Exercise and the immune system: a model of the stress response?

Molecular insights of exercise therapy in disease prevention and treatment

Despite substantial evidence emphasizing the pleiotropic benefits of exercise for the prevention and treatment of various diseases, the underlying biological mechanisms have not been fully elucidated. Several exercise benefits have been attributed to signaling molecules that are released in response to exercise by different tissues such as skeletal muscle, cardiac muscle, adipose, and liver tissue. These signaling molecules, which are collectively termed exerkines, form a heterogenous group of bioactive substances, mediating inter-organ crosstalk as well as structural and functional tissue adaption. Numerous scientific endeavors have focused on identifying and characterizing new biological mediators with such properties. Additionally, some investigations have focused on the molecular targets of exerkines and the cellular signaling cascades that trigger adaption processes. A detailed understanding of the tissue-specific downstream effects of exerkines is crucial to harness the health-related benefits mediated by exercise and improve targeted exercise programs in health and disease. Herein, we review the current in vivo evidence on exerkine-induced signal transduction across multiple target tissues and highlight the preventive and therapeutic value of exerkine signaling in various diseases. By emphasizing different aspects of exerkine research, we provide a comprehensive overview of (i) the molecular underpinnings of exerkine secretion, (ii) the receptor-dependent and receptor-independent signaling cascades mediating tissue adaption, and (iii) the clinical implications of these mechanisms in disease prevention and treatment.

Non-coding RNAs in exercise immunology: A systematic review

Regular physical exercise has been recognized as a potent modulator of immune function, with its effects including enhanced immune surveillance, reduced inflammation, and improved overall health. While strong evidence exists that physical exercise affects the specific expression and activity of non-coding RNAs (ncRNAs) also involved in immune system regulation, heterogeneity in individual study designs and analyzed exercise protocols exists, and a condensed list of functional, exercise-dependent ncRNAs with known targets in the immune system is missing from the literature. A systematic review and qualitative analysis was used to identify and categorize ncRNAs participating in immune modulation by physical exercise. Two combined approaches were used: (a) a systematic literature search for "ncRNA and exercise immunology", (b) and a database search for microRNAs (miRNAs) (miRTarBase and DIANA-Tarbase v8) aligned with known target genes in the immune system based on the Reactome database, combined with a systematic literature search for "ncRNA and exercise". Literature searches were based on PubMed, Web of Science, and SPORTDiscus; and miRNA databases were filtered for targets validated by in vitro experimental data. Studies were eligible if they reported on exercise-based interventions in healthy humans. After duplicate removal, 95 studies were included reporting on 164 miRNAs, which were used for the qualitative synthesis. Six studies reporting on long-noncoding RNAs (lncRNAs) or circular RNAs were also identified. Results were analyzed using ordering tables that included exercise modality (endurance/resistance exercise), acute or chronic interventions, as well as the consistency in reported change between studies. Evaluation criteria were defined as "validated" with 100% of ≥3 independent studies showing identical direction of regulation, "plausible" (≥80%), or "suggestive" (≥70%). For resistance exercise, upregulation of miR-206 was validated while downregulation of miR-133a appeared plausible. For endurance exercise, 15 miRNAs were categorized as validated, with 12 miRNAs being consistently elevated and 3 miRNAs being downregulated, most of them after acute exercise training. In conclusion, our approach provides evidence that miRNAs play a major role in exercise-induced effects on the innate and adaptive immune system by targeting different pathways affecting immune cell distribution, function, and trafficking as well as production of (anti-)inflammatory cytokines. miRNAs miR-15, miR-29c, miR-30a, miR-142/3, miR-181a, and miR-338 emerged as key players in mediating the immunomodulatory effects of exercise predominantly after acute bouts of endurance exercise.

Impact of exercise on markers of B cell-related immunity: A systematic review

BACKGROUND

B cells represent a crucial component of adaptive immunity that ensures long-term protection from infection by generating pathogen-specific immunoglobulins. Exercise alters B cell counts and immunoglobulin levels, but evidence-based conclusions on potential benefits for adaptive immunity are lacking. This systematic review assessed current literatures on the impact of acute exercise and exercise training on B cells, immunoglobulins, and markers of secretory immunity in human biofluids.

METHODS

According to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, MEDLINE, Web of Science, and Embase were searched on March 8, 2023. Non-randomized controlled trials and crossover trials investigating the impact of acute exercise or exercise training on B cell counts and proportions, immunoglobulin levels, salivary flow rate, or secretory immunoglobulin A secretion rate were included. Quality and reporting of exercise training studies were assessed using the Tool for the Assessment of Study Quality and reporting in Exercise. Study characteristics, outcome measures, and statistically significant changes were summarized tabularly.

RESULTS

Of the 67 eligible studies, 22 applied acute exercise and 45 applied exercise training. All included outcomes revealed significant alterations over time in acute exercise and exercise training context, but only a few investigations showed significant differences compared to control conditions. Secretory and plasma immunoglobulin A levels were most consistently increased in response to exercise training.

CONCLUSION

B cell-related outcomes are altered by acute exercise and exercise training, but evidence-based conclusions cannot be drawn with high confidence due to the large heterogeneity in populations and exercise modalities. Well-designed trials with large sample sizes are needed to clarify how exercise shapes B cell-related immunity.

Exercise and osteoimmunology in bone remodeling

Bones can form the scaffolding of the body, support the organism, coordinate somatic movements, and control mineral homeostasis and hematopoiesis. The immune system plays immune supervisory, defensive, and regulatory roles in the organism, which mainly consists of immune organs (spleen, bone marrow, tonsils, lymph nodes, etc.), immune cells (granulocytes, platelets, lymphocytes, etc.), and immune molecules (immune factors, interferons, interleukins, tumor necrosis factors, etc.). Bone and the immune system have long been considered two distinct fields of study, and the bone marrow, as a shared microenvironment between the bone and the immune system, closely links the two. Osteoimmunology organically combines bone and the immune system, elucidates the role of the immune system in bone, and creatively emphasizes its interdisciplinary characteristics and the function of immune cells and factors in maintaining bone homeostasis, providing new perspectives for skeletal-related field research. In recent years, bone immunology has gradually become a hot spot in the study of bone-related diseases. As a new branch of immunology, bone immunology emphasizes that the immune system can directly or indirectly affect bones through the RANKL/RANK/OPG signaling pathway, IL family, TNF-α, TGF-β, and IFN-γ. These effects are of great significance for understanding inflammatory bone loss caused by various autoimmune or infectious diseases. In addition, as an external environment that plays an important role in immunity and bone, this study pays attention to the role of exercise-mediated bone immunity in bone reconstruction.

HIIT Induces Stronger Shifts within the Peripheral T Cell Compartment Independent of Sex

Acute exercise induces changes within the T-cell compartment, especially in cytotoxic CD8+ memory subsets, depending on exercise intensity and duration. It is unclear whether exercise-induced changes in major T-cell subsets differ in response to acute high-intensity interval training (HIIT) or moderate-intensity continuous training (MICT) and whether sex-specific effects exist. Twenty-four recreationally active runners (females: n=12, 27.8±4.1years, 54.4±4.6 ml*kg-1*min-1; males: n=12, 31.6±3.8years, 58.9±7.7 ml*kg-1*min-1) participated in this randomized controlled crossover study, and conducted an energy- and duration-matched HIIT and MICT session. Blood was sampled before (T1), immediately (T2) and 1 h after exercise (T3). Flow cytometry was used to identify T-cell populations. HIIT decreased the proportion of CD8+ T-cells more pronounced at T3 compared to MICT (p=0.007), induced a significantly stronger increase in the CD8+ effector memory (TEM) cell proportion at T2 (p=0.032), and decreased CD4+ central memory proportion more pronounced at T2 (p=0.029). A decrease below baseline CD8+ TEM proportion at T3 was observed only after HIIT (p<0.001). No interaction effects between sexes were revealed. Taken together, HIIT represents a more potent stimulus to induce shifts mainly within the cytotoxic CD8+ T-cell compartment, thereby giving implications to investigate the role of HIIT on the cell´s effector phenotype and function in more detail.

Intensity- and time-matched acute interval and continuous endurance exercise similarly induce an anti-inflammatory environment in recreationally active runners: focus on PD-1 expression in Tregs and the IL-6/IL-10 axis

PURPOSE

Acute exercise elicits a transient anti-inflammatory state during the early recovery period. Since recent studies reported on regimen-specific effects on immune-related humoral factors and cellular subsets, this study compared the effects of intensity- and time-matched acute interval and continuous exercise on peripheral anti-inflammatory cellular and humoral immune parameters with a particular focus on the PD-1 expression in CD4+ regulatory T cells (Tregs).

METHODS

Twenty-four recreationally active runners (age: 29.7 ± 4.3 years, BMI: 22.2 ± 2.4, VO2peak: 56.6 ± 6.4 ml × kg-1 × min-1) participated in this crossover RCT. Each subject conducted a moderate continuous (MCE) and a high-intensity interval exercise (HIIE) session in a counterbalanced design. Blood was drawn before, immediately after, and 1 h after exercise. Treg subsets and levels of PD-1 and Foxp3 were assessed by flow cytometry. Serum levels of IL-10 and IL-6 were quantified by ELISA.

