The leucocytosis of exercise. A review and model

Physiology and Pathophysiology of Marathon Running: A narrative Review

BACKGROUND

Marathon training and running have many beneficial effects on human health and physical fitness; however, they also pose risks. To date, no comprehensive review regarding both the benefits and risks of marathon running on different organ systems has been published.

MAIN BODY

The aim of this review was to provide a comprehensive review of the benefits and risks of marathon training and racing on different organ systems. A predefined search strategy including keywords (e.g., marathon, cardiovascular system, etc.) and free text search was used. Articles covering running regardless of sex, age, performance level, and event type (e.g., road races, mountain marathons) were considered, whereas articles examining only cycling, triathlon, stress-tests or other sports were excluded. In total, we found 1021 articles in PubMed, Scopus, and Google Scholar, of which 329 studies were included in this review. Overall, marathon training offers several benefits for different organ systems and reduces all-cause mortality. As such, it improves cardiovascular risk factors, leads to favorable cardiac adaptations, enhances lung function, and improves quality of life in chronic kidney disease patients. It also enhances gastrointestinal mobility and reduces the risk of specific tumors such as colorectal cancer and hepatocellular carcinoma. Marathon training enhances bone health and skeletal muscle metabolism. It further positively affects hematopoiesis and cytotoxic abilities of natural killer cells, and may act neuroprotective on a long-term basis. After a marathon, changes in biomarkers suggesting pathological events in certain organ systems such as cardiovascular, renal, gastrointestinal, liver, hematological, immune, musculoskeletal, central nervous, and endocrine systems can often be observed. Mostly, these changes are limited to 1-3 days post-race and usually normalize within a week. Moreover, marathon running poses the risk of serious adverse events such as sudden cardiac death or acute liver failure. Concerning lung function, a decrease after a marathon race was observed. Acute kidney injury, as well as electrolyte imbalances, are relatively common amongst marathon finishers. Many runners complain of gastrointestinal symptoms during or after long-distance running. Many runners suffer from running-related musculoskeletal injuries often impairing performance. A marathon is often accompanied by an acute inflammatory response with transient immunosuppression, making runners susceptible to infections. Also, hormonal alterations such as increased cortisol levels or decreased testosterone levels immediately after a race are observed. Disturbances in sleep patterns are commonly found in marathon runners leading up to or directly after the race.

CONCLUSION

All in all, marathon training is generally safe for human health and individual organ systems. Considering the high popularity of marathon running, these findings supply athletes, coaches, sports scientists, and sports medicine practitioners with practical applications. Further large-scale studies examining long-term effects on the cardiovascular, renal, and other system are needed.

An ultra-endurance event leads to changes in circulating regulatory T-cells, CD4+ naïve and CD8+ effector memory T-cells in the 48 h post-race recovery period

PURPOSE

Exercise is known to acutely affect T-lymphocyte populations in the peripheral blood, which is intensity- and duration-dependent. However, effects of longer duration endurance exercise (>5 h) on T-cells in the days following are unknown. The aim of this study was to investigate the circulating T-cell changes that occur in response to an ultra-endurance event, which may provide insight into the inflammatory response to ultra-endurance exercise.

METHODS

Ten individuals (m = 7, f = 3) completing an Ironman 70.3 event volunteered for the study. Peripheral blood samples were taken 1-2 days pre-race (PRE-RACE), and 1 day (RACE + 1) and 2 days (RACE + 2) post-race, with circulating T-cells enumerated by flow cytometry (total CD3+, CD4+ and CD8+ T-cells, regulatory T-cells [CD4+CD25+CD127-; TREG], naïve [CD27+CD45RA+; NA], central memory [CD27+CD45RA-; CM], effector memory [CD27-CD45RA-; EM], and effector memory CD45RA+ [CD27-CD45RA+; EMRA]).

RESULTS

There were no changes in total CD3+, CD4+ and CD8+ T-cells. TREG RACE + 1 was significantly higher compared to PRE-RACE, as were the proportion of CD4+ NA cells and CD8+ CM cells at RACE + 2; CD8+ EM cells fell at RACE + 2 (absolute counts and proportion).

CONCLUSION

In conclusion, the ultra-endurance event evoked T-cell changes over the 48 h recovery period, with an increase in T-cells that regulate the immune response, and a reduction in circulating EM T-cells, most likely trafficked to sites of tissue damage and inflammation.

The Impact of Acute Exercise on Blood Work Parameters: A Case Report of a Healthy Male University Student

This case report presents a 22-year-old male who exhibited critically high levels of creatine kinase (CK) (3,600 U/L), elevated liver transaminases (alanine aminotransferase (ALT) 90 U/L; aspartate aminotransferase (AST) 54 U/L), and elevated total bilirubin (30 µmol/L) following vigorous physical activity. The patient's blood work parameters normalized after a short period of exercise abstinence, highlighting the impact of acute exercise on blood work parameters and the importance of considering recent physical activity when interpreting laboratory results.

Acute Effects of Kickboxing K1 Matches on Hematological Parameters of Kickboxers

While there is clear evidence in the literature that the hematological parameters in athletes of different sports are affected by exercise and varying loads, to our knowledge, there are limited studies on the real impact of kickboxing matches on kickboxers' hematological parameters. In this context, this cross-sectional study was conducted to examine the acute changes in the hematological parameters of kickboxers following K1 matches. With the participation of 10 kickboxing K1 athletes, the hematological parameters, including the WBC, Plt, Neut, Lymph, Mono, RBC, Hgb, Hct, CK, La, and glucose levels, were examined before and after matches. Paired sample t-tests were used to compare the pre-test and post-test hematological parameters of the participants. The findings indicated statistically significant differences in the post-match WBC, Plt, Neut, Lymph, CK, La, and glucose levels, while no statistically significant differences were observed in the RBC, Hct, Hgb, and CK levels (p < 0.05). These results not only emphasize the complexity of physiological changes in athletes, but also show consistency with various findings in the literature, while contradicting some. Therefore, it is highlighted that further research is needed to understand the effects of K1 matches on hematological parameters.

The Influence of Exercise on Cancer Risk, the Tumor Microenvironment and the Treatment of Cancer

There are several modifiable factors that can be targeted to prevent and manage the occurrence and progression of cancer, and maintaining adequate exercise is a crucial one. Regular physical exercise has been shown to be a beneficial strategy in preventing cancer, potentially amplifying the effectiveness of established cancer therapies, alleviating certain cancer-related symptoms, and possibly mitigating side effects resulting from treatment. Nevertheless, the exact mechanisms by which exercise affects tumors, especially its impact on the tumor microenvironment (TME), remain uncertain. This review aims to present an overview of the beneficial effects of exercise in the context of cancer management, followed by a summary of the exercise parameters, especially exercise intensity, that need to be considered when prescribing exercise for cancer patients. Finally, we discuss the influence of exercise on the TME, including its effects on crucial immune cells (e.g., T cells, macrophages, neutrophils, natural killer cells, myeloid-derived suppressor cells, B cells), intratumor angiogenesis, and cancer metabolism. This comprehensive review provides up-to-date scientific evidence on the effects of exercise training on cancer and offers guidance to clinicians for the development of safe and feasible exercise training programs for cancer patients in clinical practice.

Immunology of Physical Exercise: Is Equus caballus an Appropriate Animal Model for Human Athletes?

