Emma Eyre

The influence of age and weight status on cardiac autonomic control in healthy children: a review.

Heart rate variability (HRV) analyses can provide a non-invasive evaluation of cardiac autonomic activity. How autonomic control normally develops in childhood and how this is affected by obesity remain incompletely understood. In this review we examine the evidence that childhood age and weight status influence autonomic control of the heart as assessed using HRV. Electronic databases (Pubmed, EMBASE and Cochrane Library) were searched for studies examining HRV in healthy children from birth to 18 years who adhered to the Task Force (1996) guidelines. Twenty-four studies met our inclusion criteria. Seven examined childhood age and HRV. A reduction in 24-hour LF:HF was reported from birth to infancy (1 year), while overall HRV (SDNN) showed a marked and progressive increase. From infancy to early-to-late childhood (from 12 months to 15 years) LF:HF ratio was reported to decline further albeit at a slower rate, while RMSSD and SDNN increased. Twenty studies examined the effects of weight status and body composition on HRV. In a majority of studies, obese children exhibited reductions in RMSSD (n = 8/13), pNN50% (n = 7/9) and HF power (n = 14/18), no difference was reported for LF (n = 10/18), while LF:HF ratio was elevated (n = 10/15). HRV changes during childhood are consistent with a marked and progressive increase in cardiac parasympathetic activity relative to sympathetic activity. Obesity disrupts the normal maturation of cardiac autonomic control.

The Effect of Green Exercise on Blood Pressure, Heart Rate and Mood State in Primary School Children

The aim of this study was exploratory and sought to examine the effect on blood pressure (BP), heart rate (HR) and mood state responses in primary school children of moderate intensity cycling whilst viewing a green environment compared to exercise alone. Following ethics approval and parental informed consent, 14 children (seven boys, seven girls, Mean age ± SD = 10 ± 1 years) undertook two, 15 min bouts of cycling at a moderate exercise intensity in a counterbalanced order. In one bout they cycled whilst viewing a film of cycling in a forest setting. In the other condition participants cycled with no visual stimulus. Pre-, immediately post-exercise and 15 min post-exercise, BP, HR and Mood state were assessed. Analysis of variance, indicated significant condition X time interaction for SBP (p = 0.04). Bonferroni post-hoc pairwise comparisons indicated that systolic blood pressure (SBP) 15 min post exercise was significantly lower following green exercise compared to the control condition (p = 0.01). There were no significant differences in diastolic blood pressure (DBP) (all p > 0.05). HR immediately post exercise was significantly higher than HR pre exercise irrespective of green exercise or control condition (p = 0.001). Mood scores for fatigue were significantly higher and scores for vigor lower 15 min post exercise irrespective of green exercise or control condition (both p = 0.0001). Gender was not significant in any analyses (p > 0.05). Thus, the present study identifies an augmented post exercise hypotensive effect for children following green exercise compared to exercise alone.

Objectively measured patterns of physical activity in primary school children in Coventry: the influence of ethnicity

The aetiology of increased metabolic risk in South Asians is incompletely understood, but may include modifiable factors such as physical activity. This study assessed patterns of physical activity in UK primary school children and examined the influence of ethnicity.

The Impact of Ethnicity on Objectively Measured Physical Activity in Children

Obesity and obesity-related diseases (cardiovascular disease/metabolic risk factors) are experienced differently in individuals from different ethnic backgrounds, which originate in childhood. Physical activity is a modifiable risk factor for obesity and related diseases. Both physical activity and metabolic risk factors track to adulthood, and thus understanding the physical activity patterns in children from different ethnic backgrounds is important. Given the limitations of self-report measures in children, this study provides a review of studies which have objectively measured physical activity patterns in children from different ethnic backgrounds. From a total of 16 studies, it can be concluded that physical activity does seem to vary amongst the ethnic groups especially South Asian and Black compared to White EU (European Union). The findings are less consistent for Hispanic/Mexican American children. However, there are several methodological limitations which need to be considered in future studies. Firstly, there is a need for consistency in the measurement of physical activity. Secondly, there are a range of complex factors such as socioeconomic status and body composition which affect both physical activity and ethnicity. Studies have failed to account for these differences limiting the ability to generalise that ethnicity is an independent risk factor for physical activity.