RESULTS

PD-1 levels on Tregs increased within the recovery period after HIIE (p < .001) and MCE (p <  0.001). Total counts of Tregs (HIIE: p = 0.044; MCE: p = .021), naïve Tregs (HIIE: p  < 0.001; MCE: p  < 0.001), and PD-1+ effector Tregs (eTregs) (HIIE: p = .002) decreased 1 h after exercise. IL-10 increased 1 h after HIIE (p < 0.001) and MCE (p = 0.018), while IL-6 increased immediately after both HIIE (p = 0.031) and MCE (p = 0.021). Correlations between changes in IL-6 and IL-10 (p = 0.017, r = 0.379) and baseline VO2peak and Treg frequency (p = 0.002, r = 0.660) were identified.

CONCLUSION

This is the first study that investigates PD-1 expression in circulating Tregs after acute exercise, revealing an increase in PD-1 levels on eTregs during the early recovery period after intensity- and time-matched HIIE and MCE. Future studies are needed to investigate the PD-1 signalosome in eTregs, together with the expression of key effector molecules (i.e., IL-10, TGF-β, IL-35, CTLA-4) to elucidate PD-1-dependent changes in cellular function. Based on changes in serum cytokines, this study further reveals a regimen-independent establishment of an anti-inflammatory milieu and underpins the role of the IL-6/IL-10 axis.

Highlighting the idea of exerkines in the management of cancer patients with cachexia: novel insights and a critical review

BACKGROUND

Exerkines are all peptides, metabolites, and nucleic acids released into the bloodstream during and after physical exercise. Exerkines liberated from skeletal muscle (myokines), the heart (cardiokines), liver (hepatokines), white adipose tissue (adipokines), brown adipose tissue (batokines), and neurons (neurokines) may benefit health and wellbeing. Cancer-related cachexia is a highly prevalent disorder characterized by weight loss with specific skeletal muscle and adipose tissue loss. Many studies have sought to provide exercise strategies for managing cachexia, focusing on musculoskeletal tissue changes. Therefore, understanding the responses of musculoskeletal and other tissue exerkines to acute and chronic exercise may provide novel insight and recommendations for physical training to counteract cancer-related cachexia.

METHODS

For the purpose of conducting this study review, we made efforts to gather relevant studies and thoroughly discuss them to create a comprehensive overview. To achieve this, we conducted searches using appropriate keywords in various databases. Studies that were deemed irrelevant to the current research, not available in English, or lacking full-text access were excluded. Nevertheless, it is important to acknowledge the limited amount of research conducted in this specific field.

RESULTS

In order to obtain a comprehensive understanding of the findings, we prioritized human studies in order to obtain results that closely align with the scope of the present study. However, in instances where human studies were limited or additional analysis was required to draw more robust conclusions, we also incorporated animal studies. Finally, 295 studies, discussed in this review.

CONCLUSION

Our understanding of the underlying physiological mechanisms related to the significance of investigating exerkines in cancer cachexia is currently quite basic. Nonetheless, this demonstrated that resistance and aerobic exercise can contribute to the reduction and control of the disease in individuals with cancer cachexia, as well as in survivors, by inducing changes in exerkines.

Diabetes, metformin use and risk of non-Hodgkin's lymphoma in postmenopausal women: A prospective cohort analysis in the Women's Health Initiative

Epidemiologic evidence is limited about associations between T2DM, metformin, and the risk of non-Hodgkin's lymphoma (NHL). We aimed to examine associations between T2DM, metformin, and the risk of NHL in the Women's Health Initiative (WHI) Study. Information on T2DM status (diabetes status/types of antidiabetic drug use/diabetes duration) from study enrollment and during follow-up were assessed. Hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated to evaluate associations of T2DM status with risks of overall NHL and its three major subtypes [diffuse large B-cell lymphoma (DLBCL, n = 476), follicular lymphoma (FL, n = 301) and chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL, n = 136)] based on multivariable-adjusted Cox proportional hazards models. During a median follow-up of 18.86 years (range, 0.01-25.13; SD ± 6.55), a total of 1637 women developed NHL among 147 885 postmenopausal women. Women with T2DM and with self-reported oral medication use had 38% and 55% higher risk of DLBCL, respectively [multivariable-adjusted model HR = 1.38, 95% CI (1.06-1.81) and HR = 1.55, 95% CI (1.16-2.06)] compared to the reference group (nondiabetics/untreated diabetes). Risks of NHL and DLBCL [multivariable-adjusted model: HR = 1.28, 95% CI (1.06-1.54) and HR = 1.56, 95% CI (1.13-2.14), respectively] were significantly higher in associations with relatively short duration (≤7 years) of diabetes, compared to reference group. Additionally, an increased risk of DLBCL [HR = 1.76, 95% CI (1.13-2.75)] was found in metformin users compared to the reference group. Postmenopausal women who had T2DM, who were oral antidiabetic drug users, especially metformin, and who had a shorter diabetes duration may have higher risks of DLBCL. Further well-designed research is needed to confirm our findings.

Regular Voluntary Running is Associated with Increased Tumor Vascularization and Immune Cell Infiltration and Decreased Tumor Growth in Mice

Tumors present dysfunctional vasculature that limits blood perfusion and hinders immune cells delivery. We aimed to investigate if regular voluntary running promotes tumor vascular remodelling, improves intratumoral immune cells infiltration and inhibits tumor growth. Tumors were induced in C57BL/6 male mice (n=28) by subcutaneous inoculation in the dorsal region with a suspension of RM1 cells (1.5×10⁵ cells/500 µL PBS) and randomly allocated into two groups: sedentary (n=14) and voluntarily exercised on a wheel (n=14). Seven mice from each group were sacrificed 14 and 28 days after cells' inoculation to evaluate tumor weight, microvessel density, vessels' lumen regularity and the intratumoral quantity of NKG2D receptors, CD4⁺and CD8⁺T cells, by immunohistochemistry. The statistical inference was done through a two-way ANOVA. Exercised mice developed smaller tumors at 14 (0.17±0.1 g vs. 0.48±0.2 g, p<0.05) and 28 (0.92±0.7 g vs. 2.09±1.3 g, p<0.05) days, with higher microvessel density (21.20±3.2 vs. 15.86±4.0 vessels/field, p<0.05), more regular vessels' lumen (1.06±0.2 vs. 1.43±0.2, p<0.05), and higher CD8⁺T cells (464.95±48.0 vs. 364.70±49.4 cells/mm², p<0.01), after 28 days. NKG2D expression was higher in exercised mice at 14 (263.27±25.8 cells/mm², p<0.05) and 28 (295.06±56.2 cells/mm², p<0.001) days. Regular voluntary running modulates tumor vasculature, increases immune cells infiltration and attenuates tumor growth, in mice.

Vitamin D, exercise, and immune health in athletes: A narrative review

Vitamin D exerts important extra-skeletal effects, exhibiting an exquisite immune regulatory ability, affecting both innate and adaptive immune responses through the modulation of immunocyte function and signaling. Remarkably, the immune function of working skeletal muscle, which is fully recognized to behave as a secretory organ with immune capacity, is under the tight control of vitamin D as well. Vitamin D status, meaning hormone sufficiency or insufficiency, can push toward strengthening/stabilization or decline of immune surveillance, with important consequences for health. This aspect is particularly relevant when considering the athletic population: while exercising is, nowadays, the recommended approach to maintain health and counteract inflammatory processes, “too much” exercise, often experienced by athletes, can increase inflammation, decrease immune surveillance, and expose them to a higher risk of diseases. When overexercise intersects with hypovitaminosis D, the overall effects on the immune system might converge into immune depression and higher vulnerability to diseases. This paper aims to provide an overview of how vitamin D shapes human immune responses, acting on the immune system and skeletal muscle cells; some aspects of exercise-related immune modifications are addressed, focusing on athletes. The crossroad where vitamin D and exercise meet can profile whole-body immune response and health.

Relationship between leisure-time physical activity and depressive symptoms under different levels of dietary inflammatory index

Depressive symptoms are major public health problems. Leisure-time Physical activity (LPA) and dietary inflammatory preference are emerging factors that tends to affect the mental health status. There is limited evidence regarding the joint influence of LPA and dietary status on the prevalence of depression. This study was a cross-sectional study, which used a nationwide represented sample from the National Health and Nutrition Examination Survey (NHANES) to assess the relationship among LPA, diet status and depression. Depression and LPA status was reported by the 9-item Patient Health Questionnaire (PHQ-9) and Physical Activity Questionnaire (PAQ), respectively. To assess dietary inflammatory preferences, dietary inflammatory index (DII) was applied based on a 24-h dietary recall interview. A total of 11,078 subjects was included in this study and weighted participants were 89,682,020. Weighted multivariable linear regression showed that DII was negatively associated with LPA after full adjustment, with β (95% CI): −0.487 (−0.647, −0.327). Weighted multivariable logistic regression showed that LPA was significantly associated with depressive symptoms after full adjustment, with odds ratios OR (95% CIs): 0.986 (0.977, 0.995). By DII stratification analysis, this phenomenon was also existed in groups with anti-inflammatory diet. Mediation effect analysis was further performed, which showed that DII significantly mediating the association between LPA and depression with proportion mediated as 3.94%. Our findings indicated the mediating role of DII in the association between LPA condition and incident depression. More well-designed studies are still needed to validate the causal relationship.