Domestic horses routinely participate in vigorous and various athletic activities. This enables the horse to serve as a model for studying athletic physiology and immunology in other species, including humans. For instance, as a model of physical efforts, such as endurance rides (long-distance running/aerobic exercise) and races (anaerobic exercise), the horse can be useful in evaluating post-exercise response. Currently, there has been significant interest in finding biomarkers, which characterize the advancement of training and adaptation to physical exercise in the horse. The parallels in cellular responses to physical exercises, such as changes in receptor expression and blood cell activity, improve our understanding of the mechanisms involved in the body's response to intense physical activity. This study focuses on the changes in levels of the pro- and anti-inflammatory cytokines and cellular response in the context of post-exercise immune response. Both the direction of changes in cytokine levels and cellular responses of the body, such as proliferation and expression of surface markers on lymphocytes, monocytes and neutrophils, show cross-functional similarities. This review reveals that horses are robust research models for studying the immune response to physical exercise in human athletes.

Increase in Serum Interleukin-1 Receptor Antagonist (IL-1ra) Levels after Wheelchair Half Marathon Race in Male Athletes with Spinal Cord Injury

Exercise increases the serum level of interleukin-6 (IL-6), which in turn stimulates the production of various inflammatory cytokine antagonists, such as interleukin-1 receptor antagonist (IL-1ra). Individuals with cervical spinal cord injury (CSCI) are at high risk of inflammatory conditions. This study compared the effects of wheelchair half marathon on the immune system of male athletes with CSCI and those with thoracic/lumber spinal cord injury (SCI). Neutrophil count, IL-1ra, IL-6, and various endocrine parameters were measured before, immediately and 1 h after the race in five CSCI and six SCI who completed the wheelchair marathon race. The percentage of neutrophils was significantly higher in CSCI immediately and 1 h after the race, compared with the baseline, and significantly higher in SCI at 1 h after the race. IL-6 was significantly higher immediately and 1 h after the race in SCI, whereas no such changes were noted in IL-6 in CSCI. IL-1ra was significantly higher at 1 h after the race in both SCI and CSCI. The race was associated with an increase in IL-1ra in both CSCI and SCI. These findings suggest wheelchair half marathon race increases IL-1ra even under stable IL-6 status in male CSCI individuals, and that such post-race increase in IL-1ra is probably mediated through circulatory neutrophils.

The Effect of Moderate-Intensity Physical Exercise on Some Serum Inflammation Markers and the Immune System in Rats Fed Intermittent Fasting with a High-Fat Diet

Background and Objectives: This study aimed to investigate the impact of moderate-intensity physical exercise on serum inflammation markers and the immune system in rats that were fed a high-fat diet (HFD) with intermittent fasting. Materials and Methods: A total of 48 Wistar albino male rats were included in the study and divided into eight groups, each consisting of six rats. Group 1 served as the control group (CG), receiving a standard diet. Group 2 followed the standard nutrition program with intermittent fasting (CG + IF). Group 3 underwent exercise with a standard diet (CG + E). Group 4 underwent both a standard diet with intermittent fasting and exercise (CG + IF + E). Group 5 was fed a high-fat diet (HFD). Group 6 received a high-fat diet with intermittent fasting (HFD + IF). Group 7 followed a high-fat diet with exercise (HFD + E). Group 8 underwent both a high-fat diet with intermittent fasting and exercise (HFD + IF + E). The study lasted for 8 weeks. Results: The results of the analysis show that lymphocyte cell levels in groups HFD + IF, HFD + IF, and HFD + IF + E were higher compared to groups CG-HFD (p < 0.05). Additionally, B lymphocyte and monocyte cell levels were higher in group HFD + IF + E compared to groups CG, CG + IF, and CG + IF + E, as well as CG, CG + IF, and CG + E, respectively. TNF-α levels were significantly higher in group HFD compared to the other groups. Furthermore, IL 10 levels were higher in group HFD + IF + E compared to the other groups. Conclusions: These findings indicate that moderate exercise and intermittent fasting, particularly in groups fed a high-fat diet, increased anti-inflammatory cytokine levels, and certain immune system cell counts, while decreasing pro-inflammatory cytokine levels.

The Effect of Aerobic Exercise and Low-Impact Pilates Workout on the Adaptive Immune System

Growing evidence indicates the pronounced effects of physical activity on immune functions, which may largely depend on the type of exercise, intensity, and duration. However, limited information is available regarding the effects of low-impact exercises, especially on the level of adaptive immune system. Our study aimed to investigate and compare the changes in a broad spectrum of lymphocyte subtypes after 14 weeks of aerobic-type total-body-shaping workouts (TBSW) and Pilates workouts (PW) among healthy individuals. We determined the percentages of peripheral natural killer cells and different T and B lymphocyte subtypes with flow cytometry. At the end of the exercise program, significant changes in naïve and memory lymphocyte ratios were observed in TBSW group. Percentages of naïve cytotoxic T (Tc) cells elevated, frequencies of memory Tc and T-helper cell subsets decreased, and distribution of naïve and memory B cells rearranged. Proportions of activated T cells also showed significant changes. Nonetheless, percentages of anti-inflammatory interleukin (IL)-10-producing regulatory type 1 cells and immunosuppressive CD4⁺CD127^lo/-CD25^bright T regulative cells decreased not only after TBSW but also after PW. Although weekly performed aerobic workouts may have a more pronounced impact on the adaptive immune system than low-impact exercises, both still affect immune regulation in healthy individuals.

Hiding in plain sight? A review of post-convulsive leukocyte elevations

During physiological stress responses such as vigorous exercise, emotional states of fear and rage, and asphyxia, the nervous system induces a massive release of systemic catecholamines that prepares the body for survival by increasing cardiac output and redirecting blood flow from non-essential organs into the cardiopulmonary circulation. A curious byproduct of this vital response is a sudden, transient, and redistributive leukocytosis provoked mostly by the resultant shear forces exerted by rapid blood flow on marginated leukocytes. Generalized convulsive seizures, too, result in catecholamine surges accompanied by similar leukocytoses, the magnitude of which appears to be rooted in semiological factors such as convulsive duration and intensity. This manuscript reviews the history, kinetics, physiology, and clinical significance of post-convulsive leukocyte elevations and discusses their clinical utility, including a proposed role in the scientific investigation of sudden unexpected death in epilepsy (SUDEP).

Interlink Between Physiological and Biomechanical Changes in the Swim-to-Cycle Transition in Triathlon Events: A Narrative Review

Triathlon is a multisport composed of swim, cycle, and run segments and two transition periods. The swim-to-cycle transition is considered a critical period for the change in body position and the modifications in physiological (heart rate, VO₂, lactate) and biomechanical parameters (cycling power and cadence, swimming stroke rate). Therefore, the aim of this review was to summarize the current evidence regarding the physiological and biomechanical changes and their interlink during the swim-to-cycle transition hinting at practical recommendations for coaches and athletes. The influence of the swim segment on cycle one is more evident for short-distance events. Greater modifications occur in athletes of lower level. The modulation of intensity during the swim segment affects the changes in the physiological parameters (heart rate, blood lactate, core temperature), with a concomitant influence on cycling gross efficiency. However, gross efficiency could be preserved by wearing a wetsuit or by swimming in a drafting position. A higher swim leg frequency during the last meters of the segment induces a higher cadence during the cycle segment. Training should be directed to the maintenance of a swimming intensity around 80–90% of a previous maximal swim test and with the use of a positive pacing strategy. When athletes are intended to train consecutively only swim and cycle segments, for an optimal muscle activation during cycling, triathletes could adopt a lower cadence (about 60–70% of their typical cadence), although an optimal pedaling cadence depends on the level and type of athlete. Future research should be focused on the combined measurements of physiological and biomechanical parameters using an intervention study design to evaluate training adaptations on swim kick rate and their effects on cycling performance. Coaches and athletes could benefit from the understanding of the physiological and biomechanical changes occurring during the swim-to-cycle transition to optimize the overall triathlon performance.