Low socio-economic environmental determinants of children's physical activity in Coventry, UK: a qualitative study in parents

Background Childrens physical activity (PA) is affected by socio-economic status (SES) and the environment. Children are not fully autonomous in their decision making; parental decisions thus affect how children utilise their surrounding environments for PA. The aim was to examine environmental influences on childrens PA from a qualitative perspective in parents from low SES wards in Coventry, UK. Method 59 parents of children in year 4 (aged 8–9years) completed the ALPHA environmental questionnaire. 16 of these parents took part in focus group discussions examining environmental facilitators and barriers to their childs PA (March–April, 2013). Results Emerging themes related to physical (i.e. poor access, safety and quality of the neighbourhood) and social environment (i.e. ‘rough’ neighbourhood due to crime and anti-social behaviour) influences on the PA behaviour of children. The parents believed these environmental factors resulted in the children engaging in greater sedentary activity (watching TV) indoors. The school environment was perceived as a supportive physical environment for childrens PA behaviour. Conclusion Parents perceptions of an unsupportive physical and social environment restrict childrens opportunities to play outside and be physically active and may lead to increased body fat (BF). Schools provide a supportive environment for children from low SES to be physically active in.

The impact of a school-based gardening intervention on intentions and behaviour related to fruit and vegetable consumption in children

A total of 77 children (34 boys, 43 girls, mean age ± standard deviation = 9 ± 1 years) participated in this study; 46 children (intervention) undertook a 12-week school gardening programme and 31 children acted as controls. Measures of the Theory of Planned Behaviour and fruit and vegetable consumption were taken pre- and post-intervention. Repeated measures analysis of variance and hierarchical regression analysis indicated that the intervention group increased daily consumption of fruits and vegetables and increased intentions, attitudes, norms, and perceived behavioural control related to fruit and vegetable consumption. Attitudes, norms and perceived behavioural control significantly predicted changes in fruit and vegetable consumption.

Ethnicity and long-term heart rate variability in children

Background Low heart rate variability (HRV) is associated with increased cardiovascular disease risk. South Asians are at increased risk of cardiovascular disease. Methods This cross-sectional, observational study compared long-term HRV between South Asian and White European (EU) children. 155 children (92 White EU, 63 South Asian) aged 8±1 years wore a combined heart rate and activity monitor for 7 days. From 24-h beat-to-beat heart rate recordings, long-term HRV was calculated as the SD of the average RR intervals in each 5 min period (SDANN). Physical activity, daily energy expenditure, percentage body fat and maximal oxygen consumption (VO2max) were calculated using published or commercial algorithms. Results SDANN was significantly lower during the 24-h period in South Asian compared with White EU children (113±27 vs 130±28 ms, p<0.01, mean±SD) and during sleep (44±12 vs 54±16 ms, p<0.01, mean±SD). Ethnic differences in HRV were associated with lower levels of physical activity, daily energy expenditure, VO2max, and higher percentage body fat and resting heart rate, in South Asian children. Ethnic differences in HRV persisted despite statistical adjustment for these factors. SDANN was significantly lower in girls, but sex differences were no longer apparent when VO2max, physical activity and energy expenditure were statistically controlled for. Conclusions Our data confirm that South Asian children have lower HRV and reveal the novel information that the reduction is partially independent of physical activity and aerobic fitness.

