Complement and immunoglobulin levels in athletes and sedentary controls

Heart Rate Variability and Cortisol Levels Before and After a Brief Anaerobic Exercise in Handball Players

ABSTRACT

Kayacan, Y, Makaracı, Y, Ucar, C, Amonette, WE, and Yıldız, S. Heart rate variability and cortisol levels before and after a brief anaerobic exercise in handball players. J Strength Cond Res 37(7): 1479-1485, 2023-Evaluating stress in athletes is important for monitoring overall physiologic load and is a core practice for sport performance teams. This study examined relationships between 2 metrics of training stress, heart rate variability (HRV) and cortisol, before and after intense anaerobic power testing. Electrocardiogram recordings and saliva samples were collected before and immediately after a Wingate anaerobic power test (WAnT-30) from professional handball players ( n = 20) and sedentary controls ( n = 18). Between-group differences and correlations were computed to assess study hypotheses. No differences were observed in HRV frequency-dependent parameters between groups, but in athletes, Min. R-R ( p < 0.01) and Avg.R-R ( p = 0.03) before WAnT-30 and the percentage of successive normal cardiac beat intervals greater than 50 milliseconds (i.e., pNN50; p = 0.03) after WAnT-30 were elevated. A high positive correlation was detected between the pretest and post-test cortisol levels in athletes ( p = 0.0001; r = 0.87) but not in sedentary individuals. No correlations were observed between the cortisol levels and WAnT-30 power parameters in either group. Relationships were evident in the standard deviation of RR intervals ( p = 0.02, r = -0.53), square root of the mean squared difference of successive RR intervals ( p = 0.043, r = -0.46), very low frequency ( p = 0.032; r = -0.480), high-frequency ( p = 0.02; r = -0.52) variables, and pretesting cortisol in athletes. These findings suggest that HRV analysis is a valuable tool for examining cardiovascular regulation, independent of cortisol; the data may provide valuable information for performance teams in evaluating acute stress.

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.

Changes in Specific Biomarkers Indicate Cardiac Adaptive and Anti-inflammatory Response of Repeated Recreational SCUBA Diving

Objective

Recreational SCUBA (rSCUBA) diving has become a highly popular and widespread sport. Yet, information on molecular events underlying (patho)physiological events that follow exposure to the specific environmental conditions (hyperbaric conditions, coldness, immersion, and elevated breathing pressure), in which rSCUBA diving is performed, remain largely unknown. Our previous study suggested that repeated rSCUBA diving triggers an adaptive response of cardiovascular and immune system. To elucidate further molecular events underlying cardiac and immune system adaptation and to exclude possible adverse effects we measured blood levels of specific cardiac and inflammation markers.

Methods

This longitudinal intervention study included fourteen recreational divers who performed five dives, one per week, on the depth 20–30 m that lasted 30 min, after the non-dive period of 5 months. Blood samples were taken immediately before and after the first, third, and fifth dives. Copeptin, immunoglobulins A, G and M, complement components C3 and C4, and differential blood count parameters, including neutrophil-to-lymphocyte ratio (NLR) were determined using standard laboratory methods. Cell-free DNA was measured by qPCR analysis and N-glycans released from IgG and total plasma proteins (TPP), were analyzed by hydrophilic interaction ultra-performance liquid chromatography.

Results

Copeptin level increased after the first dive but decreased after the third and fifth dive. Increases in immunoglobulins level after every dive and during whole studied period were observed, but no changes in C3, C4, and cfDNA level were detected. NLR increased only after the first dive. IgG and TPP N-glycosylation alterations toward anti-inflammatory status over whole studied period were manifested as an increase in monogalyctosylated and core-fucosylated IgG N-glycans and decrease in agalactosylated TPP N-glycans.

Conclusion

rSCUBA diving practiced on a regular basis promotes anti-inflammatory status thus contributing cardioprotection and conferring multiple health benefits.

Maternal C3 complement and C-reactive protein and pregnancy and fetal outcomes: A secondary analysis of the PEARS RCT-An mHealth-supported, lifestyle intervention among pregnant women with overweight and obesity

Objectives:

Elevated circulating levels of complement component 3 (C3) and C-reactive protein (CRP) have been linked with adverse pregnancy outcomes. Lifestyle interventions may hold potential to ameliorate these effects. We investigated the effect of an antenatal healthy lifestyle intervention on maternal C3 and CRP concentrations and assessed their relationship with maternal and fetal metabolic markers and outcomes.

Study design:

Secondary analysis of data from the Pregnancy Exercise And Nutrition Research Study (PEARS) randomized controlled trial.

Methods:

Women (n = 406) with C3 and CRP concentrations determined in early pregnancy (14–16 weeks) and/or late pregnancy (28-weeks) with corresponding fasting glucose, insulin, c-peptide, and lipid profiles were included in the analysis. Pregnancy outcomes included: diagnoses of gestational diabetes (GDM), pre-eclampsia (PET) or pregnancy induced hypertension (PIH), pre-term birth (delivery < 37 weeks), low birth weight (<2500 g), small-for-gestational age (SGA) defined using < 5th or 10th centile for birthweight and cord blood measures of glucose and lipid metabolism. T-tests investigated changes in C3 and CRP over time. Chi-square, Pearson’s’ correlations and multiple regression investigated relationships with outcomes.

Results:

The PEARS intervention did not influence maternal C3 or CRP concentrations in pregnancy. There was no relationship between CRP concentrations and any maternal or infant outcome. Women who developed GDM had higher C3 concentrations in early (p = 0.01) and late pregnancy (p = 0.02). Women who developed PIH/PET had lower C3 concentrations in early (p = 0.02), but not late (p = 0.10) pregnancy. Maternal C3 concentrations in early pregnancy were a small but significant predictor of maternal insulin concentrations in early (β = 0.40, 95% CI 0.27, 0.53; p < 0.001) and late (β = 0.30, 95% CI 0.17, 0.43p < 0.001) pregnancy, early total cholesterol (TC), and both early and late triglycerides, LDL and HDL Cholesterol concentrations (all p < 0.001). Women who delivered SGA babies (<10th centile) had lower C3 concentrations than women who did not in both early (p < 0.001) and late pregnancy (p = 0.01). No relationship between maternal C3 or CRP and fetal glucose concentrations or lipid profiles was observed.

Conclusion:

Maternal C3 may play a role in multiple adverse pregnancy outcomes including cardiometabolic ill-health. Further research on this, and strategies to reduce C3 in a pregnant population, are warranted.