Supply of Antioxidants vs. Recruit Firefighters' Cellular Immune Status: A Randomized Double-Blinded Placebo-Controlled Parallel-Group Trial

Background: Physical exercise can affect the immune system. We studied the effect of antioxidants on hematological and immune biomarkers after heavy training. Methods: 24 well-trained and well-fed male firefighters were randomly divided into supplemented and placebo groups, and tested for immunology-related variables using venous blood samples in the fasting state, pre- (M1) and post- (M2) five weeks of daily micronutrient supplementation (15 mg of beta-carotene, 200 mg of vitamin C, 136 mg of vitamin E, 200 μg of selenium, 15 mg of zinc, 100 mg of magnesium). Total leukocytes and a differential count for five populations were determined using standard procedures (MAXM—Beckman Coulter Diagnostics; Brea, CA, USA). Lymphocyte subsets were determined through immunophenotyping. Results: Although all values were within the normal range for healthy adults and athletes in the supplemented group (SG), mean CD3+CD8+, CD8+ and CD16+CD56+ decreased (p < 0.05; small to moderate effects), while mean CD4+, CD19+ and CD4+/CD8+ increased (p < 0.05; small effects) after five-weeks. Regarding the placebo group (PG), higher total leukocyte count (p < 0.05; trivial effect) and natural killer cells percentage (CD16+CD56+; p < 0.05; moderate effect) were observed when comparing M1 and M2. Conclusions: Antioxidants supplementation did not alter well-fed male firefighters recruit firefighters’ immune cell response during the five-week physical training program.

Evidence of immunometabolic dysregulation and airway dysbiosis in athletes susceptible to respiratory illness

Background

Methods

Findings

Interpretation

Funding

Basal Values of Biochemical and Hematological Parameters in Elite Athletes

The purpose of this study was to show how continuous exercise affects the basal values of biochemical and hematological parameters in elite athletes. A total of 14,010 samples (male = 8452 and female = 5558 (March 2011–March 2020)) from 3588 elite athletes (male = 2258 and female = 1330, mean age 24.9 ± 6.9 vs. 24.1 ± 5.5 years, respectively) from 32 sport modalities, were studied over 9 years to check the variation of basal biochemical and hematological parameter values. There were differences seen in the basal values of creatine kinase (CK), urea, creatinine, aspartate transaminase (AST), alanine aminotransferase (ALT), lactate dehydrogenase (LDH), potassium, total bilirubin, and eosinophil percentage compared to reference population data. However, other analytes showed narrow ranges of variation like glucose, total protein, albumin, sodium, hemoglobin, mean cell volume (MCV), and platelet count. Exercise produces changes in biochemical and hematological basal values of athletes compared to the general population, with the greatest variation in CK, but AST, ALT, LDH, potassium, and total bilirubin (TBil) show high values in serum, only with a wider distribution of values. The data here reflects the effect of exercise on biochemical and hematological parameter baseline ranges in elite athletes. As clinical laboratories use reference intervals to validate clinical reports, these “pseudo” reference intervals should be used when validating laboratory reports.

Polymorphonuclear leucocyte phagocytic function, γδ T-lymphocytes and testosterone as separate stress-responsive markers of prolonged, high-intensity training programs

Excessive exercise with limited recovery may lead to detrimental states of overreaching or the overtraining syndrome. Chronic maladaptation in endocrine and immune mechanisms occur with the incidence of these states. Exercise-induced cortisol and testosterone responses have been proposed as biomarkers of overreaching, with blunted responses following intensified-training periods. Yet, limited information on the effects of overreaching in immunity is available. Healthy individuals completed a 30-min running protocol (the RPE_TP) before and after a 12-day intensified-training period. Blood and saliva were collected before, after and 30min after RPE_TP at pre-training and post-training. Plasma and salivary cortisol and testosterone, leucocyte proliferation and polymorphonuclear leucocyte phagocytic activity were examined. Plasma and salivary cortisol were acutely unaffected pre-training (-14% and 0%, p ​> ​0.05) and post-training (-14% and +46%, p ​> ​0.05). Comparing pre-training with post-training, blunted responses were observed in plasma testosterone (43%-19%, p ​< ​0.05) and salivary testosterone (55%-24%, p ​> ​0.05). No acute or resting changes in total leucocyte counts or most leucocyte subsets occurred pre-training or post-training. Yet, a 194% acute elevation in γδ T-lymphocyte number occurred pre-training (p ​< ​0.05), and average resting concentrations were 174% higher post-training. Baseline phagocytic activity was 47% lower post-training (p ​< ​0.05). Intensified training was detrimental, significantly reducing phagocytic activity. Testosterone blunted post-training, indicating an excessive training-related hypothalamic-pituitary gonadal dysfunction. The γδ T-lymphocytes sensitivity to exercise was noted, rendering it as a potential stress-responsive cellular marker. The usefulness of the RPE_TP to track the onset of overreaching is proposed.

Overnight Immune Regulation and Subjective Measures of Sleep: A Three Night Observational Study in Adolescent Track and Field Athletes

To ensure health maintenance of young athletes, immunological stress due to physical exercise has to be balanced for performance development and health maintenance. Sleep is an important influencing factor for immune regulation because of its regenerating effect. In an attempt to assess overnight immune regulation, this observational study aimed to examine associations between changes in capillary immunological blood markers and measures of sleep in adolescent athletes. Over a period of three nights, 12 male (n = 6) and female (n = 6) adolescent track and field athletes aged 16.4 ± 1.1 years were monitored for their sleep behavior (e.g., sleep duration, sleep depth) and immune regulation by using subjective (e.g., sleep) and objective (capillary blood markers) measurement tools. Over the 4 day (three nights), athletes followed their daily routines (school, homework, free time activities, and training). Training was performed for different disciplines (sprint, hurdles, and long-jump) following their daily training routines. Training included dynamic core stability training, coordination training, speed training, resistance training, and endurance training. Capillary blood samples were taken 30-45 min after the last training session (10:00-12:00 a.m. or 5:00-6:00 p.m.) and every morning between 7:00 and 10:00 a.m. Changes in capillary blood markers from post-training to the next morning and morning-to-morning fluctuations in capillary blood markers were analyzed over a three-night period using a generalized estimating equations (GEE) statistical approach. Associations of overnight changes with measures of sleep were analyzed using GEE. We found significant decreases in white blood cell count (WBC), granulocytes (GRAN), granulocytes% (GRAN%), monocytes (MID), and granulocyte-lymphocyte-ratio. In contrast, lymphocytes% (LYM%) increased significantly and systemic inflammation index showed no difference from post-training to the next morning. Furthermore, there was a significant decrease in WBC and GRAN between morning 1 and morning 3. At morning 4, values returned to baseline (morning 1), irrespective if athletes performed a training session or rested on day 3. Furthermore, sleep duration was significantly and negatively associated with changes in WBC (βz = -0.491) and lymphocytes (βz = -0.451). Our results indicate that overnight sleep duration is an important parameter of immunological overnight regulation for adolescent athletes.

