The relations between objectively measured moderate-to-vigorous physical activity, chronic aerobic exercise and cognitive control in children and adolescents

Physical inactivity among young people is a public health concern. Markers of physical inactivity, such as low cardio-respiratory fitness (CRF) and obesity are adversely related to higher order cognitive functions, which underpin goal directed behaviour (i.e. cognitive control) and are implicated in academic achievement. Regular aerobic exercise can benefit cognitive control in children. However, it remains unknown whether daily physical activity behaviour is associated with cognitive control. Investigating this is important as targeting increments in daily moderate-to-vigorous physical activity (MVPA) may initially be a more realistic policy goal than developing aerobic exercise interventions. Nominal number of studies assessed this relationship using objective monitoring of physical activity (accelerometry), and yielded mixed results. None of the studies into objectively measured physical activity and cognitive function in young people controlled for CRF, which is posited to mediate the relationship between regular aerobic exercise and cognitive control. Likewise, other important confounders such as intelligence, have yet to be addressed in the literature. Moreover, it is unknown whether this relationship varies with age, as extant studies looked solely at younger adolescents. For example, meta-analytical findings (Fedewa & Ahn, 2011) suggest that children can benefit more cognitively from CRF and chronic aerobic exercise than adolescents as greater effect sizes have been observed for younger compared to older youngsters. Alternatively, chronic aerobic exercise may be specifically needed for cognitive benefits to emerge. However, none of the aerobic exercise interventions included objective assessments of baseline physical activity and few studies assessed the effects of chronic aerobic exercise interventions on multiple indices of cognitive control. This thesis aimed to address the limitations of previous research and to investigate: 1) the associations between objectively measured daily MVPA and cognitive control in older adolescents (study 1), and 2) in preadolescent children (study 2), while controlling for CRF, general intellectual ability and a number of important confounders (e.g. adiposity, attention-deficit hyperactivity disorder); 3) the relationship between daily MVPA and academic achievement (study 2); 4) the effects of chronic aerobic exercise intervention on cognitive control in children, while controlling for objectively measured daily MVPA and time sedentary at baseline (study 3). Methods: Study 1. A sample of 667 adolescents (Mage = 15.4, SD = .17, 55.5% girls) from the Avon Longitudinal Study of Parents and Children was included in the analyses. MVPA was measured with ActiGraph, GT1M accelerometer. CRF was assessed with sub-maximal cycle ergometer test and expressed as weight adjusted predicted physical work capacity at the heart rate of 170 beats per minute (PWC-170). Attentional control was measured with Stop Signal task. Study 2. A sample of 81 children (Mage = 8.64 years, SD = .57, 45.7 % girls) was included in the analyses. MVPA was objectively measured using the ActiGraph, wGT3X+ accelerometer. CRF was measured using a maximal graded exercise test on a treadmill. Inhibitory control was assessed with a modified Eriksen flanker task, working memory with Operation Span Task; and academic achievement with Kaufman Test of Educational Achievement. Study 3. 32 children (Mage = 8.64, SD = .58, 56.2% girls) were randomised into a physical activity intervention (FITKids2) or a waitlist control group. Changes in VO2max were measured using a maximal graded treadmill exercise test and changes in MVPA were objectively monitored for 7 days using the ActiGraph, wGT3X+ accelerometer. Behavioural measures of inhibition (reaction time, and accuracy) and working memory (accuracy) were taken using computerised laboratory tasks (modified Eriksen flanker task and Operation Span Task). Results: Study 1. MVPA was not significantly related to cognitive processing speed or variability of cognitive performance in hierarchical linear regression models. In simple regression models, CRF was negatively related to mean RT on the simple go condition (R2 = 2.6%, F(1, 308) = 8.28, p = .004). Study 2. No significant associations were noted between MVPA and either inhibition, working memory, or academic achievement. In contrast, CRF explained 4.7% of variance in accuracy interference (∆R2 = .047, p = .045; β = -.22, t(78) = 2.03, p = .045, F(2, 78) = 4.95, p = .009). Study 3. FITKids2 physical activity intervention had a positive effect on the speed of responding during incongruent condition of flanker task (F(1, 30) = 4.69, p = .038, ƞp2 = .13). A significant increase in BMI percentile was observed in the control (Z = 2.17, p = .03) but not in the intervention group (p = .53). Discussion: Study 1. Our results suggest that aerobic fitness, but not MVPA, was associated with cognitive processing speed under less cognitively demanding task conditions. The results thus indicate a potential global effect of aerobic fitness on cognitive functions in adolescents but this may differ depending on the specific task characteristics. Study 2. The results of this study suggest that CRF but not objectively measured MVPA was associated with better interference control in preadolescent children. Given the intermittent nature of children s daily MVPA, it is possible that aerobic exercise, which increases CRF is needed for cognitive benefits to emerge. Study 3. FITKids2 after-school physical activity intervention had a positive effect on children s inhibitory control, namely this cognitive function, which is closely related to academic achievement and future job and health outcomes. Thus, the results of this study convey a positive public health message, where promoting child s engagement in aerobic exercise can engender benefits to their cognitive function. Conclusions: The findings from this thesis can inform development of physical activity interventions to benefit cognitive functions in young people and contribute to the evidence base to inform future health and educational policies

