Relationship between quality of life, physical activity, screen time and cardiorespiratory fitness in children

1.INTRODUCTION:

The evidence of the benefits of physical activity and cardiovascular fitness on the physical health and quality of life is well documented. These benefits include a reduced risk of coronary heart disease, hypertension, and type II diabetes (13). Health related quality of life (HRQoL) is a resource for adaptation and healthy growth. When HRQoLdiminishes, a child is less likely to be able to develop normally and mature into a healthy adult (18).The frequency, duration and intensity of physical activity necessary to confer these various benefits in children remain the subject of debate, although the general consensus is for children and youth to accumulate an average of at least 60 minutes per day and up to several hours of at least moderate intensity, and aerobic activities should make up the majority of the physical activity (7).There is a recognized need to consider the effect of habitual physical activity on children’s quality of life(14). Previous studies have shown that lifestyles are associated with mental and health status, as well as HRQoL in adults, but there is no consensus about the effect of physical activity on the different determinants of HRQoL in children (3), (5). Beyond physical activity, physical fitness is nowadays considered one of the most important health markers, as well as a predictor of morbidity and mortality for cardiovascular disease (1). Childhood and adolescence are crucial periods of life and improvement in cardiorespiratory fitness seem to positively affect depression status, and self-esteem, this improvement is required for an enhanced psychological well-being. In this regard the literature in young people is rather scarce (13). The negative effects of sedentary lifestyles on children’s health is also a source of concern, the increasing prevalence of obesity among developed countries coincides with an increasing prevalence of high screen time (defined as a combination of activities such a watching television or playing video games). (2), (9). The American Academy of Pediatrics recommends that children’s screen time be limited to no more than 1 to 2 hours per day. Social cognitive theory posits that sedentary behavior is influenced by personal beliefs, physical characteristics, and other related behaviors (frequency or regular participation in physical activity). Empirical research has demonstrated support for these relationships with respect to screen time (8). TV viewing also predicts lower fitness, but not higher Body Mass Index (BMI) (12), this is an important finding because cardiorespiratory fitness (CRF) is one of the most important targets in preventing childhood obesity. There is also evidence that a strong relationship between physical activity (PA) levels and metabolic risk exists in children with low CRF (13). 36 The links between obesity and HRQoL have been less studied, and limited research exists linking youth obesity to poorer youthHRQoL, it appears likely that increasing weight status has a moderate to strong negative influence on HRQoL in pediatric populations, whereby decrements of in HRQoL are evident as soon as BMI is above the healthy normal limits (21), youth overweight showed significant positive association to adult HRQoL, however no associations have been found between youth PA and adult mental or physical HRQoL (5). The aim of this study was to examine the association between different factors of quality of life, and anthropometric measures, levels of physical activity, cardiorespiratory fitness and sedentary behaviors in children.

2.METHODS.

2.1. Participants and Data Collection

A cross sectional study was performed in the Balearic Islands (west coast of Spain) as a part of the SAFE project (an school based global intervention to promote healthy habits in school age children). The study was conducted between March and April 2009. The target group consisted of children aged between 10 and 12 years (5th-6th grades) from 244 regional elementary schools. The study included 302 participants (151 boys and 151 girls) from 64 randomly selected schools. Children and their families received written information about purposes and the content of the study. Before the study began all parents, teachers and managers of schools approved the study protocol, and all parents signed an informed consent. The Ethical Committee from the University of the Balearic Islands approved this study. The study collects information about levels of physical activity, physical inactivity (screen time) and physical fitness, as well as collects the information of the Health related Quality of Life reported by their parents.

2.2. Assessment of Health Related Quality of Life

The Spanish version of the Child Health and Illness Profile-Child Edition /Parent Report Form (CHIP-CE/PRF) (4) was used to evaluate Health related Quality of Life. This instrument (17) collects parent reported health information about children aged 6-12 years. The CHIP is based on a broadly defined conceptual framework which recognizes that health includes not only perceptions of wellbeing, illness and health, but also participation developmentally appropriated tasks and activities, originally this instrument include 5 domains, in this study we have used four domains to shorten the time of the questionnaire (16); Satisfaction with health, Physical comfort, Emotional comfort and restricted activity. Satisfaction with health assesses overall perception of well being (this is a positive scale, i.e. the higher the score the higher the level of satisfaction with health). Physical comfort includes parents’ assessment of the child’s experience of physical symptoms (this is a negative scale, i.e. the higher the score the lower the level of physical comfort). Emotional comfort assesses parent’s experience of emotional symptoms like crying, fear, and sadness (this is a negative scale, i.e. the higher the score the lower 37 the level of emotional comfort). Restricted activity assesses parents’ experience and observed limitation of their offspring to carry out some activities (this is a positive scale, the higher the score the higher the limitation of activities).

2.3. Assessment of Physical Activity and Screen Time

The School Health Action, Planning and Evaluation System (SHAPES) physical activity questionnaire (22), consists of 45 multiple choice questions, items request 7 day recall of moderate to vigorous physical activity, but not only to measure self-reported physical activity levels but inform about participation in physical activities, sedentary activities (Watching TV, playing videogames, homework), social influences (e.g., parent and peer influences), and school environment for children 11-16 years old.

