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Low-cost on-the-job peer training of nurses improved immunization coverage in Indonesia.

In Indonesia responsibility for immunizations is placed on local government health centres and on the nurses who provide the immunizations at each centre. An on-the-job peer training programme for these nurses, which was designed to improve the immunization performance of poorly performing health centres in terms of coverage and practice in Maluku province, was evaluated. Experienced immunization nurses were sent to health centres where nurses were inexperienced or performing poorly; the experienced nurses spent 1-2 weeks providing on-the-job training for the less experienced ones. An evaluation of the 13 centres that participated in the programme and the 95 that did not found that the programme increased both immunization coverage and the quality of practice. Coverage of diphtheria/pertussis/tetanus (DPT), polio, and measles vaccinations rose by about 39% in all 13 participating centres when compared with non-participating centres, and by about 54% in the 11 centres that had a functioning transportation system during the year after training. These results reflect increases in the actual number of doses given and improvements in the accuracy of reports. Potential threats to the study's validity were examined and found not to be significant. The out-of-pocket cost of the training programme was about US$ 53 per trainee or about US$ 0.05 per additional vaccine reported to have been given. The marginal cost per additional fully immunized child was estimated to be US$ 0.50.

Cost-Benefit Analysis↗

The effect of exercise training on aerobic fitness, immune indices, and quality of life in HIV+ patients.

PURPOSE: Thirty four HIV+ patients participated in a 6-wk aerobic exercise training program to determine whether exercise improved aerobic fitness, immune indices, and quality of life. METHODS: Subjects were assigned to three groups: control (no regular aerobic exercise), moderate exercise, and heavy exercise training. At study entry and exit (in each subject) we evaluated aerobic function with a symptom limited cardiopulmonary exercise test, immune indices with CD4 counts and Candida skin tests, viral replication with plasma HIV RNA measurements, and quality of life with a HIV+ population validated questionnaire. RESULTS: Aerobic fitness increased significantly in both exercise groups relative to the control group; immune indices changed very little among all three groups; however, the Candida skin tests (mm2) increased significantly in the moderate group; viral replication was essentially unchanged in all three groups; quality of life (QOL) markers improved in both exercising groups but not the control group. There were no opportunistic infections during the study. CONCLUSIONS: Exercise training resulted in a substantial improvement in aerobic function while immune indices were essentially unchanged. Quality of life markers improved significantly with exercise. Exercise training is safe and effective in this patient group and should be promoted for HIV+ patients.

Adult↗

Exercise training-induced adaptations of immune response are mediated by beta-adrenergic receptors in aged but not young mice.

Beta-adrenergic blockade was used to determine whether the exercise training-induced adaptations of immune response to viral infection were mediated by catecholamines in young and old mice. Young (2 mo) and older (16 mo) male BALB/c mice were randomly assigned to an exercise or control group, and half of the mice in each group received the beta-adrenergic receptor antagonist nadolol. After 8 wk of moderate exercise training, mice were challenged with herpes simplex virus (HSV) 24 h postexercise. The results showed that exercise treatment increased anti-HSV IgM antibody, enhanced IL-10, and altered the kinetics of IFN-gamma and IL-2 production in young and old mice. Unique to older mice, exercise decreased mitogen-induced proliferation, increased splenocytes, and tended to decrease memory cells (CD44(hi+)). In contrast, exercise increased mitogen-induced proliferation but decreased the number of splenic lymphocyte and CD4+ cells in young mice. beta-Adrenergic blockade blunted the exercise-induced changes in anti-HSV IgM, IL-2, IFNgamma, and mitogen-induced proliferation in old but not young mice. The findings suggest that some of the immunomodulatory effects of chronic exercise are mediated via beta-adrenergic receptors and that the role of beta-adrenergic receptors is age dependent.

Adaptation, Physiological↗

Effects of bovine colostrum supplementation on immune variables in highly trained cyclists.