Quantitative Magnetic Resonance Imaging Assessment of the Quadriceps Changes during an Extreme Mountain Ultramarathon

INTRODUCTION/PURPOSE

Extreme ultra-endurance races are growing in popularity, but their effects on skeletal muscles remain mostly unexplored. This longitudinal study explores physiological changes in mountain ultramarathon athletes' quadriceps using quantitative magnetic resonance imaging (MRI) coupled with serological biomarkers. The study aimed to monitor the longitudinal effect of the race and recovery and to identify local inflammatory and metabolic muscle responses by codetection of biological markers.

METHODS

An automatic image processing framework was designed to extract imaging-based biomarkers from quantitative MRI acquisitions of the upper legs of 20 finishers at three time points. The longitudinal effect of the race was demonstrated by analyzing the image markers with dedicated biostatistical analysis.

RESULTS

Our framework allows for a reliable calculation of statistical data not only inside the whole quadriceps volume but also within each individual muscle head. Local changes in MRI parameters extracted from quantitative maps were described and found to be significantly correlated with principal serological biomarkers of interest. A decrease in the PDFF after the race and a stable paramagnetic susceptibility value were found. Pairwise post hoc tests suggested that the recovery process differs among the muscle heads.

CONCLUSIONS

This longitudinal study conducted during a prolonged and extreme mechanical stress showed that quantitative MRI-based markers of inflammation and metabolic response can detect local changes related to the prolonged exercise, with differentiated involvement of each head of the quadriceps muscle as expected in such eccentric load. Consistent and efficient extraction of the local biomarkers enables to highlight the interplay/interactions between blood and MRI biomarkers. This work indeed proposes an automatized analytic framework to tackle the time-consuming and mentally exhausting segmentation task of muscle heads in large multi-time-point cohorts.

Clozapine re-challenge and initiation following neutropenia: a review and case series of 14 patients in a high-secure forensic hospital

OBJECTIVE

Clozapine remains the most effective intervention for treatment resistant schizophrenia; however, its use is prohibited following neutropenias. We review neutrophil biology as applied to clozapine and describe the strategies to initiate clozapine following neutropenia used in a case series of 14 consecutive patients rechallenged in a United Kingdom (UK) high-secure psychiatric hospital. We examine outcomes including the use of seclusion and transfer.

METHODS

A case series of 14 male patients with treatment resistant schizophrenia treated with clozapine despite previous episodes of neutropenia between 2006 and 2015 is presented. Data were collected during 2015 and 2019. Using this routinely collected clinical data, we describe the patient characteristics, causes of neutropenia, the strategies used for rechallenging with clozapine and clinical outcomes.

RESULTS

Previous neutropenias were the result of benign ethnic neutropenia, clozapine, other medications and autoimmune-related. Our risk mitigation strategies included: granulocyte-colony stimulating factor (G-CSF), lithium and watch-and-wait. There were no serious adverse events; at follow up half of the patient's had improved sufficiently to transfer them to conditions of lesser security. There were dramatic reductions in the use of seclusion.

CONCLUSION

Even in this extreme group, clozapine can be safely and effectively re/initiated following neutropenias, resulting in marked benefits for patients. This requires careful planning based on an understanding of neutrophil biology and the aetiology of the specific episode of neutropenia.

Physical Activity and Natural Products and Minerals in the SARS-CoV-2 Pandemic: An Update

Coronavirus-disease 19 (COVID-19) has rapidly become a global public health issue, and there is a desperate need for strategies of prevention, reduction, and treatment to halt the epidemic. The coronavirus affects the immune system, and individuals with a compromised immune system, such as those with diabetes, hypertension, obesity, are more susceptible to this virus. Lifestyle-related variables such as physical activity and nutritional supplements can decrease inflammatory markers, increase anti-inflammatory and antioxidant status, and improve the immune system. Lifesty-lerelated variables play preventive roles against various infectious diseases including COVID-19. This review highlights the effects of physical activity and nutrients supplements on the immune system and their possible benefits in combating the harms caused by infection with the COVID-19 virus.

Muscle-Organ Crosstalk: Focus on Immunometabolism

Skeletal muscle secretes several hundred myokines that facilitate communication from muscle to other organs, such as, adipose tissue, pancreas, liver, gut, and brain. The biological roles of myokines include effects on e.g., memory and learning, as well as glucose and lipid metabolism. The present minireview focuses on recent developments showing that exercise-induced myokines are involved in immunometabolism of importance for the control of e.g., tumor growth and chronic inflammation. In this review, immunometabolism is discussed as the non-immune related pathologies leading to an immune response and some degree of inflammation, which promotes metabolic abnormalities.

Changes in γH2AX and H4K16ac levels are involved in the biochemical response to a competitive soccer match in adolescent players

The aim of this study was to examine novel putative markers of the response to the competitive soccer match in adolescent players, such as changes in global levels of γH2AX and H4K16ac in the chromatin of peripheral mononuclear blood cells (PMBCs) and a Fourier-transform infrared spectroscopy (FTIR)-based biochemical fingerprint of serum. These characteristics were examined with reference to the physiological and metabolic aspects of this response. Immediately post-match we noticed: (1) a systemic inflammatory response, manifesting as peaks in leukocyte count and changes in concentrations of IL-6, TNFα, and cortisol; (2) a peak in plasma lactate; (3) onset of oxidative stress, manifesting as a decline in GSH/GSSG; (4) onset of muscle injury, reflected in an increase in CK activity. Twenty-four hours post-match the decrease in GSH/GSSG was accompanied by accumulation of MDA and 8-OHdG, macromolecule oxidation end-products, and an increase in CK activity. No changes in SOD1 or GPX1 levels were found. Repeated measures correlation revealed several associations between the investigated biomarkers. The FTIR analysis revealed that the match had the greatest impact on serum lipid profile immediately post-game. In turn, increases in γH2AX and H4K16ac levels at 24 h post-match indicated activation of a DNA repair pathway.

Muscle-Organ Crosstalk: The Emerging Roles of Myokines

Physical activity decreases the risk of a network of diseases, and exercise may be prescribed as medicine for lifestyle-related disorders such as type 2 diabetes, dementia, cardiovascular diseases, and cancer. During the past couple of decades, it has been apparent that skeletal muscle works as an endocrine organ, which can produce and secrete hundreds of myokines that exert their effects in either autocrine, paracrine, or endocrine manners. Recent advances show that skeletal muscle produces myokines in response to exercise, which allow for crosstalk between the muscle and other organs, including brain, adipose tissue, bone, liver, gut, pancreas, vascular bed, and skin, as well as communication within the muscle itself. Although only few myokines have been allocated to a specific function in humans, it has been identified that the biological roles of myokines include effects on, for example, cognition, lipid and glucose metabolism, browning of white fat, bone formation, endothelial cell function, hypertrophy, skin structure, and tumor growth. This suggests that myokines may be useful biomarkers for monitoring exercise prescription for people with, for example, cancer, diabetes, or neurodegenerative diseases.

Potential Importance of Immune System Response to Exercise on Aging Muscle and Bone

PURPOSE OF REVIEW

The age-related loss of skeletal muscle and bone tissue decreases functionality and increases the risk for falls and injuries. One contributing factor of muscle and bone loss over time is chronic low-grade inflammation. Exercise training is an effective countermeasure for decreasing the loss of muscle and bone tissue, possibly by enhancing immune system response. Herein, we discuss key interactions between the immune system, muscle, and bone in relation to exercise perturbations, and we identify that there is substantial "cross-talk" between muscle and bone and the immune system in response to exercise.

