How much exercise should be promoted to raise total daily energy expenditure and improve health?

Frequency-Response Relationship Between Exercise and Locomotive Syndrome Across Age Groups: Secondary Analysis of a Nationwide Cross-Sectional Study in Japan

OBJECTIVES

This study aimed to clarify the frequency-response relationship between exercise habits and locomotive syndrome in different age groups.

METHODS

We analyzed 8,681 independent community dwellers who participated in a nationwide cross-sectional locomotive syndrome study. Participants were divided into young (20-39 years), middle (40-64 years), and old (≥ 65 years) groups. The presence of locomotive syndrome was evaluated using the locomotive syndrome risk tests. Exercise habits were assessed by exercise frequency (almost every day/sometimes/occasionally/never). The association between locomotive syndrome and exercise was assessed using the multiple logistic regression analysis adjusted for participant characteristics for each age category.

RESULTS

Overall, 3,528 (41%) participants had locomotive syndrome. In the old group, the risk of locomotive syndrome was lower with an increased exercise frequency. However, this dose-response relationship was not found in the young group. The proportion of locomotive syndrome was lower even in participants who occasionally exercised (1-3 days/month) than those who never exercise in the young and middle age groups.

CONCLUSIONS

Regular exercise reduced the risk of locomotive syndrome not only in middle and older adults but also in young adults. Moreover, increasing exercise frequency may provide benefits for locomotive syndrome prevention, especially among older adults.

Effects of Ketogenic Diet on Some Immunological Parameters

&lt;b&gt;Background and Objective:&lt;/b&gt; A well-established treatment for childhood epilepsy, the Ketogenic Diet (KD) is increasingly gaining acceptance as a preventative tool for obesity. The current study aims to compare the effects of a ketogenic diet on some of the immunological parameters among obese individuals and contrast them with non-obese individuals. This includes finding the absolute numbers of white blood cells and estimating the efficacy of phagocytic cells and serum IgA concentration. &lt;b&gt;Materials and Methods:&lt;/b&gt; Twenty healthy persons were chosen for the study, with an age range between 18-45 years, a weight range before the ketogenic diet of 80-115 kg and after the ketogenic diet 60-80 kg with a height range between 155-180 cm during a period between 8-16 weeks. Their daily food was composed of high fats (80%), moderate protein (15%) and small amounts of carbohydrates (<5%). The control sample included twenty healthy subjects, their food consisted of different types of food carbohydrates (75-80%), proteins (10%) and fats (<10%). &lt;b&gt;Results:&lt;/b&gt; The results showed a significant increase in the White Blood Cells (WBC) count in KD individuals. Additionally, no significant difference was noticed in the absolute number of neutrophils and lymphocytes. Conversely, a significant increase in the absolute number of monocytes was observed. Moreover, the study showed a significant decrease in IgA concentration in KD individuals compared with control. &lt;b&gt;Conclusion:&lt;/b&gt; In the ketogenic system users indicated a rise in the number of monocytes and a decrease in the concentration of IgA. This provides a strong sign that autoimmune disorders are emerging.

Low-intensity exercise stimulates bioenergetics and increases fat oxidation in mitochondria of blood mononuclear cells from sedentary adults

AIM

Exercise training induces adaptations in muscle and other tissue mitochondrial metabolism, dynamics, and oxidative phosphorylation capacity. Mitochondrial fatty acid oxidation was shown to be pivotal for the anti-inflammatory status of immune cells. We hypothesize that exercise training can exert effects influence mitochondrial fatty acid metabolism in peripheral blood mononuclear cells (PBMCs). The aim was to investigate the effect of exercise on the fatty acid oxidation-dependent respiration in PBMCs.

DESIGN

Twelve fasted or fed volunteers first performed incremental-load exercise tests to exhaustion on a cycle ergometer to determine the optimal workload ensuring maximal health benefits in volunteers with a sedentary lifestyle. In addition, the same volunteers performed 60 min of low-intensity constant-load exercise.