The aim of this study was to investigate the influence of low-dose bovine colostrum protein concentrate (CPC) supplementation on selected immune variables in cyclists. Twenty-nine highly trained male road cyclists completed an initial 40-km time trial (TT(40)) and were then randomly assigned to either a supplement (n = 14, 10 g bovine CPC/day) or placebo group (n = 15, 10 g whey protein concentrate/day). After 5 wk of supplementation, the cyclists completed a second TT(40). They then completed 5 consecutive days of high-intensity training (HIT) that included a TT(40), followed by a final TT(40) in the following week. Venous blood and saliva samples were collected immediately before and after each TT(40), and upper respiratory illness symptoms were recorded over the experimental period. Compared with the placebo group, bovine CPC supplementation significantly increased preexercise serum soluble TNF receptor 1 during the HIT period (bovine CPC = 882 +/- 233 pg/ml, placebo = 468 +/- 139 pg/ml; P = 0.039). Supplementation also suppressed the postexercise decrease in cytotoxic/suppressor T cells during the HIT period (bovine CPC = -1.0 +/- 2.7%, placebo = -9.2 +/- 2.8%; P = 0.017) and during the following week (bovine CPC = 1.4 +/- 2.9%, placebo = -8.2 +/- 2.8%; P = 0.004). Bovine CPC supplementation prevented a postexercise decrease in serum IgG(2) concentration at the end of the HIT period (bovine CPC = 4.8 +/- 6.8%, P = 0.88; placebo = -9.7 +/- 6.9%, P = 0.013). There was a trend toward reduced incidence of upper respiratory illness symptoms in the bovine CPC group (P = 0.055). In summary, low-dose bovine CPC supplementation modulates immune parameters during normal training and after an acute period of intense exercise, which may have contributed to the trend toward reduced upper respiratory illness in the bovine CPC group.

Adult↗

Performance enhancement with maintenance of resting immune status after intensified cycle training.

BACKGROUND: Unaccustomed intense endurance exercise is associated with short-term suppression of natural immunity. However, it is not established whether intensified endurance training alters resting immune status or increases the risk of upper respiratory infection (URI). PURPOSE: This study examined the effect of intensified endurance training for performance enhancement on resting immune status in nine healthy, male competitive cyclists. DESIGN: Data were collected during 4 weeks of usual training (baseline), followed by prescribed cycle training that consisted of volume-building at customary training intensity (V phase, 6 weeks), unaccustomed very high intensity interval training at 100% maximal heart rate (I phase, 18 days), and an unloading taper (U phase, 10 days). METHODS: The main performance criterion was a simulated 20 km time-trial. Aerobic capacity measures included power output at ventilatory threshold (POT(vent)) and maximal oxygen uptake (VO(2max)). Markers of immune status (lymphocyte subset counts, serum cytokine levels, and new URI cases) and physiological indicators of training stress (cycling economy, 24-hour urinary cortisol excretion, and serum testosterone concentration) were evaluated in the rested state, 36 to 44 hours postexercise, during baseline, and after each training phase. RESULTS: Time-trial performance, POT9(vent), VO(2max), and cycling economy improved significantly (p < 0.001) after the V phase, and remained higher than baseline (p < 0.001) after the I and U phases. As compared with the V phase, performance time was faster after the U phase (p < 0.01). In contrast, lymphocyte counts, cytokine levels, incidence of URI, cortisol excretion, and serum testosterone concentration were not significantly different from baseline in any phase. CONCLUSIONS: Cycling efficiency and performance improved while resting immune status was maintained throughout the 10-week training program. This study provides encouraging data in support of immunological robustness during intensified endurance training.

Adult↗

The effects of anabolic steroids and strength training on the human immune response.

The immune response was assessed in 13 competitive bodybuilders self-administering anabolic-androgenic steroids and ten competitive bodybuilders not administering these drugs. Laboratory assessment included the number and relative distribution of T-cells, T-helper/inducer cells, T-cytotoxic/suppressor cells, activated T-cells, lymphocyte transformation to the mitogens, pokeweed mitogen (PWM), phytohemagglutinin (PHA), Concanavalin-A (CON-A), Staphylococcus aureus Cowan strain I (SAC), serum immunoglobulins, and natural killer (NK) activity. There were no significant differences in T-cell subsets among steroid users and non-users, but lymphocyte transformation studies revealed that the anabolic-androgenic steroid-using group had enhanced proliferative ability to the B-cell mitogen, SAC, in comparison to non-bodybuilding controls. NK activity was significantly (P less than 0.05) augmented in the anabolic-androgenic steroid users but not in the non-using bodybuilders. Serum immunoglobulin levels, in particular IgA, were significantly (P less than 0.017) lower in the steroid-using group. Four of 13 steroid users and three of eight non-steroid-using bodybuilders had detectable antinuclear antibodies. These studies indicate that 1) anabolic-androgenic steroid use as practiced by contemporary athletes is a potent modulator of immune responsiveness and 2) autoantibodies are prevalent in strength-trained men even in the absence of anabolic steroid use.