Resistance training and clinical status in patients with postdischarge symptoms after COVID-19: protocol for a randomized controlled crossover trial "The EXER-COVID Crossover Study"

BACKGROUND

Physical exercise induces a coordinated response of multiple organ systems, including the immune system. In fact, it has been proposed that physical exercise may modulate the immune system. However, the potential effect of an exercise program on COVID-19 survivors has not been investigated. Thus, the aim of this study is to evaluate the modifications in immunological parameters, physical condition, inflammatory profile, and perceived persistent symptoms after 6 weeks of supervised resistance training (RT), in addition to the standard care on the clinical status of patients with persistent COVID-19 symptoms. The objective of this protocol is to describe the scientific rationale in detail and to provide information about the study procedures.

METHODS/DESIGN

A total of 100 patients with postdischarge symptoms after COVID-19 will be randomly allocated into either a group receiving standard care (control group) or a group performing a multicomponent exercise program two times a week over a period of 6 weeks. The main hypothesis is that a 6-week multicomponent exercise program (EXER-COVID Crossover Study) will improve the immunological and inflammatory profile, physical condition, and persistent perceived symptoms (fatigue/tiredness, musculoskeletal pain, and shortness of breath) in patients with postdischarge symptoms after COVID-19.

DISCUSSION

Our results will provide insights into the effects of a multicomponent exercise program on immunological parameters, physical condition, inflammatory profile, and persistent perceived symptoms in patients with postdischarge symptoms after COVID-19. Information obtained by this study will inform future guidelines on the exercise training rehabilitation of patients with postdischarge symptoms after COVID-19.

TRIAL REGISTRATION

NCT04797871 , Version 2. Registered on March 15, 2021.

Physical Exercise in the Context of Air Pollution: An Emerging Research Topic

Physical exercise (PE) brings physiological benefits to human health; paradoxically, exposure to air pollution (AP) is harmful. Hence, the combined effects of AP and PE are interesting issues worth exploring. The objective of this study is to review literature involved in AP-PE fields to perform a knowledge-map analysis and explore the collaborations, current hotspots, physiological applications, and future perspectives. Herein, cluster, co-citation, and co-occurrence analysis were applied using CiteSpace and VOSviewer software. The results demonstrated that AP-PE domains have been springing up and in rapid growth since the 21st century. Subsequently, active countries and institutions were identified, and the productive institutions were mainly located in USA, China, UK, Spain, and Canada. Developed countries seemed to be the major promoters. Additionally, subject analysis found that environmental science, public health, and sports medicine were the core subjects, and multidimensional communications were forming. Thereafter, a holistic presentation of reference co-citation clusters was conducted to discover the research topics and trace the development focuses. Youth, elite athletes, and rural population were regarded as the noteworthy subjects. Commuter exposure and moderate aerobic exercise represented the common research context and exercise strategy, respectively. Simultaneously, the research hotspots and application fields were elaborated by keyword co-occurrence distribution. It was noted that physiological adaptations including respiratory, cardiovascular, metabolic, and mental health were the major themes; oxidative stress and inflammatory response were the mostly referred mechanisms. Finally, several challenges were proposed, which are beneficial to promote the development of the research field. Molecular mechanisms and specific pathways are still unknown and the equilibrium points and dose-effect relationships remain to be further explored. We are highly confident that this study provides a unique perspective to systematically and comprehensively review the pieces of AP-PE research and its related physiological mechanisms for future investigations.

Why exercise has a crucial role in cancer prevention, risk reduction and improved outcomes

INTRODUCTION

Exercise is one of several factors known to lower the risk of developing cancer, as well as improve outcomes in patients already diagnosed. People who exercise after cancer have lower rates of cancer complications, treatment toxicities, relapse and improved survival. This review highlights the supportive data and biochemical processes, which explain these potential benefits.

SOURCES OF DATA

PubMed, Embase, Medline and Cochrane libraries were searched for papers which addressed the effects of exercise and physical activity on cancer for this review. The search terms used were physical activity, exercise and cancer up to February 2021. We also referred to the background research required for international exercise intervention study involving men with prostate cancer (INTERVAL-GAP4) and scrutinized references within the robust papers published on this subject to ensure we did not miss any clinically studies. One hundred and eighty eight papers were included.

AREAS OF AGREEMENT

Exercise programmes mitigate many of the complications and risks associated with cancer, particularly thromboembolism, fatigue, weight gain, arthralgia, cognitive impairment and depression.

AREAS OF CONTROVERSY

Molecular and biomarker changes, resulting from exercise, suggest that exercise elicits beneficial changes in insulin-related pathways, down-regulates inflammation and serum oestrogen levels, and enhances oxidative, immune and cellular repair pathways. Nonetheless, the evidence remains preliminary.

GROWING POINTS

The timing, intensity and challenges of prehabilitation, adjunct and rehabilitation exercise programmes are being increasingly understood but their implementation remains sporadic.

AREAS FOR DEVELOPING RESEARCH

More robust clinical trial data are needed to substantiate a causal effect of exercise on overall and cancer-specific survival. These studies are ongoing. Research evaluating the most cost-efficient ways of incorporating prehabilitation, adjunct and rehabilitation programmes into routine practice would be helpful to funding bodies and health care strategists.

Heat stress response in slick vs normal-haired Criollo Limonero heifers in a tropical environment

To assess the effect of hair type on the heat stress response, 20 Criollo Limonero heifers with slick (n = 11) or normal hair (n = 9) were studied. Under a high temperature-humidity index (THI) environment, heat stress response was assessed through physiological variables that included respiration rate (RR), heart rate (HR), ruminal frequency (RMF), rectal temperature (RT), saliva pH (SPH), and lymphocyte count (LC) in the morning (5:00 AM, 27.4 °C, 64% relative humidity, THI = 77) and afternoon (1:00 PM, 34.5 °C, 70% relative humidity, THI = 88). A case-control study using a split plot design was used. Data were analyzed using ANOVA (PROC MIXED SAS 2010) and a statistical model comprising the fixed effects of hair length, sampling hour, interaction of hair length by sampling hour, and the random effect of animal nested within hair type on physiological variables associated with heat stress response. Sampling hour influenced (P < 0.0001) RR, RT, and (P < 0.003) SPH. Hair length influenced RR (P < 0.01) and RT (P < 0.04) and tended to influence LC (P < 0.07). The interaction of sampling hour by hair influenced RR (P < 0.04), RT (P < 0.0002), and both SPH and LC (P < 0.05). During afternoon hours, slick-haired heifers had lower values for RR (81 ± 4.2 vs 102 ± 4.7 bpm; P < 0.01), RT (39.5 ± 0.1 vs 40.3 ± 0.1 C°; P < 0.002), and LC (60 ± 3.2 vs 72.3 ± 3.6; P < 0.09) than normal-haired heifers. In normal-haired heifers, SPH increased during afternoon compared to morning-hours (8.66 ± 0.1 vs 9.11 ± 0.1; P < 0.04). It was concluded that slick-coated heifers exhibited an enhanced capability to cope with heat stress compared to normal-haired heifers likely due to an enhanced capacity for heat dissipation.

A qualitative mathematical model of the immune response under the effect of stress

In recent decades, many studies have been developed in psychoneuroimmunology that associate stress, arising from multiple different sources and situations, to changes in the immune system, from the medical or immunological point of view as well as from the biochemical one. In this paper, we identify important behaviors of this interplay between the immune system and stress from medical studies and seek to represent them qualitatively in a paradigmatic, yet simple, mathematical model. To that end, we develop an ordinary differential equation model with two equations, for infection level and immune system, respectively, which integrates the effects of stress as an independent parameter. In addition, we perform a geometric analysis of the model for different stress values as well as the corresponding bifurcation analysis. In this context, we are able to reproduce a stable healthy state for little stress, an oscillatory state between healthy and infected states for high stress, and a "burn-out" or stable sick state for extremely high stress. The mechanism between the different dynamical regimes is controlled by two saddle-node in cycle bifurcations. Furthermore, our model is able to capture an induced infection upon dropping from moderate to low stress, and it predicts increasing infection periods upon increasing stress before eventually reaching a burn-out state.

Effect of Multi-Strain Probiotic Supplementation on URTI Symptoms and Cytokine Production by Monocytes after a Marathon Race: A Randomized, Double-Blind, Placebo Study

(1) Purpose: Performing strenuous exercises negatively impacts the immune and gastrointestinal systems. These alterations cause transient immunodepression, increasing the risk of minor infections, especially in the upper respiratory tract. Recent studies have shown that supplementation of probiotics confers benefits to athletes. Therefore, the objective of the current study was to verify the effects of probiotic supplementation on cytokine production by monocytes and infections in the upper respiratory tract after an acute strenuous exercise. (2) Methods: Fourteen healthy male marathon runners received either 5 billion colony forming units (CFU) of a multi-strain probiotic, consisting of 1 billion CFU of each of Lactobacillus acidophilus LB-G80, Lactobacillus paracasei LPc-G110, Lactococcus subp. lactis LLL-G25, Bifidobacterium animalis subp. lactis BL-G101, and Bifidobacterium bifidum BB-G90, or a placebo for 30 days before a marathon. Plasma cytokines, salivary parameters, glucose, and glutamine were measured at baseline, 24 h before, immediately after, and 1 h after the race. Subjects self-reported upper respiratory tract infection (URTI) using the Wisconsin Upper Respiratory Symptom Survey (WURSS-21). The statistical analyses comprised the general linear model (GLM) test followed by the Tukey post hoc and Student's t-test with p < 0.05. (3) Results: URTI symptoms were significantly lower in the probiotic group compared to placebo. The IL-2 and IL-4 plasma cytokines were lower 24 h before exercise, while the other cytokines showed no significant differences. A lower level of IL-6 produced by monocytes was verified immediately after the race and higher IL-10 at 1 h post. No differences were observed in salivary parameters. Conclusion: Despite the low number of marathoners participating in the study, probiotic supplementation suggests its capability to preserve the functionality of monocytes and mitigate the incidence of URTI.