RECENT FINDINGS

Recent advances in our understanding of the "cross-talk" between muscle and bone and the immune system indicate that exercise is likely to mediate many of the beneficial effects on muscle and bone via their interactions with the immune system. The age-related loss of muscle and bone tissue may be partially explained by an impaired immune system via chronic low-grade inflammation. Exercise training has a beneficial effect on immune system function and aging muscle and bone. Theoretically, the "cross-talk" between the immune system, muscle, and bone in response to exercise enhances aging musculoskeletal health.

The Influence of Floorball on Hematological Parameters: Consequences in Health Assessment and Antidoping Testing

Assessment of hematological parameters is common in sports medicine. Although physical exercise is an important preanalytical variable, data about acute hematological changes after high-intensity intermittent exercise are scarce. This study aimed to examine floorball as a potential preanalytical variable for hematological parameters used in health assessment and antidoping testing. Twenty-three professional male floorball players participated in a floorball game. Hematological parameters including hemoglobin, erythrocyte count and erythrocyte indices, reticulocytes, white blood cells (WBC), platelets, reticulocytes, and OFF-hr score were assessed at baseline, immediately postgame, and at 2 h postgame. Median hemoglobin concentration decreased significantly from 146 g/L pregame to 141 g/L immediately postgame (p < 0.001). WBC count increased from 7.2 × 10⁹/L pregame to 10.1 × 10⁹/L 2 h postgame (p < 0.001). The median OFF-hr score decreased from 99.5 to 94.2 immediately postgame and remained significantly lower than baseline at 2 h postgame (94.4, p=0.030). Looking at individual results, the highest OFF-hr score increased from 120 at baseline to 124 at 2 h postgame. Our findings suggest that participation in a floorball game affects several hematological parameters and consequently can affect health assessment and antidoping testing.

Clozapine rechallenge and initiation despite neutropenia- a practical, step-by-step guide

Clozapine remains the only drug treatment likely to benefit patients with treatment resistant schizophrenia. Its use is complicated by an increased risk of neutropenia and so there are stringent monitoring requirements and restrictions in those with previous neutropenia from any cause or from clozapine in particular. Despite these difficulties clozapine may yet be used following neutropenia, albeit with caution. Having had involvement with 14 cases of clozapine use in these circumstances we set out our approach to the assessment of risks and benefits, risk mitigation and monitoring with a practical guide.

Cellular immune response to acute exercise: Comparison of endurance and resistance exercise

OBJECTIVES

Exercise-induced cellular mobilization might play a role in treatment and prevention of several diseases. However, little is known about the impact of different exercise modalities on immune cell mobilization and clinical cellular inflammation markers. Therefore, the present study aimed to investigate differences between acute endurance exercise (EE) and resistance exercise (RE) on cellular immune alterations.

METHODS

Twenty-four healthy men conducted an acute EE (cycling at 60% of peak power output) and RE (five exercise machines at 70% of the one-repetition maximum) session lasting 50 minutes in randomized order. Blood samples were collected before, after and one hour after exercise cessation. Outcomes included counts and proportions of leukocytes, neutrophils (NEUT), lymphocytes (LYM), LYM subsets, CD4/CD8 ratio, and the clinical cellular inflammation markers NEUT/LYM ratio (NLR), platelets/LYM ratio (PLR), and systemic immune inflammation index (SII).

RESULTS

Alterations in all outcomes were revealed except for CD8⁺ T cells, CD4/CD8 ratio, NLR, and PLR. EE induced a stronger cellular immune response and provoked alterations in more immune cell populations than RE. SII was altered only after EE.

CONCLUSION

An acute EE session causes a stronger mobilization of immune cells than RE. Additionally, SII represents an integrative marker to depict immunological alterations.

Effect of Acute and Chronic Aerobic Exercise on Immunological Markers: A Systematic Review

Introduction: The effects of aerobic exercise on the immune system are not yet fully defined in the scientific literature. This fact demonstrates the need to investigate its influence on existing immunological markers by classifying and quantifying their acute and chronic effects. Objective: To investigate the effects of acute and chronic aerobic exercise on inflammatory markers of healthy adults. Methods: This study is a systematic review according to PRISMA recommendations. The following databases were searched: MEDLINE (via PubMed), Science Direct, Scopus, Web of Science, SciELO, Bireme and Cochrane Library, and article references. The last search was performed in March 2019. We included randomized controlled trials (RCTs) and non-randomized controlled trials (NRCTs) investigating the acute and chronic effects of aerobic exercise on immune markers in healthy male and female adults aged 20 to 45 years, without restrictions in language or year of publication. Two authors independently analyzed the studies by reading the titles, abstracts, and full texts. Risk of Study bias was analyzed using Cochrane's Risk of Bias Tool. Outcomes: We included 15 studies in this systematic review, 13 of which were acute intervention and 2 were chronic, with 296 participants, 196 men and 100 women all being healthy individuals. It was observed that the acute intervention promotes changes in most immunological markers, while the chronic intervention interferes with a smaller proportion, this being in lymphocyte subpopulations. In the evaluation of quality, it was found that most studies did not present a high risk of bias in the evaluated aspects, but an unclear related risk of bias was observed, requiring a more careful analysis. Conclusion: Thus, it can be concluded that the evidence indicates that acute and chronic interventions may modify most immune markers, but aspects such as gender, contraceptive pill use in women, physical capacity of the investigated individuals, environment, and type and intensity of the exercises may interfere with these markers as well as the data analysis. Therefore, this review suggests that further research is needed to contribute to the confirmation and estimation of results.

Exercise Regulates the Immune System

The profound effect of exercise on the normal functioning of the immune system has been well-known. Exercise and immune regulation are interrelated and affect each other. Exercise changes immune regulation by affecting leucocytes, red blood cells, and cytokines, etc. Regular exercise could reduce the risk of chronic metabolic and cardiorespiratory diseases, partially by the anti-inflammatory effects of exercise. However, these effects are also likely to be responsible for the suppressed immunity that make our bodies more susceptible to infections. Here we summarize the known mechanisms by which exercise-both acute and chronic-exerts its immune regulation effects.

The role of glucose homeostasis on immune function in response to exercise: The impact of low or higher energetic conditions

Immune cells are bioenergetically expensive during activation, which requires tightly regulated control of metabolic pathways. Both low and high glycemic conditions can modulate immune function. States of undernourishment depress the immune system, and in the same way, excessive intake of nutrients, such as an obesity state, compromise its functioning. Multicellular organisms depend on two mechanisms to survive: the regulation and ability to store energy to prevent starvation and the ability to fight against infection. Synergic interactions between metabolism and immunity affect many systems underpinning human health. In a chronic way, the breakdown of glycemic homeostasis in the body can influence cells of the immune system and consequently contribute to the onset of diseases such as type II diabetes, obesity, Alzheimer's, and fat and lean mass loss. On the contrary, exercise, recognized as a primary strategy to control hyperglycemic disorders, also induces a coordinated immune-neuro-endocrine response that acutely modulates cardiovascular, respiratory, and muscle functions and the immune response to exercise is widely dependent on the intensity and volume that may affect an immunodepressive state. These altered immune responses induced by exercise are modulated through the "stress hormones" adrenaline and cortisol, which are a threat to leukocyte metabolism. In this context, carbohydrates appear to have a positive acute response as a strategy to prevent depression of the immune system by maintaining plasma glucose concentrations to meet the energy demand from all systems involved during strenuous exercises. Therefore, herein, we discuss the mechanisms through which exercise may promotes changes on glycemic homeostasis in the metabolism and how it affects immune cell functions under higher or lower glucose conditions.