Anabolic Agents↗

Knowledge, attitudes, and beliefs of school nurses and personnel and associations with nonmedical immunization exemptions.

OBJECTIVES: We studied school personnel involved in the review of student's immunization status to determine whether personnel training, immunization-related knowledge, attitudes, and beliefs, use of alternative medicine, and sources of vaccine information were associated with the vaccination status of school children. METHODS: Surveys were mailed to a stratified and random sample of 1000 schools in Colorado, Massachusetts, Missouri, and Washington. School personnel reported their training and perceptions of disease susceptibility/severity, vaccine efficacy/safety, key immunization beliefs, use of alternative medicine, confidence in organizations, sources, and credibility of vaccine information, and the rates of vaccine exemptors in their schools. Logistic regression analysis was used to explore associations between personnel factors and beliefs (independent variables) with the likelihood of a child having an exemption (dependent variable). Regression models were adjusted for clustering of children in schools, type of school (public versus private), and state. RESULTS: Surveys were returned by 69.6% of eligible participants. A child attending a school with a respondent who was a nurse was significantly less likely to be have an exemption than a child attending a school with a respondent who was not a nurse (odds ratio [OR]: 0.39; 95% confidence interval [CI]: 0.28-0.56). The majority of respondents believed that children (95.6%) and the community (96.1%) benefit when children are vaccinated. Nurses were more likely than nonnurses to hold beliefs supporting the utility and safety of vaccination. Greater perceived disease susceptibility and severity and vaccine efficacy and safety were associated with a decreased likelihood of a child in the school having an exemption. Vaccine misconceptions were relatively common. For example, 19.0% of respondents were concerned that children's immune systems could be weakened by too many immunizations, and this belief was associated with an increased likelihood of a child in the school having an exemption (OR: 1.51; 95% CI: 1.00-2.28). Most respondents had a moderate amount or great deal of confidence in state health departments (91.4%), the Centers for Disease Control and Prevention (CDC) (93.9%), local health departments (88.8%), health care providers (88.5%), the Food and Drug Administration (73.6%), and the health care system (65.2%). Fewer respondents had a moderate amount or great deal of confidence in the media (17.4%). A child attending a school with a respondent who had a moderate amount or great deal of confidence in local and state health departments was less likely to have an exemption (OR: 0.47 and 0.44; 95% CI: 0.27-0.80 and 0.25-0.80, respectively) than a child attending a school with a respondent who did not have a moderate amount or great deal of confidence in local and state health departments. Confidence in other groups was not associated with the likelihood of a child in the school having an exemption. Nearly half (45.5%) of the respondents or their immediate family members had used some form of alternative medicine in the last 5 years. A child attending a school with a respondent who had (or had a family member[s] who) used an alternative medicine practitioner was more likely to have an exemption than a child attending a school with a respondent who had not used an alternative medicine practitioner. There were significant associations between sources used and perception of reliability for vaccine information with the likelihood of a child in the school having an exemption. Use of professional organizations, government resources, vaccine companies, and pharmacists for vaccine information were associated with a decreased likelihood of a child in the school having an exemption. Perceiving health departments and the CDC as a good or excellent source for vaccine information was associated with a decreased likelihood of a child in the school having an exemption. CONCLUSIONS: The training, knowledge, attitudes, and beliefs of school personnel who work with parents on immunrk with parents on immunization issues were associated with the likelihood of a child in the school having an exemption. Although respondents generally believed in vaccinations, misconceptions were common. Many school personnel seem to be unaware of the seriousness of some vaccine-preventable diseases and that unimmunized children are highly susceptible to diseases. These misperceptions were associated with an increased likelihood of a child having an exemption. This study of associations cannot determine causal associations. Nonetheless, the frequency of vaccine misconceptions among school personnel warrants vaccine communication programs for school employees who work with parents on immunization issues. An intervention study could determine whether such programs have an impact on parental decisions to claim exemptions for their children. Personnel without formal health care training who advice parents on immunization issues could be passing on misinformation to parents. Nurses or properly trained health personnel should be the primary school contacts for parents on immunization issues. Health departments and health care providers were used most often by school personnel for vaccine information. Providers, professional organizations, health departments, and the CDC were considered most credible. The CDC may be an underutilized source, given its high credibility; only 58.1% of respondents reported using the CDC for vaccine information. Greater visibility of CDC on vaccine information statements and communication efforts from the CDC directly to school personnel will likely be well received. Respondents who do not consider health departments and the CDC as credible sources were associated with a greater likelihood of a child in their school having an exemption. The CDC may need to consider working with other reliable sources to communicate with these personnel. Studies are needed to understand why some parents choose to forgo vaccination for children who do not have true medical contraindications to vaccines. School personnel trained in vaccine safety may serve as a valuable source of vaccine information for parents. Parents who have misconceptions about vaccines would likely benefit from discussions with health care providers. Additional public-information campaigns regarding misconceptions and the value of vaccination may be needed.