Physical activity patterns of ethnic children from low socio-economic environments within the UK

Abstract Many children fail to meet physical activity (PA) guidelines for health benefits. PA behaviours are complex and depend on numerous interrelated factors. The study aims to develop current understanding of how children from low Socio-economic environments within the UK use their surrounding built environments for PA by using advanced technology. The environment was assessed in 96 school children (7–9 years) using global positioning system (GPS) monitoring (Garmin Forerunner, 305). In a subsample of 46 children, the environment and PA were assessed using an integrated GPS and heart rate monitor. The percentage of time spent indoor, outdoor, in green and non-green environments along with time spent in moderate-to-vigorous PA (MVPA) in indoor and outdoor environments were assessed. A 2-by-2 repeated measures analysis of covariance, controlling for body mass index, BF%, assessed the environmental differences. The findings show that 42% of children from deprived wards of Coventry fail to meet PA guidelines, of which 43% was accumulated during school. Children engaged in more MVPA outdoor than indoor environments (P < 0.01) and a greater amount of time was spent in non-green environments (P < 0.01). Increased time outdoors was negatively associated with BF%. In conclusion, outdoor environments are important for health-enhancing PA and reducing fatness in deprived and ethnic children.

Assessment of the ergogenic effect of caffeine supplementation on mood, anticipation timing, and muscular strength in older adults

The effect of caffeine to promote improvements in mood, cognition, and exercise performance has been well established in young and athletic adults. However, little is known about whether such nutritional ergogenic aids are effective in enhancing psychological well‐being, physiological or cognitive performance in older adults. This study assesses the ergogenic effect of caffeine on mood, perceptual‐motor coupling, and muscular strength in an older human population. Following a familiarization session, 12 apparently healthy volunteers (nine females and three males; 69 ± 6 years) completed two laboratory visits. “Pre ingestion” trials of mood state Brunel Mood State Inventory (BRUMS) and coincidence anticipation performance (Bassin anticipation timer) at slow (3 mph) and fast (8 mph) stimulus speeds were completed on both visits. Using a randomized, double‐blind, cross‐over design, participants consumed either caffeine (3 mg/kg body mass) or a placebo. Sixty minutes postingestion participants repeated the trials before completing a set of 10 consecutive repetitions of maximal knee extension using isokinetic dynamometry. Rating of perceived exertion (RPE) was assessed following the fifth and final repetition. Caffeine ingestion significantly improved mood state scores for vigor by 17% (P = 0.009) and reduced absolute error by 35% (P = 0.045) during coincidence anticipation assessment at 8 mph compared to placebo. There were no other significant effects. Caffeine ingestion failed to augment maximal voluntary contraction of the knee extensors and RPE did not prove to be significantly different to from placebo (P > 0.33 in each case). Acute caffeine ingestion may not be an effective ergogenic aid for improving muscular strength in older adults but could possibly be used as a nutrition supplement for enhancing mood and improving cognitive performance in daily living tasks where interceptive timing skills are required.

Environmental and school influences on physical activity in South Asian children from low socio-economic backgrounds: A qualitative study

South Asian (SA) children are less active but have enhanced metabolic risk factors. Physical activity (PA) is a modifiable risk factor for metabolic disease. Evidence suggests that environmental factors and socio-economic status influence PA behaviour. The purpose of this study was to understand PA environments, barriers and facilitators of PA in deprived environments for children from SA backgrounds. Focus groups were conducted with 5 groups of children aged 7–9 years (n = 33; male = 16, female = 17; SA = 17, White = 8 and Black = 8) from two schools in deprived wards of Coventry, England. Thematic analysis was used to identify key themes and subthemes across all transcripts. From the results, emergent themes included school and home environment, outdoor activity, equipment, weather, parental constraints and safety. Ethnic differences were apparent for sources of beliefs and knowledge and religious practice as constraints for PA. The findings suggest that school provides a good foundation for PA attitude, knowledge and behaviour, especially for SA children. To increase PA, multi-component interventions are needed, which focus on changing the home environment (i.e. junk food and media time), encouraging outdoors activity, changing perceptions of safety and weather conditions, which provide parental constraints for children. Interventions also need to be considerate to religious practices that might constrain time.