High Endurance Elite Athletes Show Age-dependent Lower Levels of Circulating Complements Compared to Low/Moderate Endurance Elite Athletes

Introduction: Aerobic exercise activates the complement system in the peripheral blood. However, the effect of age and high intensity endurance training on the levels of circulating complements and sassociated inflammatory cytokines, oxidative stress markers and cellular aging remains unknown.

Methods: In this study, serum samples from 79 elite athletes who belong to high (n = 48) and low/moderate (n = 31) endurance sports and two age groups (below 30 years old, n = 53, and above 30 years old, n = 26) were profiled for 14 complements. Linear models were used to assess differences in complements levels between sport and age groups. Spearmann’s correlation was used to assess the relationship among detected complements and proinflammatory cytokines, oxidative stress markers and telomere lengths.

Results: High endurance elite athletes exhibited significantly lower levels of circulating C2, C3b/iC3b and adipsin complements than their age-matched low/moderate endurance counterparts. Levels of C2, adipsin and C3b/iC3b were positively correlated with most detected complements, the pro-inflammatory cytokines TNF-alpha and IL-22 and the anti-oxidant enzyme catalase. However, they were negatively correlated with telomere length only in younger elite athletes regardless of their sport groups. Furthermore, high endurance elite athletes showed significantly lower concentrations of C3b/iC3b, C4b, C5, C5a, C1q, C3, C4, factor H and properdin in younger athletes compared to their older counterparts.

Conclusion: Our novel data suggest that high endurance elite athletes exhibit age-independent lower levels of circulating C2, C3b/iC3b and adipsin, associated with lower inflammatory, oxidative stress and cellular aging, as well as lower levels of 10 other complements in younger athletes compared to older counterparts. Assessing the effect of various levels of endurance sports on complements-based immune response provides a better understanding of exercise physiology and pathophysiology of elite athletes.

Multi-Micronutrient Supplementation and Immunoglobulin Response in Well-Fed Firefighters

Intensive physical training programs can affect the immune system. This study aims to verify the multi-micronutrient supplementation effects on serum immunoglobulins levels prior to and after a five-week physical training program. Twenty-four male recruit firefighters were randomly allocated into supplemented (with Prisfar Ever-Fit Plus over 35 consecutive days) and placebo groups (n=12 each). Serum immunoglobulins G, A, and M were assessed. Supplementation effect was detected for immunoglobulin G (eta-squared, η ² : 0.09; p =0.035; power: 0.56), A (η ² : 0.24; p =0.001; power: 0.95), and M (η ² : 0.09; p =0.036; power: 0.56). Although immunoglobulin A was different between groups at baseline (mean difference: 42.58; 95%CI: 7.00 to 78.16 mg/dL; p =0.021; d =2.48), within-group (before vs . after five weeks) showed no differences for both supplemented and control groups. In addition, even if immunoglobulin G and M were similar at baseline, immunoglobulin G decreased (mean diff.: 46.4; 95%CI: 6.7 to 86.1 mg/dL; p =0.03; d =0.74) and immunoglobulin M increased (mean diff.: -10.7; 95%CI: -15.8 to -5.5 mg/dL; p =0.001; d =-1.33) in the control group. Although mean values remained within the reference values, changes observed for immunoglobulin G and M may reflect some immune protection for firefighters engaged in recruit training.

Effect of Aerobic and Anaerobic Exercise on the Complement System of Proteins in Healthy Young Males

This study was aimed at examining the impact of common types of physical efforts used to determine the aerobic and anaerobic performance of the participants on the complement system in their peripheral blood. Fifty-one physically active young males aged 16 years old (range 15–21 years) were divided into two age groups (younger, 15–17 years old and older, 18–21 years old) and performed two types of intensive efforts: aerobic (endurance; 20-m shuttle run test; Beep) and anaerobic (speed; repeated speed ability test; RSA). Venous blood samples were collected before and after each exercise (5 and 60 min) to profile the complement system components, namely the levels of C2, C3, C3a, iC3b, and C4. The endurance effort caused a decrease in the post-test C3 (p < 0.001 for both age groups) and increase in post-test C3a (p < 0.001 and p < 0.01 for the younger and older group, respectively), recovery iC3b (p < 0.001 and p < 0.05 for younger and older group, respectively), recovery C2 (p < 0.01 for both age groups), and post-test C4 (p < 0.05 and p < 0.01 for the younger and older group, respectively) levels, while the speed effort caused a decrease only in the post-test C2 (p < 0.05 for younger participants) and post-test C4 levels (p < 0.001 and p < 0.01 for the younger and older group, respectively) and an increase in the recovery C3a level (p < 0.05). Our study provides evidence that different types of physical effort promote different immune responses in physically active young men. Aerobic exercise induced the activation of an alternative pathway of the complement system, whilst the anaerobic effort had little influence. A better understanding of the post-exercise immune response provides a framework to prescribe physical activity to achieve different health outcomes.

The compelling link between physical activity and the body's defense system

This review summarizes research discoveries within 4 areas of exercise immunology that have received the most attention from investigators: (1) acute and chronic effects of exercise on the immune system, (2) clinical benefits of the exercise-immune relationship, (3) nutritional influences on the immune response to exercise, and (4) the effect of exercise on immunosenescence. These scientific discoveries can be organized into distinctive time periods: 1900-1979, which focused on exercise-induced changes in basic immune cell counts and function; 1980-1989, during which seminal papers were published with evidence that heavy exertion was associated with transient immune dysfunction, elevated inflammatory biomarkers, and increased risk of upper respiratory tract infections; 1990-2009, when additional focus areas were added to the field of exercise immunology including the interactive effect of nutrition, effects on the aging immune system, and inflammatory cytokines; and 2010 to the present, when technological advances in mass spectrometry allowed system biology approaches (i.e., metabolomics, proteomics, lipidomics, and microbiome characterization) to be applied to exercise immunology studies. The future of exercise immunology will take advantage of these technologies to provide new insights on the interactions between exercise, nutrition, and immune function, with application down to the personalized level. Additionally, these methodologies will improve mechanistic understanding of how exercise-induced immune perturbations reduce the risk of common chronic diseases.

Associations of aerobic and strength exercise with clinical laboratory test values

OBJECTIVES

Physical exercise may affect levels of blood-based biomarkers. However, exercise status is seldom considered in the interpretation of laboratory results. This study reports the associations between habitual exercise participation and clinical laboratory test results.

METHODS

The effects of days per week of aerobic and strength exercise participation on laboratory test results for 26 biomarkers in young adults aged 18 to 34 years (n = 80,111) were evaluated using percentile distribution analyses and multivariate regression.