Allied Health Personnel↗

Immune responses and increased training of the elite athlete.

Ten elite male runners (age, 29.8 +/- 1.7 yr; maximum oxygen consumption, 65.3 +/- 4.9 ml.kg-1.min-1; 10-km times, 31 min 43 s +/- 1 min 46 s) deliberately increased training schedules by an average of 38% for 3 wk. Resting heart rate and maximal oxygen intake were unchanged, but the heart rate response to acute exercise was decreased. Following heavy training, blood samples taken at rest showed trends to a decreased helper/suppressor cell ratio, an increased phytohemagglutinin (PHA)- and concanavalin (ConA)-stimulated lymphocyte proliferation, and a decreased production of immunoglobulins IgG and IgM. Whereas PHA-stimulated lymphocyte proliferation was initially unchanged by acute exercise, after 3 wk of heavy training the same acute exercise caused an 18% suppression of proliferation. Acute exercise following heavy training did not alter pokeweed-stimulated IgG or IgM synthesis. There was no correlation between changes in lymphocyte subpopulations, helper/suppressor ratios, and mitogen-induced cellular proliferation. The immune system of endurance-trained athletes at rest seemed to tolerate the stress of heavy training, but superimposition of a bout of acute exercise on the chronic stress of heavy training resulted in immunosuppression, which was transient and most likely not of clinical significance.

Adult↗

Aspects of leukocyte function and the complement system following aerobic exercise in young female gymnasts.

Recent studies have reported reduced immunity in trained athletes. Scant information exists on changes in the immune function among trained children. The purpose of this study was to assess the effect of aerobic exercise on the phagocytic process of neutrophils and the complement system in young athletes. Subjects included prepubertal elite female gymnasts (n = 7) and untrained girls (n = 6) aged 10-12 years. Venous blood was withdrawn before, immediately post and 24 h following a 20-min run at a heart rate of 170-180 beats.min-1. Neutrophil random migration, chemotactic activity, bactericidal function and PMA/FMLP-stimulated superoxide anion release as well as various complement components were assessed. Net chemotaxis was found reduced (P < 0.05) 24 h following exercise (58 +/- 11 vs. 36 +/- 11 cells/field in gymnasts and 47 +/- 7 vs. 42 +/- 8 cells/field in untrained girls pre- and 24 h post-exercise, respectively). The basal values, as well as post-exercise values of bactericidal activity were lower (P < 0.05) in gymnasts as compared with the control group (0.8 +/- 0.3, 0.8 +/- 0.2 and 0.8 +/- 0.1 log decrease of colonies in gymnasts at pre-, immediately post-, and 24 h post-exercise, respectively and 1.1 +/- 0.1, 1.1 +/- 0.1 and 1.0 +/- 0.2 log decrease of colonies in controls, respectively). No significant effect on the bactericidal activity was observed in either group following exercise. The addition of homologous sera did not correct the bactericidal activity. PMA-stimulated superoxide anion release decreased (P < 0.05) among gymnasts immediately following exercise (5.7 +/- 0.4 vs. 4.4 +/- 1.0 mmol O2/10(6) PMN.min) and remained low 24 h later. The same trend was observed in FMLP-stimulated neutrophils but the data were not significant. Significantly decreased levels (P < 0.05) of the early complement components (C1Q, C1R) were also found following exercise (1.34 +/- 0.64 vs. 1.27 +/- 0.28 and 1.09 +/- 0.07 vs. 1.02 +/- 0.06 pre- and post-exercise in gymnasts and untrained, respectively). Furthermore, consistently lower C2 and C3 were observed in gymnasts compared with controls. Neutrophil dysfunction as well as impairment of the complement system seem to occur following exercise.