Impact of Olive Oil Supplement Intake on Dendritic Cell Maturation after Strenuous Physical Exercise: A Preliminary Study

Physical exercise is known to have a dose-dependent effect on the immune system and can result in an inflammatory process in athletes that is proportional to the intensity and duration of exertion. This inflammatory process can be measured by cell markers such as dendritic cells (DCs), which, in humans, consist of the myeloid DC (mDCs) and plasmacytoid DC (pDCs) subpopulations. The aim of this study was to measure DC differentiation to determine the possible anti-inflammatory effects, after intense aerobic effort, of the intake of a 25 mL extra-virgin olive oil supplement. Three healthy sports-trained subjects went through resistance exercise loads on two days separated by a week: on one day after active supplement intake and on the other day after placebo supplement intake. The results show that the highest increase (77%) in the percentage of mDCs as a proportion of pDCs was immediately after testing. Independently of the supplement taken, mature mDCs showed a decreasing trend between the test one hour after and 24 h after testing ended. Nevertheless, measured in terms of the coefficient of variation, only the decrease (46%) for extra-virgin olive oil supplementation was statistically significant (95% CI: 30-62%; p = 0.05). In conclusion, an extra-virgin olive oil supplement could reduce the inflammatory impact of intense aerobic effort and improve recovery at 24 h.

The Impact of Nationality on the Psychophysiological Stress Response and Academic Fulfilment in the Final Degree Dissertation

The aims of this study were: i. to analyze the effect of nationality on the psychophysiological stress response of physiotherapy last year students in their final degree dissertations; and ii. to analyze the relationship between the stress response and academic results according to nationality. We evaluated the autonomic stress response, cortical arousal, distress subjective perception, and objective and subjective academic fulfilment in Spanish, Italian, and French physiotherapy students during their final degree dissertation. Results showed a large anticipatory anxiety response before the dissertation in the three student groups. Only the Spanish group showed an increased tendency in the habituation process, reducing the psychophysiological stress response during the dissertation, while the Italian and French groups maintained a large sympathetic activation until the end of the dissertation. Cortical arousal and subjective perception of distress were similar in the three nationalities. In addition, no correlation between academic fulfilment and autonomic modulation was found. We concluded that there was no nationality effect in the psychophysiological stress response of physiotherapy last year students in their final degree dissertation, all of them showing a large anticipatory anxiety response.

Investigation of the natural supplement IQP-AS-119 for the prevention of upper respiratory tract infections in marathon race participants: A randomized, double-blind, placebo-controlled pilot study

Intense and prolonged exercise leads to immune suppression, causing upper respiratory tract infections (URTI). A proprietary standardized dietary supplement, IQP-AS-119 has been previously developed to aid immune responses under such conditions. The current randomized, double-blind, placebo-controlled pilot study aimed to investigate the effects of IQP-AS-119 on marathon runners. A total of 80 participants were randomized equally into groups receiving either placebo (P group) or IQP-AS-119 (V group) treatment, starting 3 weeks before and for 14 days after the marathon. Benefit assessment was performed using different questionnaires. Post-marathon, the V and P groups reported 1±2.38 and 2.11±3.25 days with upper respiratory tract symptoms (URTS), respectively (P=0.038). During the 14 days post-marathon, 20.0% of the participants in the V group compared with 44.4% in the P group reported URTS (P=0.042). The V group reported significantly milder URTS compared with the P group on Days 9, 12, 13 and 14 post-marathon (P<0.05). The total Perceived Stress Questionnaire-20 score on days 2-14 were significantly lower for the V group compared with the P group (P=0.035). In the Short Form 12 Health Survey, the V group exhibited significant improvement in mental composite score on days -5 to 14 compared with the P group (P=0.038). In the overall treatment effect assessment, there were no statistically significant differences between the groups. The IQP-AS-119 was rated 'very good' or 'good' by investigators and participants, respectively, for 71 and 65% of the participants. The tolerability of IQP-AS-119 was rated as 'very good' or 'good' by both investigators and 95% of participants. No clinically relevant differences were observed between groups regarding adverse events or other safety parameters. Therefore, IQP-AS-119 was demonstrated to reduce the incidence and severity of URTI in marathon runners. Given its good tolerability profile, IQP-AS-119 may be a good nutritional supplement for the reduction of URTS in susceptible individuals.

Human immune cell mobilization during exercise: effect of IL-6 receptor blockade

NEW FINDINGS

What is the central question of this study? Does blockade of the IL-6 receptor by tocilizumab inhibit immune cell mobilization to the blood stream in humans during an acute bout of exercise? What is the main finding and its importance? Blockade of IL-6 receptor signalling by tocilizumab attenuates mobilization of NK cells and dendritic cells to the blood stream during exercise. This implies an inhibitory effect of tocilizumab on the innate immune response to physical stress, which could be considered in clinical settings.

ABSTRACT

Immune cells are recruited from their storage organs and the endothelial walls to the blood stream in response to physiological stress. This is essential for the recognition and clearing of infected, transformed or damaged cells. One of the most potent stimuli to recruit immune cells to the circulation is exercise. Accordingly, exercise has proven beneficial in disease settings, such as cancer and diabetes. Interleukin-6 (IL-6) is released from contracting skeletal muscle in response to exercise, and rodent studies have established a link between exercise-induced IL-6 and recruitment of natural killer (NK) cells. Whether exercise-induced IL-6 is involved in regulating NK cell mobilization in humans is unclear. This study explored the effect of IL-6 receptor blockade on immune cell mobilization during an acute bout of exercise in humans. In a randomized, placebo-controlled clinical study, abdominally obese humans receiving placebo infusions or tocilizumab infusions performed an acute bout of exercise before and after the intervention. Immune cell recruitment was measured by flow cytometry. IL-6 receptor blockade attenuated the increase of NK cells by 53% (mean difference -0.49 (95% CI: -0.89 to -0.08) × 10⁹ cells L^-1 , P < 0.001) and dendritic cells by 66% (mean difference -0.14 (95% CI: -0.28 to 0.010) × 10⁹ cells L^-1 , P < 0.001) induced by an acute bout of exercises. No changes were observed for T cells, monocytes and neutrophils. Treatments which interact with the exercise-mediated immune surveillance provide relevant clinical information in pursuing the 'exercise as medicine' concept.

Chronic skin disease and levels of physical activity in 17 777 Spanish adults: a cross-sectional study

BACKGROUND

To date there is limited literature on the prevalence of chronic skin conditions and its association with levels of physical activity (PA) in Spain.

AIM

To determine the prevalence of chronic skin disease and to compare levels of PA between people with and without chronic skin disease in a large representative sample of Spanish adults aged 15-69 years.

METHODS

Data from the Spanish National Health Survey 2017 were analysed. Chronic skin disease was assessed using a yes/no question. PA was measured using the short form of the International Physical Activity Questionnaire. Total PA metabolic equivalent of task min/week were calculated, and PA was included in the analyses as a continuous and a five-category variable.

RESULTS

This cross-sectional study included 17 777 adult participants (52.0% women; mean ± SD age 45.8 ± 14.1 years), of whom 940 (5.3%) had chronic skin disease. After adjusting for several potential confounders, there was a negative association between chronic skin disease and PA (OR = 0.87, 95% CI 0.76-1.00, P = 0.05), which was significant for men (OR = 0.76, 95% CI 0.62-0.93, P = 0.01) but not for women (OR = 0.97, 95% CI 0.81-1.16, P = 0.72).

CONCLUSIONS

In this large representative sample of Spanish adults, the prevalence of chronic skin disease was low. Levels of PA were lower in men with than in men without chronic skin conditions, but this association was not seen in women.

Biochemical markers after the Norseman Extreme Triathlon

Prolonged exercise is known to cause changes in common biomarkers. Occasionally, competition athletes need medical assistance and hospitalisation during prolonged exercise events. To aid clinicians treating patients and medical teams in such events we have studied common biomarkers after at The Norseman Xtreme Triathlon (Norseman), an Ironman distance triathlon with an accumulated climb of 5200 m, and an Olympic triathlon for comparison. Blood samples were collected before, immediately after, and the day following the Norseman Xtreme Triatlon (n = 98) and Oslo Olympic Triathlon (n = 15). Increased levels of clinical significance were seen at the finish line of the Norseman in white blood cells count (WBC) (14.2 [13.5–14.9] 109/L, p < 0.001), creatinine kinase (CK) (2450 [1620–3950] U/L, p < 0.001) and NT-proBNP (576 [331–856] ng/L, p < 0.001). The following day there were clinically significant changes in CRP (39 [27–56] mg/L, p < 0.001) and Aspartate Aminotransferase (AST) (142 [99–191] U/L, p < 0.001). In comparison, after the Olympic triathlon distance, there were statistically significant, but less clinically important, changes in WBC (7.8 [6.7–9.6] 109/L, p < 0.001), CK (303 [182–393] U/L, p < 0.001) and NT-proBNP (77 [49–88] ng/L, p < 0.01) immediately after the race, and in CRP (2 [1–3] mg/L, p < 0.001) and AST (31 [26–41] U/L, p < 0.01) the following day. Subclinical changes were also observed in Hemoglobin, Thrombocytes, K+, Ca2+, Mg2+, Creatinine, Alanine Aminotransferase and Thyroxine after the Norseman. In conclusion, there were significant changes in biomarkers used in a clinical setting after the Norseman. Of largest clinical importance were clinically significant increased WBC, CRP, AST, CK and NT-proBNP after the Norseman. This is important to be aware of when athletes engaging in prolonged exercise events receive medical assistance or are hospitalised.

