Background Gut microbiota is considered to have a great impact on human health and disease. While it is widely recognized that the gut microbiota of healthy individuals differs from those with obesity, inflammatory bowel disease, metabolic syndrome, and other chronic diseases, the alterations of gut microbiota with physical activity are not fully understood. Accordingly, we performed this systematic review to address the question regarding the effects of mild and intense exercise on the gut microbiota in humans. Methods The comparative analyses of gut microbiota were conducted following the PRISMA protocol to determine the differences in the active vs. non-active individuals (phenotypes) (n = 11), including the influence of physical activity intervention on the human gut microbiota (n = 13); the differences in the gut microbiota of athletes vs. non-athletes (n = 8); and the microbiota status at different stages of athletic performance or intervention (n = 7), with various of physical activities, sport disciplines, and activity duration. Literature searches were completed using four databases: PubMed, Web of Science, Scopus, and EBSCO, and 2090 articles were retrieved by using appropriate keywords. The low heterogeneity of the studies hasn’t allowed us to prepare a meta-analysis. After excluding 2052 articles, we ultimately selected 38 articles that met the eligibility criteria for this review. Results The data analyses revealed that in non-athletes rising physical activity markedly influenced the relative abundance of short-chain fatty acid (SCFA). Aerobic training that lasted 60 min, and physical activity that characterized 60% HRmax or more also influenced beta diversity indexes. The results showed that athletes harbor a more diverse type of intestinal microflora than non-athletes, but with a relatively reduced abundance of SCFA- and lactic acid-producing bacteria, thereby suggesting an adverse effect of intense exercise on the population of gut microbiota. Conclusion It is concluded that the level of physical activity modulates the gastrointestinal microbiota in humans. For a long period, increasing the intensity and volume of exercise may lead to gut dysbiosis. Perhaps, proper supplementation should be considered to keep gut microbiota in large biodiversity and richness, especially under unfavorable gut conditions associated with intense exercise. Trial registration Prospero CRD42021264064.

The aim of this study was to compare the levels of the plasma muscle-derived cytokines (myokines) and reactive oxygen and nitrogen species (RONS) after muscle damage triggered by different exercises, and to demonstrate the relationships between RONS, thiol redox status and myokines. Sixteen young men participated in a 90-min run at 65 % VO2max (Ex.1) or 90-min run at 65 % VO2max finished with a 15-min eccentric phase (Ex.2, downhill running). Plasma samples were collected before and at 20 min, 24 h and 48 h after exercise. The exercise trials significantly elevated the concentrations of plasma hydrogen peroxide (H2O2) and 8-isoprostane at 20 min rest. Myokines IL-6 and IL-10 increased at 20 min rest while IL-1β and TNFα increased at 24 h rest following both running. Ex.2 caused a significant increase in nitric oxide (NO), IL-6, IL-10 and oxidized glutathione (GSSG) levels. Thiol redox status (GSHtotal2GSSG/GSSG) decreased by about 30 % after Ex.2 as compared to Ex.1. H2O2 and NO directly correlated with IL-6, IL-10, IL-1β, TNFα and glutathione. These results show that eccentric work is an important factor that enhances the production of RONS and muscle-derived cytokines, and that there is a possible participation of thiol redox status in the release of myokines to blood.

An intensive physical exercise program could lead to a decrease in immune system function. Effects of long-term supplementation of bovine colostrum on the response of immune function on physical exercise test in athletes were examined. Twenty-seven elite female basketball players (age 16–19) were randomly assigned to either an experimental group or a control group. Eventually, n = 11 athletes completed intervention in the experimental group (3.2 g bovine colostrum orally twice a day for 24 weeks), while n = 9 athletes in the control group were given a placebo. Before the supplementation, after 3 and 6 months, subjects performed the physical exercise stress test. Before, just after, and 3 h after physical exercise testing, blood was drawn and immune system indicators were examined. Plasma interleukin (IL)-1alpha, IL-2, IL-10, IL-13, tumor necrosis factor (TNF) alpha, creatine kinase (CK MM), immunoglobulin G (IgG), insulin-like growth factor 1 (IGF1), and WBC, lymphocyte (LYM), monocyte (MON), and granulocyte (GRA) were measured. A statistically significant change in IL-10 in response to the exercise program during the supplementation period in both groups was observed (p = 0.01). However, the results of the rest of the comparisons were statistically insignificant (p > 0.05). Contrary to our initial hypothesis, there were no significant effects of bovine supplementation on the dynamics of immune system function indicators.

Background: Bovine colostrum (BC) contains a myriad of bioactive molecules that are renowned for possessing unique medicinal benefits in children and adults, and BC supplements are considered safe and cost-effective options to manage/prevent the incidence of upper respiratory tract infections and gut-related problems in athletes. In this review, we will try to answer the question: How will BC supplementation ameliorate gut permeability problems among athletes? Methods: Literature searches were performed using PRISMA guidance to identify studies assessing the influence of BC supplements on gut permeability. Studies were selected using four databases: PubMed, Web of Science, Scopus, and EBSCO, and a total number of 60 articles were retrieved by using appropriate keywords. Results: Nine studies were selected that met the eligibility criteria for this review. The data analysis revealed that vigorous exercise profoundly increases intestinal permeability, and BC supplementation helps to reverse gut permeability in athletes. Conclusion: BC supplementation may be highly beneficial in improving gut permeability in athletes. However, well-designed, placebo-controlled, and randomized studies are needed to evaluate the long-term safety and efficacy and to determine the optimal dose schedules of BC supplementation in high-performance athletes.

α-Lipoic acid (αLA), as an inductor of hydrogen peroxide (H2O2) and nitrogen oxide (NO) generation and modulator of thiol redox status, plays an important role in cell signalling pathways. The study was designed to observe the effect of αLA on inflammatory response through changes in H2O2 and NO levels as well as thiol redox status. Sixteen physically active males were randomly assigned to one of two groups: placebo or αLA (1,200 mg d(-1) for 10 days prior to exercise). The exercise trial involved a 90-min run at 65% VO2max (0% gradient) followed by 15-min eccentric phase at 65% VO2max (-10% gradient). Blood samples were collected before the exercise trial and then again 20 min, 24, and 48 h after. αLA significantly elevated H2O2 but reduced NO generation before or after exercise. Thiol redox status (GSHtotal-2GSSG/GSSG) increased by >50% after αLA and exercise (ANOVA, P < 0.05) and correlated with changes in cytokines interleukin-6 (IL-6) (r = -0.478, P < 0.05) and IL-10 (r = -0.455, P < 0.05). This was caused by strong effect of αLA on GSSG concentration. αLA elevated IL-6 and IL-10 levels at 20 min after exercise and decreased in interleukin-1β and tumor necrosis factor α before and after exercise. This enhanced the regeneration of injured muscles. Creatine kinase activity tended to lower values after αLA intake. The study suggests that the combination of intense exercise with α-lipoic acid intake might be useful to improve the skeletal muscle regeneration through changes in inflammatory response which are associated with H2O2 and NO generation as well as thiol redox status.