exercise capacity in children following lung resection surgery.

METHODS

Children aged 6-18 years who had lung resection surgery were studied and compared to normal children (age and sex matched). All had spirometry/body plethysmography and exercise stress test (performed by treadmill and modified Balke protocol).

RESULTS

13 Patients and 13 controls were studied (age 13.2 ± 3.3 years; 46.2 % male). The age at the time of lung resection surgery was 6.5 ± 4.7 years. The time interval between post-surgery and the tests was 6.8 ± 4.4 years. The most common indication for lung resection surgery was congenital lung malformations (61.5 %). 76.9 % of the patients had abnormal lung function. Exercise intolerance due to pulmonary limitations was found in 23.1 % of the patients. At the anaerobic threshold, the V(O2) was not different between the patients and the controls. However, at the end of the exercise, the patients demonstrated lower peak V(O2) than the controls (33.6 ± 6.0 vs. 39.3 ± 8.7 ml/min/kg; p < 0.01).

CONCLUSIONS

Abnormal lung functions and exercise intolerance were found in children following lung resection surgery. Children who had lung resection surgery had lower exercise capacity than normal children if the exercise was beyond the anaerobic threshold.

Differential accuracy of physical activity self-report by body mass index

OBJECTIVES

To examine whether agreement between self-reported and accelerometer-measured physical activity varies by BMI category in a low-income black sample.

METHODS

Participants completed a questionnaire and wore an accelerometer for 4-6 days. Using one- and 10-minute bouts, accelerometers measured light, moderate, and vigorous physical activity time.

RESULTS

Correlations varied by obesity (nonobese: one-minute r=0.41; 10-minute r=0.47; obese: one-minute r=0.21; 10-minute r=0 .14). Agreement was highest among nonobese persons (one-minute kappa = 0.48, 10-minute kappa = 0.023; obese: one-minute kappa = -0.024, 10- minute kappa = -0.020).

CONCLUSIONS

We found compromised questionnaire performance among obese participants.

Peak oxygen uptake correlates with survival without clinical deterioration in ambulatory children with dilated cardiomyopathy

BACKGROUND

Children stable at home with dilated cardiomyopathy remain at risk of death; there is evidence of survival benefit for transplantation out to 4 years postoperatively. The limited supply of donor organs makes risk stratification imperative, but although cardiopulmonary exercise test is well established as a powerful tool in adults with heart failure, no published studies have linked oxygen uptake to prognosis in children.

METHODS AND RESULTS

Between 2001 and 2009, using cardiopulmonary exercise test and echocardiography, we studied 82 children (mean age, 13.5±2.3 years) with dilated cardiomyopathy. All were ambulatory, outpatients, and >120 cm in height. All children completed a symptom-limited maximal exercise test. Resting left ventricular shortening fraction was 20±9%; peak heart rate was 87±13% of predicted; peak oxygen uptake (VO(2)) was 67±22% of predicted; and ventilatory efficiency was 32±8. Follow-up was available for 100% of the children, and was a mean of 32.3±7.5 months. Eighteen patients reached the defined clinical end point of death or listing for urgent heart transplantation. On univariate analysis, left ventricular shortening fraction, peak heart rate, peak VO(2), peak systolic blood pressure, and ventilatory efficiency were all associated with adverse outcome. On multivariable Cox analysis, only peak VO(2) (P=0.003) was associated with the study end point. Patients with a peak VO(2) ≤62% of predicted had a higher 24-month event rate (50.6% versus 4.4%; hazard ratio, 10.78).

CONCLUSIONS

We have demonstrated that a cardiopulmonary exercise test is feasible in ambulatory children with dilated cardiomyopathy who are >120 cm height and for the first time have linked peak VO(2) with outcome in children.

Lifestyle and the Respiratory Health of Children

This article offers a review of the potential influences of personal lifestyle on respiratory health in children, looking at both healthy individuals and those with respiratory disorders. As with many aspects of health, regular physical activity, an appropriate diet, and avoidance of obesity and cigarette smoke all contribute to optimal development of the healthy child. An active lifestyle is associated with greater static and dynamic lung volumes, greater efficiency of the ventilatory process, and an optimization of breathing patterns. The risk of upper respiratory infections is also reduced in those maintaining a moderate level of physical activity. Maternal smoking during pregnancy, as well as active and passive smoking, all have an adverse influence on lung function in the child, the largest effects being on dynamic lung volumes. The risk of developing asthma seems reduced in children who maintain a normal body mass and are physically active. A program of graded physical activity is of therapeutic value in a number of established respiratory conditions, including asthma, cystic fibrosis, and ventilatory impairment from neuromuscular disorders. Exercise carries a slight risk of fatalities from asthma and anaphylactic reactions. In designing an optimal physical activity program, it is also important to guard against the hazards of deep oronasal breathing, including the precipitation of bronchospasm by the inhalation of cold, dry air and pollens; an increased exposure to atmospheric pollutants (reducing and oxidant smog, fine and ultra-fine particulates, and carbon monoxide); and possible long-term dangers from chlorine derivatives in the atmosphere of indoor swimming pools.