Exercise preserves muscle mass and force in a prostate cancer mouse model

The purpose of this study was to examine the effects of exercise in modulating biomarkers of sarcopenia in a treatment naïve transgenic adenocardinoma of the mouse prostate (TRAMP) model. Thirty TRAMP mice were randomized to either exercise (voluntary wheel running) or no-treatment control group for a period of 20 weeks. During necropsy, gastrocnemius muscles and prostate tumors were harvested and weighed. Gastrocnemius concentrations of myostatin, insulin-like growth factor (IGF)-1 and tumor necrosis factor (TNF)-α were quantified. Exercise mice had greater muscle mass than controls (p=0.04). Myostatin was significantly lower in the exercise group compared to controls (p=0.01). Exercise mice maintained forelimb grip force while control mice had a significaint decrease (p=0.01). No significant difference was observed in pre-post all limb grip strength. Further, forelimb and all limb grip strength was negatively associated with tumor mass (p<0.01).

Vitamin C and Neutrophil Function: Findings from Randomized Controlled Trials

Vitamin C is known to support immune function and is accumulated by neutrophils to millimolar intracellular concentrations suggesting an important role for the vitamin in these cells. In this review, the effects of vitamin C, as a mono- or multi-supplement therapy, on neutrophil function were assessed by conducting a systematic review of randomized controlled trials (RCTs). Specifically, trials which assessed neutrophil migration (chemotaxis), phagocytosis, oxidative burst, enzyme activity, or cell death (apoptosis) as primary or secondary outcomes were assessed. A systematic literature search was conducted using the Cochrane Central Register of Controlled Trials, EMBASE, Embase Classic, Joanna Briggs Institute EBP, Ovid MEDLINE®, Ovid MEDLINE® In-Process & Other Non-Indexed Citations, Ovid Nursing Database, CINAHL and PubMed database, which identified 16 eligible RCTs. Quality appraisal of the included studies was carried out using the Cochrane Risk of Bias tool. Three of the studies assessed neutrophil chemotaxis in hospitalised patients or outpatients, two of which showed improved neutrophil function following intravenous vitamin C administration. Ten RCTs assessed neutrophil phagocytosis and/or oxidative burst activity; five were exercise studies, one in smokers, one in myocardial infarction patients and three in healthy volunteers. Two of the multi-supplement studies showed a difference between the intervention and control groups: increased oxidative burst activity in athletes post-exercise and decreased oxidant generation in myocardial infarction patients. Two studies assessed neutrophil enzyme activity; one showed deceased antioxidant enzyme activity in divers and the other showed increased antioxidant enzyme activity in athletes. One final study showed decreased neutrophil apoptosis in septic surgical patients following intravenous vitamin C administration. Overall, 44% of the RCTs assessed in this review showed effects of vitamin C supplementation on neutrophil functions. However, the studies were very heterogeneous, comprising different participant cohorts and different dosing regimens. There were also a number of limitations inherent in the design of many of these RCTs. Future RCTs should incorporate prescreening of potential participants for low vitamin C status or utilize cohorts known to have low vitamin status, such as hospitalized patients, and should also comprise appropriate vitamin C dosing for the cohort under investigation.

Influence of Acute Exercise on DNA Repair and PARP Activity before and after Irradiation in Lymphocytes from Trained and Untrained Individuals

Several studies indicate that acute exercise induces DNA damage, whereas regular exercise increases DNA repair kinetics. Although the molecular mechanisms are not completely understood, the induction of endogenous reactive oxygen species (ROS) during acute exhaustive exercise due to metabolic processes might be responsible for the observed DNA damage, while an adaptive increase in antioxidant capacity due to regular physical activity seems to play an important protective role. However, the protective effect of physical activity on exogenously induced DNA damage in human immune cells has been poorly investigated. We asked the question whether individuals with a high aerobic capacity would have an enhanced response to radiation-induced DNA damage. Immune cells are highly sensitive to radiation and exercise affects lymphocyte dynamics and immune function. Therefore, we measured endogenous and radiation-induced DNA strand breaks and poly (ADP-ribose) polymerase-1 (PARP1) activity in peripheral blood mononuclear cells (PBMCs) from endurance-trained (maximum rate of oxygen consumption measured during incremental exercise V'O2max > 55 mL/min/kg) and untrained (V'O2max < 45 mL/min/kg) young healthy male volunteers before and after exhaustive exercise. Our results indicate that: (i) acute exercise induces DNA strand breaks in lymphocytes only in untrained individuals, (ii) following acute exercise, trained individuals repaired radiation-induced DNA strand breaks faster than untrained individuals, and (iii) trained subjects retained a higher level of radiation-induced PARP1 activity after acute exercise. The results of the present study indicate that increased aerobic fitness can protect immune cells against radiation-induced DNA strand breaks.

Effect of Forced Physical Activity on the Severity of Experimental Colitis in Normal Weight and Obese Mice. Involvement of Oxidative Stress and Proinflammatory Biomarkers

Inflammatory bowel diseases are a heterogeneous group of disorders represented by two major phenotypic forms, Crohn’s disease and ulcerative colitis. Cross talk between adipokines and myokines, as well as changes in intestinal microcirculation, was proposed in pathogenesis of these disorders. C57BL/6 male mice were fed ad libitum for 12 weeks a standard (SD) or high-fat diet (HFD). After the adaptation period, two groups of animals fed SD or HFD were subjected to 6 weeks of the forced treadmill exercise and the experimental colitis was induced in both groups of sedentary and exercising mice fed SD and HFD by intra-colonic administration of 2,4,6-trinitrobenzenesulfonic acid. The disease activity index (DAI), colonic blood flow (CBF), the weight of animals, caloric intake, the mesenteric fad pad, the colonic oxidative stress markers malondialdehyde (MDA), reduced glutathione (GSH), and superoxide dismutase (SOD) activity and intestinal expression and protein content of proinflammatory markers were evaluated. Macroscopic and microscopic colitis in sedentary SD mice was accompanied by a significant fall in CBF and exacerbated in those fed a HFD. The contents of MDA, GSH, and SOD activity were significantly increased in both SD and HFD fed mice with treadmill exercise as compared with sedentary mice. In sedentary HFD mice a significant increase in the intestinal oxidative stress parameters and mucosal expression of IL-1β, TNF-α, IL-17, IFNγ, IL-6, and IL-10 protein were observed and these effects were aggravated in mice subjected to forced treadmill exercise. The mucosal expression of mRNA for TNF-α, IL-1β, iNOS, COX-2, SOD-1, SOD-2, GPx mRNAs, and the hypoxia inducible factor (HIF)-1α protein expression were upregulated in colonic mucosa of treadmill exercising HFD mice with colitis compared with those without exercise. We conclude that forced treadmill running exacerbates the severity of colonic damage in obese mice due to a fall in colonic microcirculation, an increase in oxidative stress, and the rise in expression and activity of proinflammatory biomarkers.

Exercise prehabilitation may lead to augmented tumor regression following neoadjuvant chemoradiotherapy in locally advanced rectal cancer

  Purpose: We evaluate the effect of an exercised prehabilitation programme on tumour response in rectal cancer patients following neoadjuvant chemoradiotherapy (NACRT). Patients and Methods: Rectal cancer patients with (MRI-defined) threatened resection margins who completed standardized NACRT were prospectively studied in a post hoc, explorative analysis of two previously reported clinical trials. MRI was performed at Weeks 9 and 14 post-NACRT, with surgery at Week 15. Patients undertook a 6-week preoperative exercise-training programme. Oxygen uptake (VO2) at anaerobic threshold (AT) wasmeasured at baseline (pre-NACRT), after completion of NACRT and at week 6 (post-NACRT). Tumour related outcome variables: MRI tumour regression grading (ymrTRG) at Week 9 and 14; histopathological T-stage (ypT); and tumour regression grading (ypTRG)) were compared. Results: 35 patients (26 males) were recruited. 26 patients undertook tailored exercise-training with 9 unmatched controls. NACRT resulted in a fall in VO2 at AT -2.0 ml/kg^-1/min^-1(-1.3,-2.6), p < 0.001. Exercise was shown to reverse this effect. VO2 at AT increased between groups, (post-NACRT vs. week 6) by +1.9 ml/kg^-1/min^-1(0.6, 3.2), p = 0.007. A significantly greater ypTRG in the exercise group at the time of surgery was found (p = 0.02). Conclusion: Following completion of NACRT, exercise resulted in significant improvements in fitness and augmented pathological tumour regression.