Analysis of Variance↗

Similarities and differences of the immune response to exercise and trauma: the IFN-gamma concept.

Similar to physical fitness, fitness of the immune system requires training. Animals that have been raised under sterile conditions have a poor immune system and fail to thrive. "Immune training" is normally provided by contact with live microorganisms or immunizations. Increasing evidence has suggested that moderate sports can decrease the frequency of infections while excessive, exhausting exercise can lead to the opposite, a situation that has been described by a J-curve. Following prolonged exhausting exercise, a transient partial suppression of several immune functions can be shown, and it has been suggested that this period provides a window for invasion of microbes. On the basis of data showing that endotoxin-inducible interferon-gamma (IFN-gamma) production is virtually abrogated for a short period following excessive exercise, we present the hypothesis that the rigorous regulatory blockade of one of the ways of IFN-gamma induction may be critically involved in causing the transient immunosuppression following exhaustive exercise stress.

Animals↗

Immune response to exercise training and/or energy restriction in obese women.

PURPOSE: The effect of exercise training (five 45-min walking sessions/wk at 60-75% maximum heart rate) and/or moderate energy restriction (4.19-5.44 MJ or 1,200-1,300 kcal x d(-1)) on innate and adaptive immunity (including mitogen-stimulated lymphocyte proliferation (MSLP), natural killer cell activity (NKCA), and monocyte and granulocyte phagocytosis and oxidative burst (MGPOB) was studied in obese women (N = 91, age 45.6 +/- 1.1 yr, body mass index 33.1 +/- 0.6 kg x m(-2)) randomized to one of four groups: control (C), exercise (E), diet (D), exercise, and diet (ED). METHODS: Aerobic power, body composition, and immune function were measured in all subjects before and after a 12-wk diet intervention period, with data analyzed using a 4 x 2 repeated measures design. All subjects self-reported symptoms of sickness in health logs using a precoded checklist. Statistical significance was set at P < or = 0.05. RESULTS: Data from this study indicate that although exercise training was unrelated to any significant changes in resting immune function, the number of days with symptoms of upper respiratory tract infection (URTI) was reduced relative to subjects in the nonexercise groups (5.6 +/- 0.9 and 9.4 +/- 1.1 sickness days, respectively, P < 0.05). Energy restriction and weight loss (7.9 +/- 0.7 kg) was associated with a significant decrease in MSLP, but no change in NKCA, MGPOB, or URTI. CONCLUSION: The data are consistent the viewpoint that weight loss, even at a moderate rate, is associated with a decrease in mitogen-stimulated lymphocyte proliferation without a change in various measures of innate immunity of the blood compartment.

Adult↗

The effect on immunity of long-term intensive training in elite swimmers.

The impact of long-term training on systemic and mucosal immunity was assessed prospectively in a cohort of elite swimmers over a 7-month training season in preparation for national championships. The results indicated significant suppression (P < 0.05) of serum IgA, IgG and IgM and salivary IgA concentration in athletes associated with long-term training at an intensive level. There was also a trend towards lower IgG2 subclass levels in serum in athletes compared with controls (P = 0.07). There were no significant changes in numbers or percentages of B or T cell subsets, but there was a significant fall in natural killer (NK) cell numbers and percentages in athletes over the training season (P < 0.05). After individual training sessions there was a significant decrease in salivary IgA levels for athletes compared with controls (P = 0.002). In athletes there was a downward trend in salivary IgA levels over the 7-month training period in both the pre-exercise (P = 0.06) and post-exercise samples (P = 0.04). There were no significant trends in salivary IgG levels over the study period in either athletes or controls. The only significant change in salivary IgM levels was an increase in detection rate in the pre-competition phase in athletes (P = 0.03). The study suggests that training of elite athletes at an intensive level over both short- and long-time frames suppresses both systemic and mucosal immunity. Protracted immune suppression linked with prolonged training may determine susceptibility to infection, particularly at times of major competitions.