RESULTS

In both men and women, more days per week of either aerobic or strength exercise were significantly associated with lower levels of glucose, hemoglobin A1c, LDL cholesterol, total cholesterol, triglycerides, estimated glomerular filtration rate, globulin, and C-reactive protein, and significantly higher levels of HDL cholesterol, creatinine, iron, and percent saturation (all p < .05). Type of exercise or gender influenced the observed relationships with exercise frequency for total cholesterol, aspartate aminotransferase, gamma-glutamyl transferase, alkaline phosphatase, uric acid, bilirubin, and iron binding capacity.

CONCLUSIONS

Physical exercise shifted the distribution of results into the direction suggestive of better health. Reported relationships may help clinicians and patients to better understand and interpret laboratory results in athletic populations and possibly re-evaluate interpretation of reference intervals for physically active populations.

Micronutrient Supplementation does not Change Complement System Response to Heavy Training

We aimed to examine the micronutrient supplementation effect on complement system activity after heavy training. 24 male firefighters were randomly divided into supplemented and placebo groups, and tested for immunology-related parameters using venous blood samples in the fasting state pre- and post-5 weeks of nutritional supplementation. C3 and C4 complement components were determined in a nephelometer from immune complexes formed through specific human antisera and total haemolytic complement activity (CH100) was determined by enzyme immunoassay. Differences between pre- and post-supplementation were observed only for CH100 on placebo group (p=0.004; mean diff −26.92; 95%CI −43.58 to −10.25) and no interaction, treatment or time effects were observed for C3 and C4. Although interaction accounted for 8.8% of the total variance in CH100 (with time effect pre- vs post-accounting for 19.5% of the total variance), the treatment effect (supplemented vs placebo) was not significant. The absence of effects on the complement system response to supplementation during heavy training could be justified by the fact that: (i) nutritional supplements do not improve humoral innate immunity in well-fed subjects; (ii) selected supplements unlikely improve the innate immune system in situations of adequate nutritional status; and/or (iii) selected doses of supplementation were not sufficient to elicit immune changes.

Iron-induced necrotic brain cell death in rats with different aerobic capacity

Brain iron overload has a key role in brain injury after intracerebral hemorrhage (ICH). Our recent study demonstrated that ICH-induced brain injury was greater in low capacity runner (LCR) than in high capacity runner (HCR) rats. The present study examines whether iron-induced brain injury differs between LCRs and HCRs. Adult male LCR and HCR rats had an intracaudate injection of iron or saline. Rats were euthanized at 2 and at 24 h after T2 magnetic resonance imaging, and the brains were used for immunostaining and Western blotting. LCRs had more hemispheric swelling, T2 lesion volumes, blood-brain barrier disruption, and neuronal death at 24 h after iron injection (p < 0.05). Many propidium iodide (PI)-positive cells, indicative of necrotic cell death, were observed in the ipsilateral basal ganglia of both HCRs and LCRs at 2 h after iron injection. PI fluorescence intensity was higher in LCRs than in HCRs. In addition, membrane attack complex (MAC) expression was increased at 2 h after iron injection and was higher in LCRs than in HCRs. The PI-positive cells co-localized with MAC-positive cells in the ipsilateral basal ganglia. Iron induces more severe necrotic brain cell death, brain swelling, and blood-brain barrier disruption in LCR rats, which may be related with complement activation and MAC formation.

Hematological, oxidative stress, and immune status profiling in elite combat sport athletes

The aim of this study was to profile hematological, oxidative stress, and immunological parameters in male athletes who practiced combat sports and to determine whether the type of combat sport influenced the measured parameters. Eighteen karate professionals, 15 wrestlers, and 14 kickboxers participated in the study. Hematological, iron-related, oxidative stress, and immunological parameters were measured at the beginning of a precompetitive period. The general linear model showed significant differences between the karate professionals, wrestlers, and kickboxers with respect to their hematological and iron status parameters (Wilks' Lambda = 0.270, F = 2.186, p < 0.05) and oxidative stress status (Wilks' Lambda = 0.529, F = 1.940, p < 0.05). The immature reticulocyte fraction was significantly higher in wrestlers (0.30 ± 0.03) compared with kickboxers (0.24 ± 0.04; p < 0.05) and karate professionals (0.26 ± 0.04; p < 0.05). Low hemoglobin density was significantly lower in wrestlers and kickboxers (p < 0.05) compared with karate professionals (karate: 3.51 ± 1.19, wrestlers: 1.95 ± 1.10, and kickboxers: 1.77 ± 0.76). Significant differences were observed between the karate professionals and wrestlers with respect to their pro-oxidant-antioxidant balance (437 ± 103 vs. 323 ± 148, p < 0.05) and superoxide-dismutase activity (SOD) (73 ± 37 vs. 103 ± 30, p < 0.05). All the measured parameters (with the exception of SOD activity) fell within their physiological ranges, indicating that the study participants represented a young and healthy male population. Hematological parameters differed between kickboxers and karate professionals. The low pro-oxidant-antioxidant balance and high SOD activity in wrestlers could be associated with the long-term impact of wrestling as a type of strenuous exercise.

Moderate exercise increases the metabolism and immune function of lymphocytes in rats

Exercise modulates both glucose and glutamine metabolism which influences lymphocyte function. We investigated the influence of chronic moderate exercise on glucose and glutamine metabolism in lymphocytes, the associated influence on proliferation, and cytokine and immunoglobulin production. Male Wistar rats (8 weeks old) were placed in an exercise training group (N = 15, 1 h day(-1) at 60 % VO₂max, 5 days week(-1)) for 8 weeks of exercise, or a sedentary control group. Twenty-four hours following the final training session, lymphocytes were separated, and the incorporation of [U-14C]-glucose, [U-14C]-glutamine, and [2-14C]-thymidine from the supernatant was measured. The activity of glucose-6-phosphate dehydrogenase, hexokinase, and glutaminase was measured. Lymphocytes were stimulated with ConA and LPS and incubated with the Mycobacterium bovis bacille Calmette-Guerin (BCG) vaccine and plasma IgG and IgE were measured. Glutamine metabolism increased in both T and B lymphocytes in the trained group. In the trained group, proliferative capacity increased T lymphocytes under ConA stimulation, and increased B lymphocytes with LPS. There was a significant increase in IL-2 production and decrease in IL-4 in the trained group compared with sedentary controls. IL-2R and TNFR increased in trained rats while IL-4R decreased and were more pronounced in T lymphocytes compared with B lymphocytes. In both lymphocyte subsets, exercise training significantly increased the expression of CD54+ and CD30+ cell markers. Exercise training increased plasma IgG compared with the sedentary group. In conclusion, moderate exercise training improves immune function and metabolism in T and B lymphocytes, reflecting an increased ability to respond to immune challenges.