2.4. Assessment of Cardio-Respiratory Fitness

Cardio-Respiratory fitness was assessed with the 20m shuttle run test (20mSRT) from the ALPHA Health related fitness test battery for children and adolescents, (19) recently validated and can be considered both valid and reliable to assess cardio-respiratory fitness and seems to be the best one in estimate Vo2max in children and adolescents.

2.5. Statistical Analysis

Descriptive statistics (means and standard deviations) were calculated for all anthropometric characteristics physical fitness, physical activity and sedentary behaviors (screen time) according to gender group. The strength of the association between HRQoL domains and outcomes was characterized by Pearson correlation. The level of significance was set at p< .05. Data were analyzed using SPSS for Apple Mac, version 19.0 (SPSS Inc., Chicago, IL)

3. RESULTS.

The subjects in the study (151 boys and 151 girls) are a standard population, table 1, shows both average BMI in a percentile 75 compared to CDC grow charts, and average level of physical activity and also a cardiorespiratory fitness average for this population.

Table 1. Descriptive data for boys and girls.

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Gráfico 2. Nivel de sobrepeso en relación con el tipo de deporte practicado (federado / no federado)

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Table 2 shows the relation between Health related quality of life domains (satisfaction physical comfort, emotional comfort and restricted activity) with levels of physical activity; screen time, cardiorespiratory fitness and BMI. Our findings suggest that there is no relation with quality of life and physical activity in children in neither of the domains used in the HRQoL questionnaire. Screen time, as a accepted measure for the sedentary lifestyle is highly associated with one of the domains of quality of life, restricted activity, but is negatively associated with physical comfort. Cardiorespiratory fitness is associated with quality of life in the domain of physical comfort, and BMI is negatively associated with restricted activity. There was no evidence of sex-interactions and stratified analyses by gender showed similar patterns in boys and girls (data not shown).

Table 2. Health related Quality of Life domains relationship with Physical activity, sedentary behaviors, cardio-respiratory fitness and Anthropometric measures.

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As a secondary analysis the influence of the active friends was a interesting field of evaluation, table 3 shows the relationship between the quality of life domains and peer influence.Active friends have a positive association with these overall well being. Active friends, have also a positive association with limitation of activities.

Table 3. Relationship between the quality of life domains and peerinfluence.

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4. DISCUSSION

This study aimed to examine the relationship between quality of life domains reported by parents through CHIP-CE/PRF with levels of physical activity, screen time, BMI, and cardio respiratory fitness of their children. The most important outcome of this study was the result showed that cardio respiratory fitness predicts quality of life (Physical comfort) this domain of quality of life assesses the physical symptoms (in a negative scale score) our findings suggest that a better cardiorespiratory fitness level predicts less disease symptoms like pain, fever, mucus, headache, stomachache… among others, on the contrary, there is no association between physical activity and quality of life in the children in our study. Screen time is associated with restricted activity, more screen time leads to more limitation of activities like being too sick to play or being too sick to go to school. One unexpected finding of this study is the association between BMI and restricted activity; our findings suggest that there is a negative association between this anthropometric measure and less limitation for activities Another unexpected outcome of this study is the association between screen time and physical comfort, our findings suggest that the children of this study who spend more time in front of a TV, computer or videogames have less symptoms of disease There is limited research linking HRQoL to physical activity in children and Scarce literature linking Physical fitness to HRQoL, our research confirm the findings about the BMI and physical activity associated with better or worse quality of life(20),who reported positive associations between BMI and HRQoL, and no associations were found between Physical activity and HRQoL(5). Our findings confirm the hypothesis that Fitness has a positive association with HRQoL but no positive associations to Physical activity. The key point, is the intensity of physical activity reported in the questionnaires, Physical activity need a 41 vigorous intensity to causes changes in fitness, and is in this moment that affects the whole body not only affecting the energy balance but providing the subject significant adaptations to their body. HRQoLis also positively associated with active friends, Analyzing the peer influences, our findings show some associations with active friends and HRQoL (satisfaction with health and restricted activity), the association of active friends with overall well being support the idea that quality of life includes not only perceptions of well-being, illness and health, but also participation developmentally appropriated tasks and activities, and the relations with relatives and friends, confirming results from studies relating environmental and peer influences in physical activity and fitness (10). The findings of this study are important due to many lifestyle habits are established during childhood, physical activity and exercise habits may also be established during this years, but with an orientation to improve Physical fitness, otherwise it will be a good activity to increase energy expenditure (6) but will not achieve the main objective, improving children’s health. Limitations should be recognized. First the small sample size, and therefore results should be interpreted with caution due to underpowered data. Self-report physical activity is also a limitation, but results indicate similar PA levels to other studies with objective measures. In third place, cardiorespiratory fitness were assessed indirectly although, 20m shuttle run test, is included in the majority of fitness batteries around the world, and is considered a valuable tool for studying CRF in young healthy children. Strength of this study is its original approach to the Health related quality of life from the Physical fitness perspective, which allowed us to confirm the hypothesis that fitness is a powerful and relevant marker of health. These findings are important because they provide a field of future research in the relationship between physical fitness and HRQoL in children.

CONCLUSION

In conclusion, this study examined the association between HRQoL and CRF, PA, Screen time and BMI, and the results suggest that Cardio Respiratory Fitness and Screen time have significant association with some quality of life domains but not Physical activity.

ACKNOWLEDGMENT

This study was supported by grant: JC2010-245 from the Spanish Ministry of Education.