Obesity: the new childhood disability?

This review addresses the impact of obesity on paediatric physical functioning utilizing the World Health Organization International Classification of Functioning, Disability and Health Framework (ICF). The ICF encompasses functioning (as it relates to all body functions and structures), activities (undertaking a particular task) and participation (in a life situation) with disability referring to impairments in body functions/structures, activity restrictions or participation limitations. Electronic databases were searched for peer-reviewed studies published in English prior to May 2009 that examined aspects of physical functioning in children (≤18 years). Eligible studies (N = 104) were ranked by design and synthesized descriptively. Childhood obesity was found to be associated with deficits in function, including impaired cardiorespiratory fitness and performance of motor tasks; and there was some limited evidence of increased musculoskeletal pain and decrements in muscle strength, gait and balance. Health-related quality of life and the subset of physical functioning was inversely related to weight status. However, studies investigating impacts of obesity on wider activity and participation were lacking. Further research utilizing the ICF is required to identify and better characterize the effects of paediatric obesity on physical function, activity and participation, thereby improving targets for intervention to reduce disability in this population.

Comparação das variáveis cardiorrespiratórias de adolescentes obesos e não obesos em esteira e bicicleta ergométrica

O objetivo deste estudo foi investigar o consumo máximo de oxigênio (VO2max) em adolescentes obesos e não obesos em esteira e bicicleta ergométrica. O estudo foi transversal e descritivo com a amostra de 54 indivíduos obesos (23 meninos e 31 meninas) e 33 não obesos (16 meninos e 17 meninas) com idade entre 10 e 16 anos. Utilizou-se o critério dos Centers for Disease Control and Prevention (CDC, 2000) para a classificação do índice de massa corporal (IMC). Foram avaliados o peso, estatura, índice de massa corporal (IMC) e IMC-escore Z. Para avaliação cardiorrespiratória foi realizado teste máximo em esteira e bicicleta ergométrica. Foram avaliados a frequência cardíaca máxima (FCmax), coeficiente respiratório (RER), consumo máximo de oxigênio (VO2max), tempo total de teste (TT) e carga final (w) na bicicleta ergométrica. Utilizou-se o teste de t de Student para a comparação dos ergômetros. Nas análises dos grupos, utilizou-se a ANOVA fatorial. Considerou-se significante p < 0,05. Os resultados revelaram que o peso, IMC e IMC-escore Z foram maiores nos obesos. Os valores de VO2max absoluto (l.min-1) foram mais altos nos obesos, em ambos os gêneros, na esteira, sem diferenças entre os grupos na bicicleta. Entretanto, o VO2max relativo ao peso corporal (ml.kg-1.min-1) foi menor no grupo obeso e nas meninas, em ambos os ergômetros. A carga de trabalho na bicicleta foi similar entre os obesos e não obesos. Concluiu-se que os obesos apresentaram valores de VO2max mais baixos que os não obesos em ambos os ergômetros. Entretanto, o fato de o indivíduo obeso na bicicleta suportar a mesma carga final que o não obeso sugere-se que a bicicleta pode ser indicado como o melhor ergômetro para obesos.

Do overweight girls overreport physical activity?

OBJECTIVE

To determine if overweight adolescent girls are more likely to overreport physical activity compared to normal-weight girls.

METHODS

Participation in physical activities and perceived intensity of activities were assessed from the previous day physical activity recall (PDPAR) in 1021 girls aged 11-14 years old (37% overweight). Daily minutes of moderate to vigorous physical activity (MVPA) were measured using accelerometry.

RESULTS

Girls in the "at-risk for overweight" and "overweight" categories had 17.7% and 19.4% fewer minutes of MVPA per block reported on the PDPAR compared to normal-weight girls (P<0.05).

CONCLUSIONS

Overweight adolescent girls tend to overreport their total amount of physical activity.