Gender differences in physical and psychological stress responses among college judoists undergoing weight reduction

Gender-related differences in anthropometry, blood biochemistry, psychological parameters, and energy intake during prematch weight reduction were studied in 22 men and 7 women college judoists who lost weight by combining judo training, restricting food and fluid, and sweating. Body weight (BW) decreased significantly by 2.2±1.4 kg in men and 2.0±1.4 kg in women 2 weeks after weight reduction started - not significandy different. Body fat, relative body fat and total energy intake also decreased significandy in both groups 2 weeks after weight reduction started. Lean body mass decreased significandy 2 weeks after weight reduction started only in men. Men had significantly decreased blood lipids, immunoglobulins, complements, hematocrit, white blood cell count, and serum electrolytes, and significant increases in blood uric nitrogen, creatinine, and hemoglobin, while women showed no such changes. The score for vigor in the Profile of Mood States (POMS) decreased in both groups 2 weeks after weight reduction started, but with no statistically gender difference. In women, scores for anxiety in the State-Trait Anxiety Inventory (STAI) and confusion in POMS increased significandy. Although the men and women had the same BW reduction, significant physical stress response was seen only in men, and psychological stress due to weight reduction and mental pressure of an upcoming competition were seen more in women.

Influence of a 3-month training program on muscular damage and neutrophil function in male university freshman judoists

We studied the effects of a high intensity and high frequency 3-month training program on muscle damage and neutrophil function in male judoists. The study included 15 male judoists who started intensive judo training program after a 6-month break. Creatine kinase (CK), neutrophil counts and reactive oxygen species (ROS) production capability as well as phagocytic activity (PA) of neutrophils were measured at 2 stages; entering university (pre-training) and after 3-month training (post-training). At both points, we investigated parameters three times: just before, immediately after and 24 h after a 2-h practice session. Practice-mediated change in CK was lower at post-training than at pre-training. Neutrophil count significantly increased after 2-h practice but recovered 24 h later whereas it showed no subsequent and further increased at 24 h post-practice. Although neutrophil ROS production capability and PA both decreased (breakdown) after practice session, ROS production capability increased and PA decreased (well-adapted) at the post-training. Long-term training strengthened muscular function and improved neutrophil reaction against practice-mediated stress.

Effects of soccer matches on neutrophil and lymphocyte functions in female university soccer players

In this study, changes in physical fatigue and biological functions of Japanese female soccer players were investigated by determining changes in neutrophil and lymphocyte functions. Study subjects included 18 female soccer players. Body composition, serum myogenic enzymes, neutrophil function, including reactive oxygen species (ROS) production capability, phagocytic activity (PA) and serum opsonic activity, as well as lymphocyte subpopulation were measured before and after a soccer match. Levels of myogenic enzymes (AST, ALT, CK and LDH) and immunoglobulins (IgG and IgA) and complements (C3) increased significantly after the match. In addition, leukocyte, neutrophils and lymphocyte counts increased whereas total PA decreased significantly. The number of T and Th1 cells (subsets of T helper cells) decreased whereas Th2 increased significantly. In addition, the number of B cells increased and NK cells decreased significantly after the match. The match was found to result in degenerative changes in and damage to athlete muscle tissues together with damage- and change-mediated stress. These data also suggest a post-match accelerated inflammatory reaction and potential immunosuppression as indicated by reductions in neutrophil PA and lymphocyte functions.

Changes in neutrophil functions during a 10-month soccer season and their effects on the physical condition of professional Japanese soccer players

We examined changes in neutrophil function of soccer players over a 10-month period and determined its effectiveness as an index for athlete physical condition. Subjects included 21 male professional Japanese soccer players. Data on body composition, myogenic enzymes and neutrophil function were obtained before and after 2 h of training at 3 investigation points: one week before opening season, at season mid-point, and one week before the last game of the season. As a result, change ratios of myogenic enzyme levels before and after the 2-hr training session at the third investigation point were significantly higher compared to the two other points. Reactive oxygen species production and phagocytic activity significantly increased after 2-hr training session at point 1, although the extent of the increase became smaller over time and ROS production capability decreased significantly by point 3 assessment. Fatigue, especially muscle fatigue, chronically accumulated along with a gradual decrease in neutrophil immune function over the 10-month season. Therefore, determination of neutrophil function can be used as a useful index to assess and understand an athlete's physical condition.

Effects of training on resting peripheral blood and BAL-derived leucocyte function in horses

In this study, the effects of prolonged, high intensity training on aspects of peripheral blood and bronchoalveolar lavage (BAL)-derived leucocyte function were evaluated in 8 horses. All horses undertook a 7 week endurance training programme, followed by 5 weeks of high intensity training (HIT). Thereafter, horses were divided into control (C) and overtraining (OT) groups. The frequency and intensity of training were increased more substantially for horses in the OT group. Training was terminated in week 32 when horses in the OT group demonstrated a significant performance reduction. Peripheral blood and BAL samples were collected from 4 horses in C and OT groups in training weeks 7, 11, 14, 18, 22, 28 and 32. Flow cytometric techniques were used to assess phagocytosis by peripheral blood neutrophils and pulmonary alveolar macrophages (PAM), and oxidative burst activity of neutrophils, PAM, peripheral blood and BAL-derived lymphocytes. Peripheral blood neutrophil phagocytosis (internalisation) increased during the initial HIT period and decreased from week 16 when the training workload was increased for both groups. The oxidative burst activity of peripheral blood neutrophils and lymphocytes similarly increased and then decreased in response to training. The oxidative burst activity of PAM was reduced towards the end of the overtraining phase of the programme. Pulmonary alveolar macrophage phagocytosis and oxidative burst activity of BAL-derived lymphocytes demonstrated no change throughout the course of the study. There was no difference in results obtained from C or OT group horses, suggesting that protracted HIT, rather than overtraining, was associated with impaired cell function. The detrimental effects observed in peripheral blood neitrophil and PAM function may indicate impaired nonspecific immunity which may adversely affect the health and performance of horses undergoing protracted periods of intense training.

Upper respiratory tract infection symptoms in ultramarathon runners not related to immunoglobulin status

OBJECTIVE

To determine the association between variation in exercise load, immunoglobulin (Ig) status, and self-reported symptoms of upper respiratory tract infection (URTI) in ultramarathon runners.

DESIGN

Longitudinal observational field study.

SETTING

Four weeks before and 2 weeks after an 86.5-km Comrades Marathon, South Africa.

PARTICIPANTS

Fourteen randomly selected, amateur, male, ultramarathon runners.