Vitamin B6 improves blood parameters in rats fed a protein-deficient diet and subjected to moderate, long-term exercise

Vitamin B₆ is necessary for many enzymatic pathways (glucose and lipid metabolism, DNA/RNA synthesis, or modulation of gene expression) and affects immune cell function and blood-forming processes. We hypothesised that supplementing a protein-deficient diet with vitamin B₆ may reduce the negative impact of protein malnutrition. Here, we evaluated the effect of moderate, long-term exercise (ninety days) on selected blood parameters in rats fed a normal diet, a protein-deficient diet, or a protein-deficient diet supplemented with vitamin B₆. Selected haematological, immunological, and biochemical parameters were examined. A protein-deficient diet lasting 90 days caused significant reduction in body mass, increased activity of aminotransferases (asparagine and alanine), an increased percentage of innate cells in the blood, and decreased haemoglobin concentration in the blood. Adding vitamin B₆ significantly increased body and muscle mass, decreased liver parameters, and caused normalisation of haemoglobin concentration and the proportion of white blood cells in the blood. These results indicate that vitamin B₆ supplementation significantly improves the health of protein-malnourished rats and paves the way for the development of novel anti-malnutrition therapies.

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.

Modulation of exercise-induced muscular damage and hyperalgesia by different 630 nm doses of light-emitting diode therapy (LEDT) in rats

We compared the acute effects of different doses of 630 nm light-emitting diode therapy (LEDT) on skeletal muscle inflammation and hyperalgesia in rats submitted to exercise-induced muscle damage (EIMD). Wistar rats were divided into five experimental groups (n = 5-8/group): sedentary control (CON); exercise + passive recovery (PR); and exercise + LEDT (1.2 J/cm², 1.8 J; 4.2 J/cm², 6.3 J; 10.0 J/cm², 15 J). After 100 min of swimming, the rats in the LEDT groups were exposed to phototherapy on the triceps surae muscle. For mechanical hyperalgesia evaluation, paw withdrawal threshold was assessed before and 24 h after swimming. Immediately after hyperalgesia tests, blood samples were collected to analyze creatine kinase (CK) activity and the soleus muscle was removed for histological and tumor necrosis factor (TNF)-α immunohistological analyses. In all LEDT groups, plasma CK activity was reduced to levels similar to those measured in the CON group. Paw withdrawal threshold decreased in the PR group (- 11.9 ± 1.9 g) when compared to the CON group (2.2 ± 1.5 g; p < 0.01) and it was attenuated in the group LEDT 4.2 J/cm² (- 3.3 ± 2.4 g, p < 0.05). Less leukocyte infiltration and edema and fewer necrotic areas were found in histological sections of soleus muscle in LEDT (4.2 J/cm²) and LEDT (10.0 J/cm²) groups compared to the PR group. Also, LEDT (4.2 J/cm²) and LEDT (10.0 J/cm²) groups showed less immunostaining for TNF-α in macrophages or areas with necrosis of muscle fibers compared to the PR group. LEDT (4.2 J/cm², 6.3 J)-reduced muscle inflammation and nociception in animals submitted to EIMD.

Effects of Acute and Chronic Exercise on Immunological Parameters in the Elderly Aged: Can Physical Activity Counteract the Effects of Aging?

Immunosenescence is characterized by deterioration of the immune system caused by aging which induces changes to innate and adaptive immunity. Immunosenescence affects function and phenotype of immune cells, such as expression and function of receptors for immune cells which contributes to loss of immune function (chemotaxis, intracellular killing). Moreover, these alterations decrease the response to pathogens, which leads to several age-related diseases including cardiovascular disease, Alzheimer's disease, and diabetes in older individuals. Furthermore, increased risk of autoimmune disease and chronic infection is increased with an aging immune system, which is characterized by a pro-inflammatory environment, ultimately leading to accelerated biological aging. During the last century, sedentarism rose dramatically, with a concomitant increase in certain type of cancers (such as breast cancer, colon, or prostate cancer), and autoimmune disease. Numerous studies on physical activity and immunity, with focus on special populations (i.e., people with diabetes, HIV patients) demonstrate that chronic exercise enhances immunity. However, the majority of previous work has focused on either a pathological population or healthy young adults whilst research in elderly populations is scarce. Research conducted to date has primarily focused on aerobic and resistance exercise training and its effect on immunity. This review focuses on the potential for exercise training to affect the aging immune system. The concept is that some lifestyle strategies such as high-intensity exercise training may prevent disease through the attenuation of immunosenescence. In this context, we take a top-down approach and review the effect of exercise and training on immunological parameters in elderly at rest and during exercise in humans, and how they respond to different modes of training. We highlight the impact of these different exercise modes on immunological parameters, such as cytokine and lymphocyte concentration in elderly individuals.

Standardized Assessment of Resistance Training-Induced Subjective Symptoms and Objective Signs of Immunological Stress Responses in Young Athletes

From a health and performance-related perspective, it is crucial to evaluate subjective symptoms and objective signs of acute training-induced immunological responses in young athletes. The limited number of available studies focused on immunological adaptations following aerobic training. Hardly any studies have been conducted on resistance-training induced stress responses. Therefore, the aim of this observational study was to investigate subjective symptoms and objective signs of immunological stress responses following resistance training in young athletes. Fourteen (7 females and 7 males) track and field athletes with a mean age of 16.4 years and without any symptoms of upper or lower respiratory tract infections participated in this study. Over a period of 7 days, subjective symptoms using the Acute Recovery and Stress Scale (ARSS) and objective signs of immunological responses using capillary blood markers were taken each morning and after the last training session. Differences between morning and evening sessions and associations between subjective and objective parameters were analyzed using generalized estimating equations (GEE). In post hoc analyses, daily change-scores of the ARSS dimensions were compared between participants and revealed specific changes in objective capillary blood samples. In the GEE models, recovery (ARSS) was characterized by a significant decrease while stress (ARSS) showed a significant increase between morning and evening-training sessions. A concomitant increase in white blood cell count (WBC), granulocytes (GRAN) and percentage shares of granulocytes (GRAN_%) was found between morning and evening sessions. Of note, percentage shares of lymphocytes (LYM_%) showed a significant decrease. Furthermore, using multivariate regression analyses, we identified that recovery was significantly associated with LYM_%, while stress was significantly associated with WBC and GRAN_%. Post hoc analyses revealed significantly larger increases in participants’ stress dimensions who showed increases in GRAN_%. For recovery, significantly larger decreases were found in participants with decreases in LYM_% during recovery. More specifically, daily change-scores of the recovery and stress dimensions of the ARSS were associated with specific changes in objective immunological markers (GRAN_%, LYM_%) between morning and evening-training sessions. Our results indicate that changes of subjective symptoms of recovery and stress dimensions using the ARSS were associated with specific changes in objectively measured immunological markers.

Comparable Neutrophil Responses for Arm and Intensity-matched Leg Exercise

INTRODUCTION

Arm exercise is performed at lower absolute intensities than lower body exercise. This may impact on intensity-dependent neutrophil responses, and it is unknown whether individuals restricted to arm exercise experience the same changes in the neutrophil response as found for lower body exercise. Therefore, we aimed to investigate the importance of exercise modality and relative exercise intensity on the neutrophil response.

METHODS

Twelve moderately trained men performed three 45-min constant load exercise trials after determination of peak oxygen uptake for arm exercise (V˙O2peak arms) and cycling (V˙O2peak legs): 1) arm cranking exercise at 60% V˙O2peak arms, 2) moderate cycling at 60% V˙O2peak legs, and 3) easy cycling at 60% V˙O2peak arms.

