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Molecular Mechanisms Underlying the Beneficial Effects of Exercise on Brain Function and Neurological Disorders.
Nay, K, Smiles, WJ, Kaiser, J, McAloon, LM, Loh, K, Galic, S, Oakhill, JS, Gundlach, AL, Scott, JW
International journal of molecular sciences. 2021;22(8)
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Exercise as therapy for mental health disorders has become common due to its reported benefits and low cost. There are many biological ways in which exercise may help mood disorders and diseases associated with brain degeneration and this review article aimed to highlight these. The authors first highlighted the research indicating that exercise may be protective in mood disorders with studies showing reduction of symptoms of depression, anxiety, schizophrenia, autism, and bipolar disorder. Exercise may also be of benefit in several brain degenerative disorders with studies indicating a positive impact in individuals with Parkinson’s disease, Alzheimer’s disease, Huntington’s disease, and Multiple Sclerosis. Studies have also indicated that individuals with brain injuries, such as stroke may also benefit. Several reasons for this were highlighted. When muscle is stimulated during exercise a key brain signalling molecule may be produced, known as brain-derived neurotrophic factor (BDNF). BDNF may have the effect of preventing brain degeneration and promoting regeneration. Exercise may also increase gut microbial diversity and increase beneficial bacteria which may benefit the brain in several ways. It was concluded that exercise may have beneficial effects for individuals with brain disorders. This study could be used by healthcare professionals to understand how exercise may be of benefit to individuals with mood disorders, brain degenerative diseases and brain injuries as part of a holistic treatment plan.
Abstract
As life expectancy has increased, particularly in developed countries, due to medical advances and increased prosperity, age-related neurological diseases and mental health disorders have become more prevalent health issues, reducing the well-being and quality of life of sufferers and their families. In recent decades, due to reduced work-related levels of physical activity, and key research insights, prescribing adequate exercise has become an innovative strategy to prevent or delay the onset of these pathologies and has been demonstrated to have therapeutic benefits when used as a sole or combination treatment. Recent evidence suggests that the beneficial effects of exercise on the brain are related to several underlying mechanisms related to muscle-brain, liver-brain and gut-brain crosstalk. Therefore, this review aims to summarize the most relevant current knowledge of the impact of exercise on mood disorders and neurodegenerative diseases, and to highlight the established and potential underlying mechanisms involved in exercise-brain communication and their benefits for physiology and brain function.
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Does Physical Inactivity Induce Significant Changes in Human Gut Microbiota? New Answers Using the Dry Immersion Hypoactivity Model.
Jollet, M, Nay, K, Chopard, A, Bareille, MP, Beck, A, Ollendorff, V, Vernus, B, Bonnieu, A, Mariadassou, M, Rué, O, et al
Nutrients. 2021;(11)
Abstract
Gut microbiota, a major contributor to human health, is influenced by physical activity and diet, and displays a functional cross-talk with skeletal muscle. Conversely, few data are available on the impact of hypoactivity, although sedentary lifestyles are widespread and associated with negative health and socio-economic impacts. The study aim was to determine the effect of Dry Immersion (DI), a severe hypoactivity model, on the human gut microbiota composition. Stool samples were collected from 14 healthy men before and after 5 days of DI to determine the gut microbiota taxonomic profiles by 16S metagenomic sequencing in strictly controlled dietary conditions. The α and β diversities indices were unchanged. However, the operational taxonomic units associated with the Clostridiales order and the Lachnospiraceae family, belonging to the Firmicutes phylum, were significantly increased after DI. Propionate, a short-chain fatty acid metabolized by skeletal muscle, was significantly reduced in post-DI stool samples. The finding that intestine bacteria are sensitive to hypoactivity raises questions about their impact and role in chronic sedentary lifestyles.
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Simulated microgravity disturbs iron metabolism and distribution in humans: Lessons from dry immersion, an innovative ground-based human model.
Nay, K, Koechlin-Ramonatxo, C, Rochdi, S, Island, ML, Orfila, L, Treffel, L, Bareille, MP, Beck, A, Gauquelin-Koch, G, Ropert, M, et al
FASEB journal : official publication of the Federation of American Societies for Experimental Biology. 2020;(11):14920-14929
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Abstract
The objective of the present study was to determine the effects of dry immersion, an innovative ground-based human model of simulated microgravity and extreme physical inactivity, on iron homeostasis and distribution. Twenty young healthy men were recruited and submitted to 5 days of dry immersion (DI). Fasting blood samples and MRI were performed before and after DI exposure to assess iron status, as well as hematological responses. DI increased spleen iron concentrations (SIC), whereas hepatic iron store (HIC) was not affected. Spleen iron sequestration could be due to the concomitant increase in serum hepcidin levels (P < .001). Increased serum unconjugated bilirubin, as well as the rise of serum myoglobin levels support that DI may promote hemolysis and myolysis. These phenomena could contribute to the concomitant increase of serum iron and transferrin saturation levels (P < .001). As HIC remained unchanged, increased serum hepcidin levels could be due both to higher transferrin saturation level, and to low-grade pro-inflammatory as suggested by the significant rise of serum ferritin and haptoglobin levels after DI (P = .003 and P = .003, respectively). These observations highlight the need for better assessment of iron metabolism in bedridden patients, and an optimization of the diet currently proposed to astronauts.