Probiotics and Its Relationship with the Cardiovascular System

Cardiovascular disease is a major health issue worldwide. Individuals who have cardiovascular disease, are often at risk or already have other diseases, which together can lead to metabolic syndromes and possibly increase the risk of morbidity and mortality. Gut microbial balance is increasingly being recognized as a possible risk factor in cardiovascular illnesses. Studies published so far have shown a possible link to hypertension, hyperlipidemia and associated cardiac illnesses. Balance of the colonic flora seems to improve these co-morbid conditions. Probiotics have been studied in several studies to determine if their use provides a beneficial non-pharmacological treatment option for diseases such as diabetes, obesity, hypercholesterolemia, hypertension, chronic kidney disease, cardiomyopathy and atherosclerosis. Placebo, double blinded controlled studies are s needed to determine if these perceived beneficial effects exists and to what extent probiotics play in the overall outcome in cardiovascular diseases

High-intensity intermittent exercise: effect on young people’s cardiometabolic health and cognition

With only a quarter of young people currently meeting physical activity guidelines, two key areas of concern are the effects of exercise on cardio-metabolic health and cognition. Despite the fact that physical activity in young people is typically high intensity and intermittent in nature; much of the literature examines traditional endurance type exercise. This review provides an update on the effects of high intensity intermittent exercise on young people’s cardio-metabolic health and cognition. High intensity intermittent exercise has acute beneficial effects on endothelial function and postprandial lipemia and chronic positive effects on weight management. In addition, there is emerging evidence regarding chronic benefits on blood lipid profile, blood pressure and pro- and anti-inflammatory cytokines. Furthermore, emerging evidence suggests beneficial acute and chronic effects of high intensity intermittent exercise on cognition. However, further research is required in both cardio-metabolic health and cognition, particularly regarding the impact of school-based interventions in adolescents

Dietary fibre as a unifying remedy for the whole spectrum of obesity-associated cardiovascular risk

Obesity is a pandemic carrying the heavy burden of multiple and serious co-morbidities including metabolic syndrome, type 2 diabetes and cardiovascular diseases. The pathophysiological processes leading to the accumulation of body fat slowly evolve to fat accumulation in other body compartments than subcutaneous tissue. This abnormal fat deposition determines insulin resistance which in turn causes blood glucose and lipid metabolism derangement, non-alcoholic fatty liver disease, hypertension, and metabolic syndrome. All these conditions contribute to increase the cardiovascular risk of obese people. Several randomized clinical trials demonstrated that moderate weight loss (5–10%) in obese patients improves obesity-related metabolic risk factors and coexisting disorders. Therefore, nutritional strategies able to facilitate weight management, and in the meantime positively influence obesity-associated cardiovascular risk factors, should be implemented. To this aim, a suitable option could be dietary fibres that may also act independently of weight loss. The present narrative review summarizes the current evidence about the effects of dietary fibres on weight management in obese people. Moreover, all of the different cardiovascular risk factors are individually considered and evidence on cardiovascular outcomes is summarized. We also describe the plausible mechanisms by which different dietary fibres could modulate cardio-metabolic risk factors. Overall, despite both epidemiological and intervention studies on weight loss that show statistically significant but negligible clinical effects, dietary fibres seem to have a beneficial impact on main pathophysiological pathways involved in cardiovascular risk (i.e., insulin resistance, renin-angiotensin, and sympathetic nervous systems). Although the evidence is not conclusive, this suggests that fibre would be a suitable option to counteract obesity-related cardio-metabolic diseases also independently of weight loss. However, evidence is not consistent for the different risk factors, with clear beneficial effects shown on blood glucose metabolism and Low Density Lipoprotein (LDL) cholesterol while there is fewer, and less consistent data shown on plasma triglyceride and blood pressure. Ascribing the beneficial effect of some foods (i.e., fruits and vegetables) solely to their fibre content requires more investigation on the pathophysiological role of other dietary components, such as polyphenols