RESULTS

Neutrophil numbers in the circulation increased for all exercise trials, but were significantly lower for easy cycling when compared with arm exercise (P = 0.009), mirroring the blunted increase in HR and epinephrine during easy cycling. For all trials, exercising HR explained some of the variation of the neutrophil number 2 h postexercise (R = 0.51-0.69), epinephrine explaining less of this variation (R = 0.21-0.34). The number of neutrophils expressing CXCR2 decreased in the recovery from exercise in all trials (P < 0.05).

CONCLUSIONS

Arm and leg exercise elicits the same neutrophil response when performed at the same relative intensity, implying that populations restricted to arm exercise might achieve a similar exercise induced neutrophil response as those performing lower body exercise. A likely explanation for this is the higher sympathetic activation and cardiac output for arm and relative intensity-matched leg exercise when compared with easy cycling, which is partly reflected in HR. This study further shows that the downregulation of CXCR2 may be implicated in exercise-induced neutrophilia.

Physical activity and autoimmune diseases: Get moving and manage the disease

Physical activity, by definition, is any skeletal muscle body movement that results in energy expenditure. In the last few decades, a plethora of scientific evidences have accumulated and confirmed the beneficial role of physical activity as a modifiable risk factor for a wide variety of chronic diseases including cardiovascular diseases (CVDs), diabetes mellitus and cancer, among others. Autoimmune diseases are a heterogeneous group of chronic diseases, which occur secondary to loss of self-antigen tolerance. With the advent of biological therapies, better outcomes have recently been noted in the management of autoimmune diseases. Nonetheless, recent research highlights the salient role of modifiable behaviors such as physical inactivity on various aspects of the immune system and autoimmune diseases. Physical activity leads to a significant elevation in T-regulatory cells, decreased immunoglobulin secretion and produces a shift in the Th1/Th2 balance to a decreased Th1 cell production. Moreover, physical activity has been proven to promote the release of IL-6 from muscles. IL-6 released from muscles functions as a myokine and has been shown to induce an anti-inflammatory response through IL-10 secretion and IL-1β inhibition. Physical activity has been shown to be safe in most of autoimmune diseases including systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), multiple sclerosis (MS), inflammatory bowel diseases (IBD), as well as others. Additionally, the incidence of RA, MS, IBD and psoriasis has been found to be higher in patients less engaged in physical activity. As a general trend, patients with autoimmune diseases tend to be less physically active as compared to the general population. Physically active RA patients were found to have a milder disease course, better cardiovascular disease (CVD) profile, and improved joint mobility. Physical activity decreases fatigue, enhances mood, cognitive abilities and mobility in patients with MS. In SLE patients, enhanced quality of life and better CVD profile were documented in more physically active patients. Physically active patients with type 1 diabetes mellitus have a decreased risk of autonomic neuropathy and CVD. Both fibromyalgia and systemic sclerosis patients report decreased disease severity, pain, as well as better quality of life with more physical activity. Further, SSc patients improve their grip strength, finger stretching and mouth opening with increased level of exercise. The purpose of this paper is to review the clinical evidence regarding the safety, barriers to engagement, and impact of physical activity on autoimmune diseases.

A systems biology approach to investigating the influence of exercise and fitness on the composition of leukocytes in peripheral blood

BACKGROUND

Exercise immunology has become a growing field in the past 20 years, with an emphasis on understanding how different forms of exercise affect immune function. Mechanistic studies are beginning to shed light on how exercise may impair the development of cancer or be used to augment cancer treatment. The beneficial effects of exercise on the immune system may be exploited to improve patient responses to cancer immunotherapy.

METHODS

We investigated the effects of acute exercise on the composition of peripheral blood leukocytes over time in a male population of varying fitness. Subjects performed a brief maximal intensity cycling regimen and a longer less intense cycling regimen at separate visits. Leukocytes were measured by multi-parameter flow cytometry of more than 50 immunophenotypes for each collection sample.

RESULTS

We found a differential induction of leukocytosis dependent on exercise intensity and duration. Cytotoxic natural killer cells demonstrated the greatest increase (average of 5.6 fold) immediately post-maximal exercise whereas CD15⁺ granulocytes demonstrated the largest increase at 3 h post-maximal exercise (1.6 fold). The longer, less intense endurance exercise resulted in an attenuated leukocytosis. Induction of leukocytosis did not differ in our limited study of active (n = 10) and sedentary (n = 5) subjects to exercise although we found that in baseline samples, sedentary individuals had elevated percentages of CD45RO⁺ memory CD4⁺ T cells and elevated proportions of CD4⁺ T cells expressing the negative immune regulator programmed death-1 (PD-1). Finally, we identified several leukocytes whose presence correlated with obesity related fitness parameters.

CONCLUSIONS

Our data suggests that leukocytes subsets are differentially mobilized into the peripheral blood and dependent on the intensity and duration of exercise. Pre-existing compositional differences of leukocytes were associated with various fitness parameters.

Effects of acute and chronic exercise on the osmotic stability of erythrocyte membrane of competitive swimmers

This study aimed to evaluate the influence of acute and chronic exercise on erythrocyte membrane stability and various blood indices in a population consisting of five national-level male swimmers, over 18 weeks of training. The evaluations were made at the beginning and end of the 1st, 7th, 13th and 18th weeks, when volume and training intensity have changed. The effects manifested at the beginning of those weeks were considered due to chronic adaptations, while the effects observed at the end of the weeks were considered due to acute manifestations of the exercise load of that week. Acute changes resulting from the exercise comprised increases in creatine kinase activity (CK) and leukocyte count (Leu), and decrease in hematocrit (Ht) and mean corpuscular volume (MCV), at the end of the first week; increase in the activities of CK and lactate dehydrogenase (LDH), in the uric acid (UA) concentration and Leu count, at the end of the seventh week; increases in CK and LDH activities and in the mean corpuscular hemoglobin concentration (MCHC), at the end of the 13th week; and decrease in the value of the osmotic stability index 1/H₅₀ and increases in the CK activity and platelets (Plt) count, at the end of the 18th week. Chronic changes due to training comprised increase in the values of 1/H₅₀, CK, LDH, high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), serum iron (Fe), MCV and Plt. Although acute training has resulted in decrease in the osmotic stability of erythrocytes, possibly associated with exacerbation of the oxidative processes during intense exercise, chronic training over 18 weeks resulted in increased osmotic stability of erythrocytes, possibly by modulation in the membrane cholesterol content by low and high density lipoproteins.