Psychobiological factors of resilience and depression in late life

In contrast to traditional perspectives of resilience as a stable, trait-like characteristic, resilience is now recognized as a multidimentional, dynamic capacity influenced by life-long interactions between internal and environmental resources. We review psychosocial and neurobiological factors associated with resilience to late-life depression (LLD). Recent research has identified both psychosocial characteristics associated with elevated LLD risk (e.g., insecure attachment, neuroticism) and psychosocial processes that may be useful intervention targets (e.g., self-efficacy, sense of purpose, coping behaviors, social support). Psychobiological factors include a variety of endocrine, genetic, inflammatory, metabolic, neural, and cardiovascular processes that bidirectionally interact to affect risk for LLD onset and course of illness. Several resilience-enhancing intervention modalities show promise for the prevention and treatment of LLD, including cognitive/psychological or mind-body (positive psychology; psychotherapy; heart rate variability biofeedback; meditation), movement-based (aerobic exercise; yoga; tai chi), and biological approaches (pharmacotherapy, electroconvulsive therapy). Additional research is needed to further elucidate psychosocial and biological factors that affect risk and course of LLD. In addition, research to identify psychobiological factors predicting differential treatment response to various interventions will be essential to the development of more individualized and effective approaches to the prevention and treatment of LLD.

Exercise, Immunity, and Illness

It is generally accepted that moderate amounts of exercise improve immune system functions and hence reduce the risk of infection whereas athletes engaged in regular prolonged and/or intensive training have a higher than “normal” incidence of minor infections, especially of the upper respiratory tract (URT, e.g., common cold and influenza). This is likely related to regular acute (and possibly chronic) periods of exercise-induced changes in immune function. URT infections can compromise performance directly if suffered shortly before or during competition or indirectly if suffered at other times via effects on training and/or physiological adaptations. This chapter covers the effects of exercise (acute and chronic), both positive and negative, on immune function and consequent infection risk, and considers the current state-of-the-art for monitoring and assessing this in athletes.

Acute Physiological and Psychological Effects of Qigong Exercise in Older Practitioners

Qigong is a gentle exercise that promotes health and well-being. This study evaluated the acute physiological and psychological effects of one session of qigong exercise in older practitioners. A total of 45 participants (mean age, 65.14 years) were recruited. Meridian electrical conductance, State-Trait Anxiety Inventory (STAI), heart rate variability (HRV), and Short Form 36 (SF-36) were evaluated and compared before and after one session of qigong exercise. The results revealed that the electrical conductance of all meridians, except spleen and bladder meridians, increased significantly (p < 0.05). Compared with baseline values, upper to lower body ratio and sympathetic/vagal index were significantly improved and closer to 1 (p = 0.011 and p = 0.007, resp.). STAI-S and STAI-T scores decreased significantly (p < 0.001 and p = 0.001, resp.). The RR interval of HRV decreased significantly (p = 0.035), a significant positive correlation was observed between kidney meridian electrical conductance and SF-36 physical scores (r = 0.74, p = 0.018), and a positive correlation was observed between pericardium meridian electrical conductance and SF-36 mental scores (r = 0.50, p = 0.06). In conclusion, one session of qigong exercise increased meridian electrical conductance, reduced anxiety, and improved body and autonomic nervous system balance. These findings provide scientific evidence for acute physiological and psychological effects of qigong exercise in older practitioners.

The effect of intrathecal injection of irisin on pain threshold and expression rate of GABAB receptors in peripheral neuropathic pain model

BACKGROUND

and aim: Irisin is a new myokine that is secreted by myocytes during exercise, and plays a role in creating the beneficial effects of exercise on metabolism. Considering the benefits of exercise in reducing pain, this study was carried out to determine the probable effect of irisin on neuropathic pain in the chronic constriction injury (CCI) model in male rats.

METHODS

To induce neuropathic pain CCI model was used. Animals were divided into groups of control, CCI, sham, CCI + vehicle, and CCI + irisin. Animals that had undergone CCI were divided into 6 groups and each received a different intrathecal dose of irisin (30, 10, 3, 1, 0.3, and 0.1 μg/kg) via intrathecal administration. To evaluate the chronic effect of irisin, its effective dose was injected for 14 days in another group of animals. At the end of the experiment, animals were ranscardially perfused and their spinal cord tissue was prepared for immunohistochemical and hematoxylin-eosin staining.

RESULTS

The results showed that in acute intrathecal injection of irisin, 1 μg/kg dose has the highest analgesic effect compared to other doses. Nevertheless, in chronic administration of irisin with 1 μg/kg dose, no analgesic effect was detected. In addition, irisin administration could not increase the expression level of GABAB1 and B2 or prevent the decline in the number of neurons.

CONCLUSION

The findings of the present study showed that acute administration of Irisin increases the pain threshold, but the chronic injection of resin does not have an effect on pain reduction and the expression of GABA receptors and it seems that this peptide is not a proper replacement for exercise in patients with neuropathic pain, who cannot exercise.

The inflammation paradox: Why are Tsimane protected against Western diseases while Westerners are not?

We here describe two apparent paradoxes concerning high CRP levels and NCD risk. One has emerged from observational studies in the Amazon region showing that the indigenous Tsimane in Bolivia appear protected against non-communicable diseases (NCDs) such as obesity, type 2 diabetes, and cardiovascular diseases despite increased inflammatory markers. These findings stand in contrast to Western societies, where an increasing body of evidence demonstrates that low-grade-inflammation is the driver of NCDs. The second paradox has emerged from two field studies (Eifel studies) conducted in 2013 and 2014 with Westerners who returned to a simulated Palaeolithic lifestyle in a National park for 4 days. We had detected elevated inflammation markers, despite otherwise anti-inflammatory effects of these interventions as indicated by metabolic blood parameters. We here propose three hypotheses for this second inflammatory paradox.

Immune cell response to strenuous resistive breathing: comparison with whole body exercise and the effects of antioxidants

Background/hypothesis

Whole body exercise (WBE) changes lymphocyte subset percentages in peripheral blood. Resistive breathing, a hallmark of diseases of airway obstruction, is a form of exercise for the inspiratory muscles. Strenuous muscle contractions induce oxidative stress that may mediate immune alterations following exercise. We hypothesized that inspiratory resistive breathing (IRB) alters peripheral blood lymphocyte subsets and that oxidative stress mediates lymphocyte subpopulation alterations following both WBE and IRB.

Patients and methods

Six healthy nonathletes performed two WBE and two IRB sessions for 45 minutes at 70% of VO₂ maximum and 70% of maximum inspiratory pressure (Pi_max), respectively, before and after the administration of antioxidants (vitamins E, A, and C for 75 days, allopurinol for 30 days, and N-acetylcysteine for 3 days). Blood was drawn at baseline, at the end of each session, and 2 hours into recovery. Lymphocyte subsets were determined by flow cytometry.

Results

Before antioxidant supplementation at both WBE end and IRB end, the natural killer cell percentage increased, the T helper cell (CD3+ CD4+) percentage was reduced, and the CD4/CD8 ratio was depressed, a response which was abolished by antioxidants only after IRB. Furthermore, at IRB end, antioxidants promoted CD8+ CD38+ and blunted cytotoxic T-cell percentage increase. CD8+ CD45RA+ cell percentage changes were blunted after antioxidant supplementation in both WBE and IRB.

Conclusion

We conclude that IRB produces (as WBE) changes in peripheral blood lymphocyte subsets and that oxidative stress is a major stimulus predominantly for IRB-induced lymphocyte subset alterations.

Acute Strenuous Exercise Induces an Imbalance on Histone H4 Acetylation/Histone Deacetylase 2 and Increases the Proinflammatory Profile of PBMC of Obese Individuals

This study evaluated the response of global histone H4 acetylation (H4ac), histone deacetylase 2 (HDAC2) activity, as well as the production of proinflammatory cytokines and monocyte phenotypes of lean and obese males after exercise. Ten lean and ten obese sedentary men were submitted to one session of strenuous exercise, and peripheral blood mononuclear cells (PBMC) were stimulated in vitro with lipopolysaccharide (LPS). Global H4ac levels, HDAC2 activity in PBMC, and IL-6, IL-8, and TNF-α production were analyzed. Monocyte phenotype was determined in accordance with the expression of CD14 and CD16. At rest, obese individuals presented higher frequency of proinflammatory CD14⁺CD16⁺ monocytes. LPS induced a significant augment in global H4ac and in the production of IL-6, IL-8, and TNF-α mainly in obese individuals. After exercise, the increased production of IL-8 and TNF-α and peripheral frequency of CD14⁺CD16⁺ were observed in both groups. In addition, exercise also induced a significant hyperacetylation of histone H4 and decreased HDAC2 activity in both nonstimulated and LPS-stimulated PBMC of obese individuals. Our data indicate that the obesity impacts on H4ac levels and that strenuous exercise leads to an enhanced chronic low-grade inflammation profile in obesity via an imbalance on H4ac/HDAC2.

The Effect of a 100-km Ultra-Marathon under Freezing Conditions on Selected Immunological and Hematological Parameters

Although moderate exercise is beneficial for the human body and its immune system, exhaustive ultra-endurance performance in cold conditions might be harmful. The aim of this study was to examine the effect of a 100-km ultra-marathon under cold conditions (temperatures from −1°C to +1°C) on selected immunological, biochemical and hematological parameters. Participants were 15 runners (12 men and three women, age 40.3 ± 9.7 years, body mass 67.3 ± 9.0 kg and body height 1.74 ± 0.10 m, mean ± standard deviation). Leukocytes increased (p < 0.01) and, particularly, the number of leucocytes doubled in seven out of 15 athletes. Immature neutrophils, mature neutrophils and monocytes increased (p < 0.02), whereas lymphocytes and eosinophils did not change. IgG increased (p < 0.02), but IgA and IgM remained unchanged. Platelets increased (p < 0.01), whereas red blood cells, hematocrit and hemoglobin did not change. lactate dehydrogenase (LDH) and creatine kinase (CK) increased (p < 0.01), but alanine aminotransferase (ALT) did not change. There was an association between the markers of the acute inflammation of the organism (i.e., neutrophils, immature neutrophils, platelets, and monocytes) and the markers of muscle damage (i.e., CK, platelets, and LDH). There were no relationships among all the markers in relation to upper respiratory tract infections and liver damage. The highest change was noted in the increase of the number of immature neutrophils (1,019.2%) and CK levels (1,077.6%). In summary, this is the first study investigating immunological, hematological and biochemical parameters and showing that running a 100-km ultra-marathon under cold conditions leads to changes in several immunological, biochemical and hematological parameters indicating a severe stress on the body associated with increasing susceptibility to the development of infections.