RESULTS

In the incremental-load exercise, the maximal whole-body fat oxidation rate measured by indirect calorimetry was reached at the fasted state already at a 50 W workload. At the 75-175 W workloads, the contribution of fat oxidation significantly decreased to only 11%, the heart rate increased to 185 BPM, and the study participants reached exhaustion. These results show that low-intensity exercise (50W) is optimal for maximal whole-body fat utilization. After low-intensity exercise, the ROUTINE mitochondrial respiration, as well as fatty acid oxidation-dependent respiration in PBMCs at LEAK and OXPHOS states, were significantly increased by 31%, 65%, and 76%, respectively. In addition, during 60 min of low-intensity (50W) exercise, a 2-fold higher lipolysis rate was observed and 13.5 ± 0.9 g of fat was metabolized, which was 57% more than the amount of fat that was metabolized during the incremental-load exercise.

CONCLUSIONS

In individuals with a sedentary lifestyle participating in a bicycle ergometry exercise program, maximal lipolysis and whole-body fat oxidation rate is reached in a fasted state during low-intensity exercise. For the first time, it was demonstrated that low-intensity exercise improves bioenergetics and increases fatty acid oxidation in PBMCs and may contribute to the anti-inflammatory phenotype.

Social norms and obesity prevalence: From cohort to system dynamics models

Group-level obesity can be seen as an emergent property of a complex system, consisting of feedback loops between individual body weight perception, individual weight-related behaviour and group-level social norms (a product of group-level 'normal' body mass index (BMI) and sociocultural 'ideal' BMI). As overweight becomes normal, the norm might be counteracting health awareness in shaping individual weight-related behaviour. System dynamics modelling facilitates understanding and simulating this system's emergent behaviour. We constructed six system dynamics models (SDMs) based on an expert-informed causal loop diagram and data from six sociocultural groups (Dutch, Moroccan and South-Asian Surinamese men and women). The SDMs served to explore the effect of three scenarios on group-level BMI: 'what if' weight-related behaviour were driven by (1) health awareness, (2) norms or (3) a combination of the two. Median BMI decreased approximately 50% and 30% less in scenarios 2 and 3, respectively, than in 1. In men, the drop in BMI was approximately two times larger in scenario 1 versus 3, whereas in women, the drop was approximately equal in these scenarios. This study indicates that the overweight norm in men holds group-level BMI close to overweight despite health awareness. Since norms are counteracting health awareness less strongly in women, other drivers of obesity must be more relevant.

Precision medicine and healthy living: The importance of the built environment

The built environment encompasses the major physical spaces, including buildings, streets, homes, schools, parks, playgrounds and other infrastructure in which we live, work and play. In an ideal world, the built environment should support and facilitate a healthy engagement in physical activity across the lifespan. However, in the context of an environment characterized by increased mechanization and urbanization, physical inactivity and higher levels of overweight and obesity, too many settings are not conducive to physical activity and/or are not safe and walkable. In the knowledge that there are multiple challenges to redress the low levels of physical activity seen in many parts of the world, this paper provides some examples of opportunities for healthy living (HL) in a built environment characteristic of an increasingly urbanized world. Particular foci include opportunities for HL fostered in child-friendly cities, in which walkability is high, and active transport is encouraged and supported.

Targeting lifestyle energy expenditure in the management of obesity and health: from biology to built environment

Increasing lifestyle energy expenditure has long been advocated in the prevention and treatment of obesity, as embodied in the ancient prescription of Hippocrates (the 'father of modern medicine') that people with obesity should eat less and exercise more. However, the long-term outcome of exercise alone or in combination with dieting in obesity management is poor. To understand the reasons underlying these failures and to develop novel strategies that target lifestyle energy expenditure in both prevention and treatment of obesity, research over the past decades has focused on (i) the interactions between physical activity and body weight (and its composition) throughout the lifespan; (ii) the influence of biology and potential compensatory changes in energy expenditure, food intake and food assimilation in response to energy deficits; and (iii) the impact of the built environment (outdoor and indoor) and smart technology on physical activity behaviours, thermoregulatory thermogenesis and metabolic health. It is against this background that recent advances relevant to the theme of 'Targeting Lifestyle Energy Expenditure in the Management of Obesity and Health: From Biology to Built Environment' are addressed in this overview and the nine review articles in this supplement, reporting the proceedings of the 9th Fribourg Obesity Research Conference.