The human gastrointestinal tract (GIT) is inhabited by a wide cluster of microorganisms that play protective, structural, and metabolic functions for the intestinal mucosa. Gut microbiota is involved in the barrier functions and in the maintenance of its homeostasis. It provides nutrients, participates in the signaling network, regulates the epithelial development, and affects the immune system. Considering the microbiota ability to respond to homeostatic and physiological changes, some researchers proposed that it can be seen as an endocrine organ. Evidence suggests that different factors can determine changes in the gut microbiota. These changes can be both quantitative and qualitative resulting in variations of the composition and metabolic activity of the gut microbiota which, in turn, can affect health and different disease processes. Recent studies suggest that exercise can enhance the number of beneficial microbial species, enrich the microflora diversity, and improve the development of commensal bacteria. All these effects are beneficial for the host, improving its health status. In this paper, we intend to shed some light over the recent knowledge of the role played by exercise as an environmental factor in determining changes in microbial composition and how these effects could provide benefits to health and disease prevention.

The orexin-A/hypocretin-1 and orexin-B/hypocretin-2 are neuropeptides synthesized by a cluster of neurons in the lateral hypothalamus and perifornical area. Orexin neurons receive a variety of signals related to environmental, physiological and emotional stimuli, and project broadly to the entire CNS. Orexin neurons are “multi-tasking” neurons regulating a set of vital body functions, including sleep/wake states, feeding behaviour, energy homeostasis, reward systems, cognition and mood. Furthermore, a dysfunction of orexinergic system may underlie different pathological conditions. The selective loss orexin neurons was found in narcolepsia, supporting the crucial role of orexins in maintaining wakefulness. In animal models, orexin deficiency lead to obesity even if the consume of calories is lower than wildtype counterpart. Reduced physical activity appears the main cause of weight gain in these models resulting in energy imbalance. Interestingly, orexinergic neurons show connections to regions involved in cognition and mood regulation, including hippocampus. Orexins enhance hippocampal neurogenesis and improve spatial learning and memory abilities, and mood. Conversely, orexin deficiency results in learning and memory deficits, and depression.

In the present article we provide a review of current knowledge regarding the role played by physical activity (PA) in preventing age-related cognitive decline and reducing risk of dementia. The cognitive benefits of PA are highlighted by epidemiological, neuroimaging and behavioral studies. Epidemiological studies identified PA as a influential lifestyle factor in predicting rates of cognitive decline. Individuals physically active from midlife show a reduced later risk of cognitive impairment. Neuroimaging studies documented attenuation of age-related brain atrophy, and also increase of grey matter and white matter of brain areas, including frontal and temporal lobes. These structural changes are often associated with improved cognitive performance. Importantly, the brain regions that benefit from PA are also those regions that often are reported to be severely affected in dementia. Animal model studies provided significant information about biomechanisms that support exercise-enhanced neuroplasticity, such as angiogenesis and upregulation of growth factors. Among the growth factors, the BDNF seems to play an significant role. Another putative factor that might contribute to beneficial effects of exercise is the neuropeptide orexin-A. The beneficial effects of PA may represent an important resource to hinder the cognitive decline associated with aging.

The basal forebrain cholinergic system is considered as a major component of attentive mediator system. It could be activated by different ingoing inputs, and among them the hypothalamus represents an important source of projections and the orexin neurons, whose cell bodies are present in the lateral hypothalamus, highly contribute to these projections. Recently, the orexin-producing neurons have been considered to act in the basal forebrain promoting arousal and attention. Aim of the present review is trying to explain the putative effects of orexin-producing neurons and their projection to the basal forebrain in order to support the hypothesis that orexin system may contribute to attentional processing toward increased cell activity and cortical acetylcholine (Ach) release. Collectively, the available data seem to support this hypothesis: orexins excite cholinergic neurons increasing acetylcholine release in cerebral cortex contributing to cerebral cortical activation and prefrontal cortex associated with executive system. We have reviewed evidence suggesting that the BF may be a key target through which orexin neurons promote attention.

Structural and functional changes of the brain occur throughout life to cope with new demands. This review examines the main findings obtained from two significant lines of research. The first line of research encompasses the studies showing the beneficial effects of the physical exercise on hippocampal neurogenesis and cognition. The enhancement of the cognitive abilities produced by exercise represents a valuable and promising tool for preventing cognitive decline associated with aging. The second line of research refers to the study of the hypocretin-1/orexin-A influence on hippocampus functioning. Recent research suggests that hypocretin-1/orexin-A increases during exercise and it plays a significant role at the level of the hippocampus in regulating social cognition and mood.

The prevalence of obesity has become a global health concern, with significant impacts on quality of life and mortality rates. Recent research has highlighted the role of ultra-processed foods (UPFs) in driving the obesity epidemic. UPFs undergo extensive processing, often containing high levels of sugars, fats, and additives, while lacking essential nutrients. Studies have linked UPF consumption to obesity and cardiometabolic diseases, underscoring the importance of dietary patterns rich in whole foods. Thus, the aim of this narrative review is to elucidate the correlation between ultra-processed foods and the increased trend of obesity and its related complications. These foods, prevalent in modern diets, contribute to nutritional deficiencies and excessive caloric intake, exacerbating obesity rates. Lifestyle factors such as busy schedules and quick meal management further drive UPF consumption, disrupting hunger regulation and promoting overeating. UPF consumption correlates with adverse health outcomes, including dyslipidemia, hypertension, and insulin resistance. Promoting whole, minimally processed foods and implementing school-based nutrition education programs are crucial steps. Also, numerous challenges exist, including unequal access to healthy foods, the industry’s influence, and behavioral barriers to dietary change. Future research should explore innovative approaches, such as nutrigenomics and digital health technologies, to personalize interventions and evaluate policy effectiveness. Collaboration across disciplines and sectors will be vital to develop comprehensive solutions and improve public health outcomes globally.