Influence of polyphenol-rich diet on exercise-induced immunomodulation in male endurance athletes

Stress is associated with increased susceptibility to infection. We investigated if the mechanism involves immunomodulation of dendritic cells and whether this can be inhibited by a polyphenol-rich diet. Blood samples were taken from a total of 100 male endurance athletes at 5 time points around a marathon run: 4 weeks before; 1 week before; and immediately, 24 h, and 72 h after. Participants were randomized into 2 double-blinded groups. One group received a polyphenol-rich beverage during a 3-week training phase before marathon while the other group received a placebo beverage. Flow cytometric analysis of dendritic cell (DC) counts and subpopulation counts (myeloid, plasmocytoid DCs) was performed. Levels of viral antigen presenting toll-like receptor (TLR) 7 messenger RNA was measured by real-time polymerase chain reaction. Marathon running induced a significant increase of circulating myeloid DCs (0.2% vs. 0.33% of whole-blood leukocytes (wbl); p < 0.01) and a significant decrease of plasmozytoid DCs (0.12% vs. 0.03% of wbl; p < 0.01) and TLR7 expression (decline of 60%; p < 0.01). Polyphenol supplementation did not significantly affect mobilization of dendritic cells but showed beneficial effects on regeneration of TLR7 expression in wbl at 3 days postmarathon (decline of 40% vs. increase of 1000%; p < 0.05). In conclusion, physical stress affects circulating DCs, with an increase of myeloid and a decrease of plasmozytoid DCs. This may partially explain the susceptibility to viral infections after strenuous exercise. These detrimental effects are not attenuated by polyphenol supplementation. However, polyphenols support regeneration of viral antigen presenting TLR7 after strenuous exercise.

Exercise-induced biochemical changes and their potential influence on cancer: a scientific review

AIM

To review and discuss the available international literature regarding the indirect and direct biochemical mechanisms that occur after exercise, which could positively, or negatively, influence oncogenic pathways.

METHODS

The PubMed, MEDLINE, Embase and Cochrane libraries were searched for papers up to July 2016 addressing biochemical changes after exercise with a particular reference to cancer. The three authors independently assessed their appropriateness for inclusion in this review based on their scientific quality and relevance.

RESULTS

168 papers were selected and categorised into indirect and direct biochemical pathways. The indirect effects included changes in vitamin D, weight reduction, sunlight exposure and improved mood. The direct effects included insulin-like growth factor, epigenetic effects on gene expression and DNA repair, vasoactive intestinal peptide, oxidative stress and antioxidant pathways, heat shock proteins, testosterone, irisin, immunity, chronic inflammation and prostaglandins, energy metabolism and insulin resistance.

SUMMARY

Exercise is one of several lifestyle factors known to lower the risk of developing cancer and is associated with lower relapse rates and better survival. This review highlights the numerous biochemical processes, which explain these potential anticancer benefits.

Lack of desensitization of the cough reflex in ovalbumin-sensitized rabbits during exercise

Introduction

Cough is a major symptom of asthma frequently experienced during exercise but little is known about interactions between cough and exercise. The goal of our study was to clarify the potential modulation of the cough reflex (CR) by exercise in a spontaneously breathing anaesthetized animal model of airway eosinophilic inflammation.

Materials & methods

Ten ovalbumin (OVA) sensitized adult rabbits and 8 controls were studied. The ventilatory response to direct tracheal stimulation, performed both at rest and during exercise was determined to quantify the incidence and the sensitivity of the CR.

Broncho-alveolar lavages (BAL) and cell counts were performed to assess the level of the airway inflammation following OVA-induced sensitization. Exercise was mimicked by Electrically induced hindlimb Muscular Contractions (EMC).

Results

Among 494 tracheal stimulations, 261 were performed at rest and 233 at exercise. OVA challenges in sensitized rabbits caused a significant increase in the percentage of eosinophils (p = 0.008) in BAL. EMC increased minute ventilation by 36% and 35% in OVA and control rabbits respectively, compared to rest values. The sensitivity of the CR decreased during exercise compared to baseline in control rabbits (p = 0.0313) while it remained unchanged in OVA rabbits.

Conclusion

The desensitization of the CR during exercise in control rabbits was abolished in OVA rabbits. The precise role of airway inflammation in this lack of CR desensitization needs to be further investigated but it might contribute to the exercise-induced cough in asthmatics.

A randomized controlled trial examining the effects of 16 weeks of moderate-to-intensive cycling and honey supplementation on lymphocyte oxidative DNA damage and cytokine changes in male road cyclists

The aim of this study was to investigate whether honey supplementation (70g, ninety minutes before each training session) attenuates changes in lymphocyte counts, DNA damage, cytokines, antioxidative and peroxidative biomarkers following moderate-to-intensive exercise training in male road cyclists. Healthy nonprofessional cyclists (n=24, aged 17-26years) were randomly assigned to exercise+supplement (EX+S, n=12) and exercise (EX, n=12) groups for an experimental period of 16weeks. Moderate-to-intensive exercise training increased lymphocytes DNA damage, cytokines and peroxidative biomarkers as well as decreased antioxidative biomarkers in the EX group. These changes were significantly attenuated in the EX+S group. Furthermore, for both groups the observed changes in peroxidative and antioxidative biomarkers could be correlated positively and negatively, respectively, with lymphocyte DNA damage and cytokines. Findings suggest that honey attenuates oxidative stress and lymphocyte DNA damage after exercise, activities that are most likely attributable to its high antioxidant capacity.

The impact of sleeping with reduced glycogen stores on immunity and sleep in triathletes

PURPOSE

We investigated the effects of a 3-week dietary periodization on immunity and sleep in triathletes.

METHODS

21 triathletes were divided into two groups with different nutritional guidelines during a 3-week endurance training program including nine twice a day sessions with lowered (SL group) or maintained (CON group) glycogen availability during the overnight recovery period. In addition to performance tests, sleep was monitored every night. Systemic and mucosal immune parameters as well as the incidence of URTI were monitored every week of the training/nutrition protocol. Two-ways ANOVA and effect sizes were used to examine differences in dependent variables between groups at each time point.

RESULTS

The SL group significantly improved 10 km running performance (-1 min 13 s, P < 0.01, d = 0.38), whereas no improvement was recorded in the CON group (-2 s, NS). No significant changes in white blood cells counts, plasma cortisol and IL-6 were recorded over the protocol in both groups. The vitamin D status decreased in similar proportions between groups, whereas salivary IgA decreased in the SL group only (P < 0.05, d = 0.23). The incidence of URTI was not altered in both groups. All participants in both groups went to bed earlier during the training program (SL -20 min, CON -27 min, P < 0.05, d = 0.28). In the SL group, only sleep efficiency slightly decreased by 1.1 % (P < 0.05, d = 0.25) and the fragmentation index tended to increase at the end of the protocol (P = 0.06).

CONCLUSION

Sleeping and training the next morning regularly with reduced glycogen availability has minimal effects on selected markers of immunity, the incidence of URTI and sleeping patterns in trained athletes.

Blood immune function parameters in response to combined aerobic dance exercise and honey supplementation in adult women

To date, information on the effectiveness of combined aerobic dance exercise with honey supplementation on immune function in women is lacking. The present study investigated the effects of 8 weeks of combined aerobic dance exercise and honey supplementation on blood immune function parameters in adult women. In this study, forty four healthy sedentary women (25-40 year-old) were assigned into four groups with n = 11 per group: sedentary without supplementation control (Con), honey supplementation (H), aerobic dance exercise (D) and combined aerobic dance exercise with honey supplementation (HD) groups. Aerobic dance exercise was carried out for one hour per session, three sessions per week for eight weeks. Honey drink was consumed by H and HD groups, in a dosage of 20 g of honey diluted in 300 ml of plain water, consumed 7 days a week for 8 weeks. In HD group, the participants were required to consume honey drink 30 min before performing exercise. Before and after 8 weeks of experimental period, blood samples were taken to determine the concentrations of immune parameters which include full blood counts and immunophenotyping measurements. It was found that after 8 weeks of experimental period, there were statistically significant increases in T cytotoxic (CD8) (p < 0.05) in HD group. Additionally, the percentages increase in total lymphocyte counts, T helper (CD4), and T cytotoxic (CD8) counts after 8 weeks were the highest in HD group among all the groups. As conclusion, combined aerobic dance and honey supplementation may have potential to enhance immune functions in women.