T-cell redeployment and intracellular cytokine expression following exercise: effects of exercise intensity and cytomegalovirus infection

The magnitude of lymphocytosis following exercise is directly related to exercise intensity. Infection with cytomegalovirus (CMV) also augments lymphocytosis after exercise. It is not known if the enhanced T-cell response to exercise due to CMV depends on exercise intensity. Furthermore, exercise-induced changes in T-cell expression of type I and type II cytokines are thought to be intensity dependent, but direct comparisons are lacking. The aim of this experiment was to determine if CMV affects the exercise-induced redistribution of T-cell subsets at varying intensities, and determine the effect of exercise intensity on CD8⁺ T-cell cytokine expression. Seventeen cyclists (nine CMV seropositive; CMV+) completed three 30 min cycling trials at -5, +5, and +15% of blood lactate threshold (LT). T-cell subsets in blood and intracellular expression of type I (IL-2, interferon(IFN)-γ) and type II (IL-4, IL-10) cytokines by CD8⁺ T cells pre, post, and 1-h post-exercise were assessed by flow cytometry. Independently of CMV, T-cell subset redistribution was greater after +15%LT compared to -5%LT (P < 0.05). Independently of intensity, CMV- mobilized more low- (CD27⁺ CD28⁺) and medium- (CD27⁺ CD28^-) differentiated T cells than CMV+, whereas CMV+ mobilized more high (CD27^- CD28^-) differentiated T cells. The numbers of IL-2+, IFN-γ+, IL-4+, and IL-10+ CD8⁺ T cells increased after exercise above LT Only type I cytokine expression was influenced by exercise intensity (P < 0.05). In conclusion, T-cell redeployment by exercise is directly related to exercise intensity, as are changes in the number of CD8⁺ T-cells expressing type I cytokines. Although CMV+ mobilized more high-differentiated T cells than CMV-, this occurred at all intensities. Therefore, the augmenting effect of CMV on T-cell mobilization is independent of exercise intensity.

Profiling of exercise-induced transcripts in the peripheral blood cells of Thoroughbred horses

Transcriptome analyses based on DNA microarray technology have been used to investigate gene expression profiles in horses. In this study, we aimed to identify exercise-induced changes in the expression profiles of genes in the peripheral blood of Thoroughbred horses using DNA microarray technology (15,429 genes on 43,603 probes). Blood samples from the jugular vein were collected from six horses before and 1 min, 4 hr, and 24 hr after all-out running on a treadmill. After the normalization of microarray data, a total of 26,830 probes were clustered into four groups and 11 subgroups showing similar expression changes based on k-mean clustering. The expression level of inflammation-related genes, including interleukin-1 receptor type II (IL-1R2), matrix metallopeptidase 8 (MMP8), protein S100-A8 (S100-A8), and serum amyloid A (SAA), increased at 4 hr after exercise, whereas that of c-Fos (FOS) increased at 1 min after exercise. These results indicated that the inflammatory response increased in the peripheral blood cells after exercise. Our study also revealed the presence of genes that may not be affected by all-out exercise. In conclusion, transcriptome analysis of peripheral blood cells could be used to monitor physiological changes induced by various external stress factors, including exercise, in Thoroughbred racehorses.

Shear-Wave Elastography Assessments of Quadriceps Stiffness Changes prior to, during and after Prolonged Exercise: A Longitudinal Study during an Extreme Mountain Ultra-Marathon

In sports medicine, there is increasing interest in quantifying the elastic properties of skeletal muscle, especially during extreme muscular stimulation, to improve our understanding of the impact of alterations in skeletal muscle stiffness on resulting pain or injuries, as well as the mechanisms underlying the relationships between these parameters. Our main objective was to determine whether real-time shear-wave elastography (SWE) can monitor changes in quadriceps muscle elasticity during an extreme mountain ultra-marathon, a powerful mechanical stress model. Our study involved 50 volunteers participating in an extreme mountain marathon (distance: 330 km, elevation: +24,000 m). Quantitative SWE velocity and shear modulus measurements were performed in most superficial quadriceps muscle heads at the following 4 time points: before the race, halfway through the race, upon finishing the race and after recovery (+48 h). Blood biomarker levels were also measured. A significant decrease in the quadriceps shear modulus was observed upon finishing the race (3.31±0.61 kPa) (p<0.001) compared to baseline (3.56±0.63 kPa), followed by a partial recovery +48 h after the race (3.45±0.6 kPa) (p = 0.002) across all muscle heads, as well as for each of the following three muscle heads: the rectus femoris (p = 0.003), the vastus medialis (p = 0.033) and the vastus lateralis (p = 0.001). Our study is the first to assess changes in muscle stiffness during prolonged extreme physical endurance exercises based on shear modulus measurements using non-invasive SWE. We concluded that decreases in stiffness, which may have resulted from quadriceps overuse in the setting of supra-physiological stress caused by the extreme distance and unique elevation of the race, may have been responsible for the development of inflammation and muscle swelling. SWE may hence represent a promising tool for monitoring physiologic or pathological variations in muscle stiffness and may be useful for diagnosing and monitoring muscle changes.

Acute bouts of exercise induce a suppressive effect on lymphocyte proliferation in human subjects: A meta-analysis

OBJECTIVE

Lymphocyte proliferative responses are commonly used to assess immune function in clinical settings, yet it is unclear how proliferative capacity is altered by exercise. This analysis aims to quantitatively assess the proliferative response of lymphocytes following an acute bout of exercise.

METHODS

Electronic databases were searched for articles containing the keywords "exercise" OR "acute" OR "aerobic" OR "resistance training" OR "immune function" AND "proliferation" AND "lymphocyte." Initial results yielded 517 articles of which 117 were reviewed in full. Twenty-four articles met the inclusion criteria. Calculated standardized mean difference (SMD) and corresponding standard errors (SE) were integrated using random-effect models.

RESULTS

Analyses uncovered evidence for suppression of proliferative capacity following acute exercise in general (SMD=-0.18, 95% CI: -0.21, -0.16) with long duration, high intensity exercise exhibiting a moderate suppressive effect (SMD=-0.55, 95% CI: -0.86, -0.24). Discordant proliferative responses for long duration, high intensity exercise in competitive versus non-competitive settings were identified with enhanced proliferation (SMD=0.46, 95% CI: 0.03, 0.89) observed following competitive events and a large suppressive effect detected for similar activities outside of a competitive environment (SMD: -1.28, 95% CI: -1.61, -0.96) (p=0.02).

CONCLUSION

Evidence suggests lymphocyte proliferation is suppressed following acute bouts of exercise, with exercise lasting longer than one hour having a greater magnitude of effect regardless of exercise intensity. Variations in observed effect sizes across intensity, duration, and competitive environment further highlight our need to acknowledge the impact of study designs in advancing our understanding of exercise immunology.

Effects of acute exercise on monocyte subpopulations in metabolic syndrome patients

OBJECTIVE

Acute exercise induces numerous changes in peripheral blood, e.g. counts of leukocytes. CD16^pos monocytes, which play a role in the pathogenesis of arteriosclerosis and the metabolic syndrome (MetS), are among the blood cells with the highest fold increase through exercise. So far no studies have investigated the effect of exercise on the blood cell composition of patients with MetS.

APPROACH AND RESULTS

Blood cell counts, a wide panel of laboratory tests, as well as lipid and protein content of monocytes and granulocytes were determined in healthy subjects, persons with metabolic risk and MetS patients before and after one minute of exercise at 400 W. Leukocyte counts increased significantly in all groups with CD14^pos CD16^pos monocytes showing the highest fold-change. In MetS patients the fold increase was smaller. They had a higher resting level of CD14^pos CD16^pos monocytes and a lower basal ratio of CD16^neg /CD16^pos monocytes. A similar ratio of these cells was induced in control and risk subjects after exercise. However, absolute counts of mobilized pro-inflammatory monocytes did not differ significantly. Furthermore, we detected a decrease in protein content of monocytes in controls, but not in MetS patients.

CONCLUSIONS

As strenuous exercise is able to mobilize the same amount of pro-inflammatory monocytes in MetS patients as in healthy persons, the elevated basal level of these cells in MetS patients is likely to be caused by enhanced maturation rather than chronic mobilization. The removal of these monocytes from the endothelium might be part of the beneficial effect of exercise on vascular disease. © 2016 International Clinical Cytometry Society.