MAIN OUTCOME MEASURES

Daily record of training and URTI symptom incidence. Salivary IgA and IgM at 28 days, 14 days, and 1 day (01PRE) before the race, immediately post race (IPR) and 1 (01 PR), 3, and 14 days post race. Serum cortisol, IgG, IgM, and IgA concentrations at 01PRE, IPR, and 01PR.

RESULTS

Mean weekly training distance varied from 89.4 kilometers per week (28.9 kilometers per week) to 4.2 kilometers per week (6.7 kilometers per week). Absolute and relative mucosal IgA and IgM concentrations were unaffected by pre-race taper in training volume (P > 0.05). IgA and IgM secretion rates decreased post race (P = 0.018; 0.008), returning to baseline by 01PR. Blood leukocyte, serum cortisol, and serum IgG concentrations increased at IPR (P < 0.001, <0001) and 01PR (P = 0.009), respectively. Upper respiratory tract infection symptom incidence was highest at 28PRE and 7 to 14 days post race but not related to salivary IgA and IgM secretion rates. Eight subjects (57%) who reported URTI symptoms pre race also reported these during days 7 to 14 post race.

CONCLUSIONS

Upper respiratory tract infection symptom incidence was not associated with secretory Ig concentrations. Reactivation of pre-race viruses during the 2 weeks post race and exercise-induced inflammatory response are proposed as causes of the elevated URTI incidence at 28PRE and 7 to 14 days post race.

The effects of a two-hour judo training session on the neutrophil immune functions in university judoists

The present study examined the effects of judo training on neutrophil and related functions. We measured and studied changes in the neutrophil and its related functions in 22 male university judoists immediately before (Pre values) and immediately after (Post values) a 2 h training session: reactive oxygen species (ROS) production capability, phagocytic activities (PA) and serum opsonic activity (SOA). Neutrophil count in whole blood, myogenic enzymes (creatine kinase, lactate dehydrogenase, aspartate aminotransferase and alanine aminotransferase), immunoglobulins (IgG, IgA and IgM) and complements (C3 and C4) in serum were also measured. The Post values of the neutrophil count, myogenic enzymes and IgG increased significantly compared with the Pre values. ROS production capability and SOA also significantly increased following training, although PA showed a slight decrease (but not statistically significant). Taking the findings of our previous studies into consideration, three major neutrophil or related functions, namely ROS production capability, PA and SOA, might compensate for each other to maintain the overall integrity of the neutrophil immune function, in that ROS and SOA increased to compensate for the slight decrease in PA, or PA slightly decreased to compensate for the increase in ROA and SOA after exercise.

Serum concentrations of C reactive protein, alpha1 antitrypsin, and complement (C3, C4, C1 esterase inhibitor) before and during the Vuelta a Espańa

OBJECTIVES

To determine serum concentrations of proinflammatory (C reactive protein, complement C3 and C4) and anti-inflammatory (alpha(1) antitrypsin, C1 esterase inhibitor (C1-INH)) acute phase proteins in elite cyclists before and during a three week cycle tour.

METHODS

Seventeen professional cyclists participating in the Vuelta a Espańa volunteered for the study. Their mean (SD) physical characteristics were: age 28 (1) years; height 1.7 (0.06) m; weight 65 (7) kg; body fat 7.6 (0.8)%; Vo(2)max 75.3 (2.3) ml/kg/min. Venepuncture was performed on each subject 24 hours before the tour began (T0), on day 11 (the first rest day; T1) and day 21 (the second to last stage of the tour; T2). Samples at T1 and T2 were taken about 17 hours after the previous stage. Analysis of variance was used to determine changes over time. Where significance was found, a Tukey post hoc test was performed.

RESULTS

C reactive protein concentrations were consistently within the normal range, although there was a 228%, non-significant increase at T1. C3 concentrations fell within the normal range at all times assessed. C4 concentrations before the race were within the normal range and were significantly increased 10 days (T1) into the race. C1-INH concentrations did not change significantly throughout the race. alpha(1) Antitrypsin concentration before the race was at the lower end of the normal range and was only significantly raised at T2.

CONCLUSIONS

Although not as pronounced as those reported in marathon/ultramarathon runners, elite cyclists participating in a three week cycle tour experienced increases in selected proinflammatory and anti-inflammatory acute phase proteins, indicating an acute phase/inflammatory response. It is tenable that the increase in alpha(1) antitrypsin and C1-INH (anti-inflammatory mediators) at T2 served to attenuate the acute phase/inflammatory response. The lower than normal resting concentrations of the acute phase proteins supports the notion that chronic aerobic exercise induces an anti-inflammatory state.

Influence of ultra-endurance exercise on immunoglobulin isotypes and subclasses

BACKGROUND

Strenuous exercise is associated with tissue damage. This activates the innate immune system and local inflammation. Interaction between innate and adaptive immunity is essential for maintaining health, suggesting that the adaptive immune system may also be altered by exercise.

OBJECTIVES

To determine exercise induced changes in the adaptive immune system by measuring the immunoglobulin isotype and subclass response to an ultra-marathon.

METHODS

Venepuncture was performed on 11 experienced volunteers (six men, five women; mean (SD) age 43 (9.8) years) 24 hours before the projected finishing time and immediately after and 3, 24, and 72 hours after an ultra-marathon (90 km). Serum was stored at -80 degrees C. IgM, IgD, IgA, IgG, IgG1, 2, 3, and 4, and total IgE were measured.

RESULTS

The following immunoglobulins were significantly (p< or =0.05) altered after the race: IgD, immediately (-51%) and 24 hours (-41%) after; IgM 24 hours after (-23%); total IgG immediately after (+12%). There were no reports of symptoms of upper respiratory tract infections after the ultra-marathon.

CONCLUSIONS

In experienced ultra-endurance runners, alterations in immunoglobulin concentrations after a race suggest an enhanced immune response, including isotype switching, interactions with the innate immune system, and a secondary antibody response. These alterations may have a role in the maintenance of subject health after an ultra-marathon.

Effect of 6 months' training on the reactive oxygen species production capacity of neutrophils and serum opsonic activity in judoists

The effects of long-term training on the production of reactive oxygen species (ROS) from neutrophils and serum opsonic activity (SOA) remain to date unknown. The aim of this study was to evaluate the effect of 6 months training on ROS production and SOA in judoists. Fifty-six judoists were enrolled this study. White blood cell counts, serum creatine kinase (CK), asparate aminotransferase (ASAT), alanine aminotransferase (ALAT), lactate dehydrogenase (LDH) and ROS production from neutrophils, and serum opsonic activity (SOA) using the lucigenin and luminol probes, were measured before and after daily judo exercise (2 h) in March and September. The subjects started their training from March after no exercise for three months, and continued it for 6 months (until September). In March, myogenic enzymes such as CK, ASAT, LDH and neutrophil counts increased and immunoglobulins, complements and SOA decreased after daily judo exercise. Such significant changes were not seen in September. On the other hand, ROS significantly increased after daily judo exercise in both March and September, with no significant difference in the rates of change. In conclusion, 6 month training minimized the changes in SOA as well as muscle enzymes, neutrophil counts, serum immunoglobulins and complements. This could be categorized as a long-term training effect. However, no such change was seen in ROS.