Adolescent↗

Effect of competitive training on T-cell mediated immune function in Master's female athletes.

Interest in the effects of intense exercise training on immune function has grown over the past decade. Currently, data on the immunocompetence of female endurance athletes are limited and do not present a clear picture. The objective of this study was to compare the T-cell mediated immune function of female Master's athletes (41 +/- 4.3 yr) during peak training with age-matched non-athletes (42 +/- 3.6 yr) using non-specific and antigen-specific stimulation. Samples of peripheral venous blood were taken at rest for determination of total circulating T-cell number, sub-population number and CD4 + helper T-cell function. No significant difference in total circulating T-cell number or in the number of cells in each of the tested lymphocyte subpopulations was detected between athletes (n = 19) and non-athletes (n = 20). In athletes, 7.9 % of cells responding to non-specific (PMA and ionomycin) stimulation produced IL-2 versus 3.9 % of responding cells in non-athletes (p < 0.05). No statistical difference was noted between athletes and non-athletes in the percentages of antigen-responding CD4 + helper T-cells producing IL-2 (2.4 % and 2.3 %, respectively). Results of this study suggest that T-cell mediated immune function may not be compromised in female Master's athletes during periods of competitive training.

Adult↗

Helminth infections affect host immune responses to viral infections and vaccines.

Helminths are highly prevalent in many regions of the world. Due to the chronic nature of most helminth infections, these parasites are proficient immunomodulators of their hosts. This modulation often leads to skewed or even impaired immune responses against unrelated antigens, such as viruses and vaccines, which can be both beneficial and detrimental for the host. The extent of these effects and the impact on the outcomes of viral infection depends on a variety of factors including timing and tropism of both infections, pathological mechanisms, genetic background, and environmental factors. In this review, we dissect these complex interactions between virus and helminths in the context of coinfection and the impact of helminth infection on antiviral vaccine efficacy. We characterize the key contributing mechanisms that have been defined in preclinical models and human trials and describe the immune actors involved in the modulation of the antiviral and vaccine immune response by helminths. Finally, we address the limitations of our current understanding of helminth-virus interactions.

Helminthiasis↗

Alterations of cellular immune response during intensive training of event horses.

During strenuous exercise of horses that are prepared for international Three-Day-Events a significant decrease in the in vitro killing rate of phagocytosed yeast cells by the blood granulocytes has been observed. Other immunological parameters, such as the phorbolmyristate dependent chemiluminescence in granulocytes and the mitogenic stimulation of blood lymphocytes, remained unchanged.

Animals↗

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.

Adult↗

Immune and hormonal changes following intense military training.

This study was designed to determine whether the immune and hormonal systems were affected by a 5-day military course following 3 weeks of combat training in a population of 26 male soldiers (mean age, 21 +/- 2 years). The combination of continuous heavy physical activity and sleep deprivation led to energy deficiency. At the beginning of the training program and immediately after the combat course, saliva samples were assayed for secretory immunoglobulin A and plasma samples were assayed for interleukin-6, dehydroepiandrosterone sulfate, prolactin, catecholamines, glucocorticoids, and testosterone. Secretory immunoglobulin A was lower and circulating interleukin-6 was increased by the end of the course, which was attributed to sympathoadrenergic stimulation. Dehydroepiandrosterone sulfate, prolactin, and testosterone levels fell significantly. These results suggest that prolonged and repeated exercise such as that encountered in a military training program induces immune impairment via a decrease in mucosal immunity and a release of interleukin-6 into the circulation. The impaired secretion of dehydroepiandrosterone sulfate and prolactin, two immunomodulatory hormones, was thought to be a response to the chronic stressors. Lowered testosterone reflects a general decrease in steroid synthesis as a consequence of the physical and psychological strain.

Adult↗