Physical activity, sedentary behaviors, and Epstein-Barr virus antibodies in young adults

This study aimed to elucidate the associations between physical activity, sedentary behaviors, and Epstein-Barr virus (EBV) antibody levels (as an indirect marker of cell-mediated immunity, CMI). This study made use of a 14-year longitudinal study with a representative sample of adolescents in the US. A total of 3361 participants (42.1% male) aged 11 to 21years at baseline who completed Wave I (1994-1995), Wave III (2001-2002), and Wave IV (2008) surveys of the National Longitudinal Study of Adolescent Health (Add Health) were analyzed. Physical activity and sedentary behaviors at Waves I and III were assessed using interviewer-administered questionnaire. EBV viral capsid antigen (VCA) IgG antibody levels at Wave IV were analyzed from dried blood spot assays. Adjusted for confounders, among males, one additional day spent per week on strenuous sports at Wave III were associated with a decrease of 4.09AU/ml in EBV antibody levels (p=0.012), while one additional hour spent per week viewing videos at Wave I was associated with an increase of 0.83AU/ml in EBV antibody levels (p=0.026). Among females, one additional day spent per week on individual sports at Wave III were associated with a decrease of 4.63AU/ml in EBV antibody levels (p=0.014), while sedentary behaviors were not associated with EBV antibody levels. To conclude, physical activity and sedentary behaviors were associated with CMI among males and physical activity was associated with CMI among females.

Ecological Immunology through the Lens of Exercise Immunology: New Perspective on the Links between Physical Activity and Immune Function and Disease Susceptibility in Wild Animals

Locomotion and other physical activities by free-living animals may influence immune function and disease susceptibility. This influence may be a consequence of energetic trade-offs or other mechanisms that are often, but not always, inseparably linked to an animal's life history (e.g., flight and migration). Ecological immunology has mainly focused on these life-history trade-offs, overlooking the possible effects of physical activity per se on immune function and disease susceptibility. In this review, we explore the field of exercise immunology, which examines the impact of exercise on immune function and disease susceptibility in humans, with the aim of presenting new perspectives that might be transferable to ecological immunology. First, we explore key concepts in exercise immunology that could be extended to animals. Next, we investigate the concept "exercise" in animals, and propose the use of "physical activity" instead. We briefly discuss methods used in animals to quantify physical activity in terms of energy expenditure and summarize several examples of animals engaging in physical activity. Then, we highlight potential consequences of physical activity on immune function and disease susceptibility in animals, together with an overview of animal studies that examine these links. Finally, we explore and discuss the potential for incorporating perspectives from exercise immunology into ecological immunology. Such integration could help advance our understanding of human and animal health and contribute new ideas to budding "One Health" initiatives.

Can exercise affect the course of inflammatory bowel disease? Experimental and clinical evidence

The inflammatory bowel disease (IBD) consisting of Crohn's disease (CD) and ulcerative colitis (UC) are defined as idiopathic, chronic and relapsing intestinal disorders occurring in genetically predisposed individuals exposed to environmental risk factors such as diet and microbiome changes. Since conventional drug therapy is expensive and not fully efficient, there is a need for alternative remedies that can improve the outcome in patients suffering from IBD. Whether exercise, which has been proposed as adjunct therapy in IBD, can be beneficial in patients with IBD remains an intriguing question. In this review, we provide an overview of the effects of exercise on human IBD and experimental colitis in animal models that mimic human disease, although the information on exercise in human IBD are sparse and poorly understood. Moderate exercise can exert a beneficial ameliorating effect on IBD and improve the healing of experimental animal colitis due to the activity of protective myokines such as irisin released from working skeletal muscles. CD patients with higher levels of exercise were significantly less likely to develop active disease at six months. Moreover, voluntary exercise has been shown to exert a positive effect on IBD patients' mood, weight maintenance and osteoporosis. On the other hand, depending on its intensity and duration, exercise can evoke transient mild systemic inflammation and enhances pro-inflammatory cytokine release, thereby exacerbating the gastrointestinal symptoms. We discuss recent advances in the mechanism of voluntary and strenuous exercise affecting the outcome of IBD in patients and experimental animal models.

Cardiac Autonomic and Salivary Responses to a Repeated Training Bout in Elite Swimmers

This study examined the acute training responses of heart rate variability (HRV) and salivary biomarkers (immunoglobulin A and alpha-amylase) following a standardised training bout in Paralympic swimmers. Changes in HRV, sIgA and sAA were documented Monday morning, Monday afternoon and Tuesday morning over a 14-week monitoring period leading into international competition. Magnitude based inferences with effect sizes (ES) were used to assess the practical significance of changes each week. Normal training responses elicited increases in HR, α1, sAA and sIgA, accompanied by decreases in HF(nu), standard deviation of instantaneous RR variability (SD1) and the root mean square of successive differences (RMSSD) from Monday morning to Monday afternoon, and to Tuesday morning with similar week to week responses for most variables. Changes in RMSSD from Monday a.m. to p.m. were likely smaller (less negative) for Week 7 (78/18/3, ES = 0.40) following a competition weekend with similar changes observed from Monday a.m. to Tuesday a.m. (90/5/5, ES = 1.30). In contrast, the change in sAA from Monday a.m. to p.m. was very likely less (more negative) at Week 7 (0/0/99, ES = −2.46), with similar changes observed from Monday a.m. to Tuesday a.m. (0/0/99, ES = −4.69). During the taper period, there were also likely increases in parasympathetic modulations (RMSSD, Weeks 12–14) along with increased immune function (sIgA, Week 13) that demonstrated a favourable state of athlete preparedness. Used together, HRV and sAA provide coaches with valuable information regarding physiological changes in response to training and competition.

DESEMPENHO DE INDIVÍDUOS COM DERMOPIGMENTAÇÃO SUBMETIDOS À PRÁTICA DE EXERCÍCIO FÍSICO

RESUMO Introdução: A duração e a intensidade dos exercícios provocam diferentes alterações no sistema imunológico, dentre elas a diminuição das respostas imunes, acarretando queda no desempenho físico. Sabe-se também que a dermopigmentação pode colaborar com tais alterações no comportamento deste sistema. Objetivo: Avaliar os efeitos da dermopigmentação sobre o desempenho no exercício físico. Método: Neste ensaio clínico participaram 12 sujeitos, dentre eles seis com dermopigmentação, idade (anos), peso (Kg), estatura (cm) e gordura corporal (%) de 16,5 ± 1,16; 68,10 ± 6,83; 176,29 ± 7,71; 11,49 ± 0,58 respectivamente, divididos em dois grupos, sendo submetidos a teste de esforço máximo com intensidade progressiva em esteira ergométrica para determinação do consumo máximo de oxigênio (VO2máx), limiares anaeróbios (LAns) e economia de corrida (EC 14km/h %), sendo realizadas coletas de lactato pré e 5 minutos pós-teste. Os dados foram tratados por "teste t" para variáveis independentes, tendo como nível de significância adotado α < 0,05. Resultados: Foram observadas diferenças significativas entre os grupos em relação à concentração sanguínea de lactato (CSL) pré-teste (4,6 ± 0,11 e 3,23 ± 0,88 para dermopigmentados e não dermopigmentados, respectivamente; p < 0,05) e 5 minutos pós-teste (5,65 ± 0,49 e 13,13 ± 2,20 para dermopigmentados e não dermopigmentados, respectivamente; p < 0,05). O tempo de teste também foi significativamente superior para o grupo não dermopigmentado em comparação ao grupo com dermopigmentação (8 min 47 seg ± 0,08 e 7 min 39 seg ± 0,03 respectivamente; p < 0,05), bem como análise do WURSS-21 (3,33 ± 3,14 e 2,00 ± 1,09, respectivamente; p > 0,05). Em relação às demais variáveis dependentes (VO2máx, segundo limiar anaeróbio e economia de corrida) não foram encontradas diferenças estatisticamente significativas. Conclusão: A dermopigmentação produziu rendimento inferior no teste de esforço máximo, influenciando o desempenho no exercício físico.

Exercise and asthma: an overview

The terms 'exercise-induced asthma' (EIA) and 'exercise-induced bronchoconstriction' (EIB) are often used interchangeably to describe symptoms of asthma such as cough, wheeze, or dyspnoea provoked by vigorous physical activity. In this review, we refer to EIB as the bronchoconstrictive response and to EIA when bronchoconstriction is associated with asthma symptoms. EIB is a common occurrence for most of the asthmatic patients, but it also affects more than 10% of otherwise healthy individuals as shown by epidemiological studies. EIA and EIB have a high prevalence also in elite athletes, especially within endurance type of sports, and an athlete's asthma phenotype has been described. However, the occurrence in elite athletes shows that EIA/EIB, if correctly managed, may not impair physical activity and top sports performance. The pathogenic mechanisms of EIA/EIB classically involve both osmolar and vascular changes in the airways in addition to cooling of the airways with parasympathetic stimulation. Airways inflammation plays a fundamental role in EIA/EIB. Diagnosis and pharmacological management must be carefully performed, with particular consideration of current anti-doping regulations, when caring for athletes. Based on the demonstration that the inhaled asthma drugs do not improve performance in healthy athletes, the doping regulations are presently much less strict than previously. Some sports are at a higher asthma risk than others, probably due to a high environmental exposure while performing the sport, with swimming and chlorine exposure during swimming as one example. It is considered very important for the asthmatic child and adolescent to master EIA/EIB to be able to participate in physical activity on an equal level with their peers, and a precise early diagnosis with optimal treatment follow-up is vital in this aspect. In addition, surprising recent preliminary evidences offer new perspectives for moderate exercise as a potential therapeutic tool for asthmatics.