Position related analysis of the appearance of and relationship between post-match physical and mental fatigue in university rugby football players

OBJECTIVE

The relationship between physical and mental fatigue in rugby players after a match was examined, taking into account the position played.

METHODS

The Profile of Mood State (POMS) test, blood biochemical parameters, and serum opsonic activity were measured for 37 university rugby football players before and after a match.

RESULTS

There were no differences in parameter changes except for blood urea nitrogen (a marker for protein catabolism) between the forwards and the backs. Regarding correlation between physical and mental fatigue, in forwards, changes in POMS scores showed a positive correlation with changes in the levels of enzymes of skeletal muscle origin, such as glutamate oxaloacetic transaminase (GOT) and lactate dehydrogenase (LDH), and free fatty acid (FFA) level and white blood cell count (for example, in the Total Mood Disturbance (TMD) score, Spearman's correlation coefficient was 0.417 and p<0.05 with GOT, 0.413 and p<0.05 with LDH, 0.462 and p<0.05 with FFA, and 0.442 and p<0.05 with white blood cell count). In backs, changes in the POMS scores showed a positive correlation with changes in the levels of lipid related parameters such as FFA and total cholesterol (for example, as regards the TMD score, Spearman's correlation coefficient was 0.481 and p<0.05 with FFA, and 0.550 and p<0.05 with total cholesterol), and showed a negative correlation with change in blood glucose level (TMD score, -0.517 and p<0.05).

CONCLUSIONS

The different exercise loading of the position played during a rugby match may cause differences in the relationship between physical and mental fatigue.

Effects of exercise on the physical condition of college rugby players during summer training camp

OBJECTIVES

To determine the effects of exercise training on physical condition in 25 college rugby players during a summer training camp, and to compare these variables by the different players' positions.

METHODS

Changes in body composition parameters and blood biochemistry were examined before and after a summer training camp.

RESULTS

Body weight and percentage body fat did not change significantly during the camp. There were significant decreases in levels of serum total cholesterol, triglycerides, phosphate, uric acid, and immunoglobulin G and M. In contrast, there were significant increases in levels of serum potassium, markers of renal, hepatic, and muscular damage (BUN, GOT, GPT, LDH, CK), and complement C4. Comparison of the changes in biochemical parameters between rugby players playing in different positions showed a significant increase in serum albumin level in the forwards, and significant decreases in serum triglyceride and sodium levels in the backs. The magnitude of change in serum LDH during the camp was significantly greater (p<0.05) for the forwards than for the backs.

CONCLUSIONS

These data suggest that, in rugby players attending a 20 day camp, exercise training resulted in muscular damage, loss of electrolytes due to sweating, and changes in immune function. Backs exhibited a higher rate of fat metabolism and loss of electrolytes than forwards, possibly because they did more running during the camp. In contrast, forwards experienced more physical contact, performed more physically strenuous exercise, and exhibited higher levels of muscular damage and tissue protein degradation.

Delayed leukocytosis after hard strength and endurance exercise: aspects of regulatory mechanisms

Background

During infections, polymorphonuclear neutrophilic granulocytes (PMN) are mobilized from their bone marrow stores, travel with blood to the affected tissue, and kill invading microbes there. The signal(s) from the inflammatory site to the marrow are unknown, even though a number of humoral factors that can mobilize PMN, are well known. We have employed a standardized, non-infectious human model to elucidate relevant PMN mobilizers. Well-trained athletes performed a 60-min strenuous strength workout of leg muscles. Blood samples were drawn before, during and just after exercise, and then repeatedly during the following day. Cortisol, GH, ACTH, complement factors, high-sensitive CRP (muCRP), IL-6, G-CSF, IL-8 (CXCL8) and MIP-1β (CCL4) were measured in blood samples. PMN chemotaxins in test plasma was assessed with a micropore membrane technique.

Results

About 5 hr after the workout, blood granulocytosis peaked to about 150% of baseline. Plasma levels of GH increased significantly 30 min into and 5 min after the exercise, but no increase was recorded for the other hormones. No significant correlation was found between concentrations of stress hormones and the subjects' later occurring PMN increases above their individual baselines. Plasma G-CSF increased significantly – but within the normal range – 65 min after the workout. IL-6 increased very slightly within the normal range, and the chemokines IL-8 and MIP-1β did not increase consistently. However, we found a significant increase of hitherto non-identified PMN-chemotactic activity in plasma 35, 50, and 60 min after the exercise. No systemic complement activation was detected, and (mu)CRP was within the reference range at rest, 5 h and 23 h after the exercise. After endurance exercise, similar findings were made, except for a cortisol response, especially from non-elite runners.

Conclusion

Apparently, a multitude of humoral factors can – directly or indirectly – mobilize PMN from marrow to blood; some of the factors are, others are not known to be, chemotactic. Under different conditions, different selections of these mobilizers may be used. In the late granulocytosis after heavy, long-lasting exercise a number of factors thought capable of mimicking the granulocytosis of infectious diseases were apparently irrelevant.

Effects of long-distance running on serum opsonic activity measured by chemiluminescence

Exhaustive exercise such as long-distance running has been shown to increase susceptibility to infection. In order to investigate whether serum opsonic activity plays a role in such conditions, we utilized luminol-dependent and lucigenin-dependent chemiluminescence (LmCL and LgCL). We took serum samples from 24 male marathon runners before and after running 30 km. Neutrophils were isolated from the peripheral blood of healthy volunteers. Serum opsonic activity was examined by measuring neutrophil ROS stimulated with zymosan particles opsonized by the serum samples. Immunoglobulin and complement levels in the serum were also measured. After a 30 km run, the maximum light emission was increased and the time to reach the maximum light emission was shortened significantly (p < 0.05) in LmCL. However, there were no significant changes in the immunoglobulin and complement levels. The increase of ROS production may suggest that serum opsonic activity is accelerated after running 30 km. Thus, serum opsonic activity might not play a significant role in the susceptibility to infection after long-distance running.