Using polyphenols as a relevant therapy to diabetes and its complications, a review

Diabetes is currently a worldwide health concern. Hyperglycemia, hypertension, obesity, and oxi dative stress are the major risk factors that inevitably lead to all the complications from diabetes. These complications severely impact the quality of life of patients, and they can be managed, reduced, or even reverted by several polyphenols, plant extracts and foods rich in these com pounds. The goal of this review is to approach diabetes not as a single condition but rather an interconnected combination of risk factors and complications. This work shows that polyphenols have multi target action and effects and they have been systematically proven to be relevant in the reduction of each risk factor and improvement of associated complication.info:eu-repo/semantics/publishedVersio

Epigallocatechin-3-Gallate Reduces Fat Accumulation in Caenorhabditis Elegans

Epigallocatechin gallate (EGCG), also known as epigallocatechin-3-gallate, is a polyphenol that is most abundant in tea. It has been shown from many studies that consumption of EGCG can contribute to weight loss, however, the underlying mechanism is not fully understood. To determine how EGCG acts to reduce fat, an organism model Caenorhabditis elegans (C. elegans) is introduced, which is a useful animal system in exploring crucial biological mechanisms that are readily applicable to humans. In this study, different strains were raised for two days on a diet with or without 100µM and 200µM EGCG treatment: N2 (i.e., wild type) and mutants (i.e., knockdown of fat metabolism related genes). EGCG’s effect on fat reduction was characterized by triglyceride content, food consumption and physiological behaviors. Our results showed that 100 and 200 µM EGCG significantly reduced the triglyceride content of wild type worms by 10% and 20%, respectively, without affecting its food intake and physiological behaviors. Additionally, EGCG could effectively reduce fat accumulation in C. elegans dependent on acs-2 and atgl-1

Diet-Derived Antioxidants and Their Role in Inflammation, Obesity and Gut Microbiota Modulation

It is generally accepted that gut microbiota, inflammation and obesity are linked to the development of cardiovascular diseases and other chronic/non-communicable pathological conditions, including cancer, neurodegenerative diseases and ageing-related disorders. In this scenario, oxidative stress plays a pivotal role. Evidence suggests that the global dietary patterns may represent a tool in counteracting oxidative stress, thus preventing the onset of diseases related to oxidative stress. More specifically, dietary patterns based on the regular consumption of fruits and vegetables (i.e., Mediterranean diet) have been licensed by various national nutritional guidelines in many countries for their health-promoting effects. Such patterns, indeed, result in being rich in specific components, such as fiber, minerals, vitamins and antioxidants, whose beneficial effects on human health have been widely reported. This suggests a potential nutraceutical power of specific dietary components. In this manuscript, we summarize the most relevant evidence reporting the impact of dietary antioxidants on gut microbiota composition, inflammation and obesity, and we underline that antioxidants are implicated in a complex interplay between gut microbiota, inflammation and obesity, thus suggesting their possible role in the development and modulation of chronic diseases related to oxidative stress and in the maintenance of wellness. Do all roads lead to Rome

Advantages of bariatric medicine for individualized prevention and treatments: multidisciplinary approach in body culture and prevention of obesity and diabetes

Bariatric surgery is a component of the multimodal treatment of obesity, which consists of multidisciplinary evaluation and diagnosis, conservative and surgical treatments, and lifelong follow-up care. The current guideline extends the BMI-based spectrum of indications that was previously proposed (BMI greater than 40 kg/m(2), or greater than 35 kg/m(2) with secondary diseases) by eliminating age limits, as well as most of the contraindications. A prerequisite for surgery is that a structured, conservative weight-loss program has failed or is considered to be futile. Type 2 diabetes is now considered an independent indication under clinical study conditions for patients whose BMI is less than 35 kg/m(2) (metabolic surgery). The standard laparoscopic techniques are gastric banding, gastric bypass, sleeve gastrectomy, and biliopancreatic diversion. The choice of procedures is based on knowledge of the results, long-term effects, complications, and individual circumstances. Structured lifelong follow-up should be provided and should, in particular, prevent metabolic deficiencies