Depressed humoral immunity after weight reduction in competitive judoists

We studied changes in serum opsonic activity (SOA) in male judoists who were engaged in active weight reduction. Serum immunoglobulins, complements and SOA, measured by neutrophil-associated chemiluminescence responses, were investigated 20 days, 7 days and 1 day before a competition and 5 days after the competition. In addition, muscle strength and anaerobic work capacity, as well as body composition, were also determined. A dietary survey was conducted daily during the observation period. Body weight decreased by 4.2 kg over 19 days. SOA significantly decreased 5 days after the competition, as well as the concentrations of serum immunoglobulins, complements and total proteins. These trends were noted in the marked weight reduction group (i.e. reduction weight of body fat/body fat weight before weight reduction > or = 25%) more than the slight reduction group (<25%). Depressed SOA was closely correlated with the decreased concentrations of immunoglobulins and complements. These results suggest that the decrease in immunoglobulins and complements following weight reduction is associated with reduced SOA, which might cause susceptibility to infections. This study demonstrated that such immunosuppression appeared in the recovery period after the competition rather than immediately before the competition.

Mucosal immunity, respiratory illness, and competitive performance in elite swimmers

PURPOSE

Exercise and training are known to elicit changes in mucosal humoral immunity, but whether these alterations have any impact on competitive performance remains unclear. This investigation examined relationships between salivary immunoglobulin (Ig) concentration, the incidence of respiratory tract illness (RTI), and competitive performance in elite swimmers.

METHODS

Forty-one members of the Australian Swimming Team (21 males and 20 females) aged 15-27 yr were monitored during preparations for the 1998 Commonwealth Games. Twenty-five coaches and staff (19 males and 6 females) aged 32-65 yr, serving as "environmental controls," were also monitored. Salivary IgA, IgM, and IgG and albumin concentration (mg.L-1) were measured in both groups in May 1998 and again in August 1998, 17 d before competition. Subjects were categorized as "ill" (at least one RTI) or "healthy".

RESULTS

There were no significant changes in salivary IgA, IgM, or IgG concentration in the swimmers between May and August, nor were there any differences between healthy (N = 23) and ill (N = 18) swimmers. There was a significant positive relationship between IgM and performance in the male swimmers (r = 0.85, P < 0.001) but not for any other parameter. There was no significant difference in performance between ill and healthy swimmers (P = 0.11). Gold medal winners (N = 9) had higher IgM levels than other swimmers (N = 32) in May (P = 0.02) and higher IgG in August (P = 0.02).

CONCLUSION

These data indicate that a season of training by elite swimmers did not alter salivary immunoglobulin concentrations, and the presence of RTI had no significant impact on competitive performance.

Acute exercise effects on the immune system

PURPOSE

In recent years, health professionals have placed increased attention on the benefits of physical activity for maintaining health in the general population as well as regaining health in many disease states. Conversely, reports of apparent decreases in immune cell function after acute exercise are widespread in the literature. The purpose of this article is to evaluate critically the available data and currently employed methods, with the aim of establishing whether genuine or artefactual alterations of immune function are being reported. During and immediately after exercise, the total number of white blood cells in peripheral blood samples increases, such that the relative proportions of cell types within the leukocyte pool are altered. A number of important areas of discussion arise from these shifts in the number of circulating cells after exercise, not least of which is the artefactual effects they may have on currently employed assays of immune cell function. Recent advances in methodology are beginning to call into question the assumption that acute exercise has any genuine immunosuppressive effect.

CONCLUSION

At present, there is little evidence to suggest that the range of acute exercise intensities and durations recommended by ACSM has a major detrimental effect on the function of individual T- and B-lymphocytes, natural killer cells and neutrophils. Although individual cells may not be as adversely affected as previously supposed, it is unclear whether the numerical content of the circulating population is an important clinical consideration.

Reactivity and recovery from different types of work measured by catecholamines and cortisol: a systematic literature overview

OBJECTIVES

To review occupational health, laboratory, and sports literature on neuroendocrine reactivity and recovery from mental, combined mental and physical, or physical tasks.

METHODS

A systematic literature search was performed in eight databases. Studies with catecholamines or cortisol as effect variables measured in blood, urine, or saliva were included.

RESULTS

After application of inclusion and exclusion criteria, 77 studies from the initial 559 identified were taken into account. In occupational settings it was found that relatively few studies were conclusive about recovery, which formed a contrast with sports research. For reactivity and recovery up to 1 hour after performing the task, half of the studies considered physical tasks and more than two thirds showed incomplete recovery compared with baseline excretion of catecholamines and cortisol. Recovery extending to 3 days after the task was performed was often incomplete for cortisol after combined mentally and physically demanding tasks, and less often after solely mental or physical tasks. This type of recovery was more often incomplete for adrenaline (epinephrine) than for noradrenaline (norepinephrine), which was the case after mental as well as combined mental and physical tasks.

CONCLUSIONS

The results from laboratory and sports research may be transferable to some occupations, but more research is needed on the course of recovery relative to health effects in occupational settings.

Exercise and immunity: a review with emphasis on the horse

Exercise has been recognized as a stress, which can significantly alter the host's immune response and, therefore, its susceptibility to disease. Whereas research in this area has previously focused primarily on human subjects and laboratory animals, it has more recently extended to domestic animals, especially the equine athlete. Despite several studies, defining the relationship among exercise, the immune response, and disease has proven difficult due to a number of factors, including the complexity of the immune system and the variable nature of exercise itself. It now appears that exercise has dual effects on the immune system. Suppressive effects, such as a decline in the ratio of CD4+ to CD8+ cells, diminished lymphocyte function, and a decline in the number and cytolytic activity of natural killer cells have been observed in response to brief high-intensity exercise, prolonged exhaustive exercise, and overtraining. In contrast, moderate training generally has beneficial effects on host defense mechanisms. The mechanisms for regulating the dual effects of exercise are complex, involving a network of neuroendocrine hormones and cytokines.

The effects of incremental submaximal exercise on circulating leukocytes in physically active and sedentary males and females

To study the effects of exercise on circulating leukocytes and leukocyte subsets, physically active (n = 32) and sedentary (n = 32) male and female subjects were randomly assigned to an exercise or control condition. Exercise involved a continuous incremental protocol consisting of cycling for three periods of 6 min at power outputs corresponding to 55%, 70% and 85% maximal oxygen uptake (VO2max). Blood samples were drawn from a venous catheter at baseline, and at 6 min, 12 min, and 18 min after beginning the exercise and 2 h following completion of exercise. Resting- and exercise-induced alterations in total leukocytes were independent of gender and subject fitness level. Relative to baseline, each increment in workload resulted in a rapid increase in the number of circulating leukocytes. Increases in neutrophils, lymphocytes and monocytes accounted for the exercise-induced leukocytosis. With regard to lymphocytes, exercise resulted in a significant increase in the number of T cells (CD3+), T helper cells (CD4+), T suppresser (CD8+) and natural killer (NK) cells (CD3-/CD16+/CD56+). The largest percentage increase occurred in the NK cell population. The CD4+: CD8+ ratio decreased (P < 0.001) throughout exercise due to a larger increase in the number of CD8+ cells relative to CD4+ cells. An exercise-induced neutrophilia, lymphocytopenia, and eosinophelia was observed 2 h into recovery. Exercise resulted in significant increases in plasma epinephrine and norepinephrine levels. There was no indication of a hypothalamic-pituitarty-adrenal response during exercise. The results indicate that the rapid, albeit transient, alteration in the number of circulating leukocytes during and following an acute progressive incremental exercise test are independent of gender and fitness.

Impact of physical activity and sport on the immune system

This review describes how exercise and physical training affect the immune system. Although many immune functions are stimulated by moderate physical activity, more vigorous effort and periods of heavy training suppress various immune response parameters. Experimental studies from our own laboratories and elsewhere illustrate that cellular infiltration of the active muscle is accompanied by phagocyte activation, suppressed NK-cell function, impaired lymphocyte proliferation, decreased in-vitro immunoglobulin production, pro-inflammatory eicosanoid release, cytokine cascade activation, and altered expression of cytokine receptors. Examples cover deliberate heavy training; single bouts of fatiguing, submaximal work; repeated bouts of exercise; and ultra-long distance athletic events. In young adults, age, environment, and light physical training do not change immune-response parameters. Parallels between immune impairment after vigorous exercise and reactions to surgical sepsis are noted. Vigorous exercise probably induces subclinical muscle injury and an associated inflammatory response. Heavy exercise may be a useful experimental model for developing more effective treatments for sepsis. For protection average athletes may take the anti-oxidant vitamins C and E and non-steroidal inflammatory drugs, if the muscles show signs of an inflammatory reaction. Top-level athletes have received immunoglobulin preparations.

Potential impact of physical activity and sport on the immune system--a brief review

Description is given of methods that can evaluate the main functional elements of the immune system. Acute responses to exercise depend on the intensity and duration of the required activity relative to the individual's fitness level. Moderate endurance exercise causes either no change or an enhancement of such indices as total leucocyte count, granulocyte, monocyte, lymphocyte and natural killer cell count, total T cell count, helper:suppressor cell ratio, cell proliferation in response to mitogens, serum immunoglobulin levels, and in vitro immunoglobulin production. However, exhausting exercise tends to produce adverse changes in these same indices, particularly if the physical activity is accompanied by environmental or competitive stress. Moderate, appropriately graded training reduces reactions to any given absolute intensity of exercise. When pursuing a more demanding training regimen, it is important that the exerciser optimize immune responses. If athletic preparation is pursued to the level of staleness and/or muscle damage, it can have substantial negative implications for many aspects of immune function, including resistance to acute infections, HIV infections, ageing, cancer and other conditions influenced by the immune system.

Infection in athletes

Coaches and athletic team physicians have provided anecdotal information and case studies to support their beliefs that athletes may be unusually prone to illness during strenuous training or competition. Many athletes, in contrast, believe that physical activity improves their resistance to infectious disease. However, it is generally agreed that the stress of competition may make athletes temporarily more susceptible to infectious illness. A review of the literature shows that upper respiratory tract infections and skin infections are more prevalent in top level athletes than in the general population, particularly during periods of intensive training. Exercise induced changes occur in both the innate and adaptive components of the immune system; however, the relative importance of each component is unknown. Strenuous exertion and contact sports may compromise host defence both by reducing physical protection and by impairing immunosurveillance. Skin lacerations, vigorous sweating and maceration of the dermis impair the defence normally provided by the skin surface. In addition, adverse changes in soluble and cellular components of the immune system can increase susceptibility to infection. Persistence with strenuous training during an infectious illness can have deleterious effects; not only is athletic performance impaired, but the severity of the disease process can be augmented.

The effects of acute and chronic exercise of immunoglobulins

The effects of acute exercise (both graded-maximal and submaximal) and exercise training on resting immunoglobulin levels and immunoglobulin production are reviewed. Brief graded-maximal or intensive short term submaximal exercise tends to be associated with increases in serum immunoglobulins, the pattern of which does not vary between athletes and nonathletes. Plasma volume changes appear to largely explain these acute increases. Acute moderate exercise, such as a 45-minute bout of walking, on the other hand, has been associated with a transient rise in serum immunoglobulin levels despite no change in plasma volume. This increase is probably the result of contributions from extravascular protein pools and an increased lymph flow. Total serum immunoglobulin changes following less than 40 km of running are minor and/or statistically insignificant, although the concentration of IgG is observed to be at its lowest by 1.5 hours after exercise. The greatest effect of acute submaximal exercise appears to be on serum IgM levels which tend to increase, although results are somewhat inconsistent. Various mechanisms of stimulation have been proposed to explain the exercise-induced effect on IgM, which is the first antibody class produced in an immune response. These mechanisms include nonspecific noradrenergic sympathetic neural interactions with the immune system and the possibility of antigen stimulation through greater-than-normal quantities of microorganisms entering the body through both increased ventilation rates and breakdown of natural mucosal immunity by drying of airway secretions. When athletes run 45 to 75 km at high intensities, serum immunoglobulin levels have been reported to be depressed for up to 2 days. Thus intense ultramarathon running may lead to greater and longer lasting decreases in serum immunoglobulin levels than following exercise of shorter duration. IgA and IgG, immunoglobulins commonly found in airway and alveolar space secretions, may have diffused from the serum during recovery from prolonged endurance exercise nonspecifically and/or in response to microbial agents and antigens introduced into the airways during the exercise bout. It has been well established that prolonged endurance exercise is associated with muscle cell damage and local inflammation. It has been hypothesised that natural (IgM) autoantibodies may be used to assist macrophages in disposal of muscle cell breakdown products. This could occur either by IgM binding to breakdown products present in the blood, followed by their clearance from the circulation, or it is possible that these antibodies may leave the circulation to carry out this same function in tissues.(ABSTRACT TRUNCATED AT 400 WORDS)

Sports-Aggravated Allergies

In brief Many people suffer from asthma MH and other allergic conditions. Participating in sports exposes these people both to specific allergens and to nonspecific factors that will influence the presentation of their allergic symptoms. Allergy patients experience both beneficial and deleterious effects of sports participation. For the patient whose symptoms are triggered or aggravated by sports activity, treatment should focus on avoiding or modifying the triggering factors either through physical means or through the use of pharmacologic agents.