It is generally accepted that moderate physical activity can improve immune functions and potentially reduce the risk of developing infectious diseases and cancer. There is accumulating evidence to show that moderate physical activity can enhance the activities of T cells, natural killer cells and macrophages, cytokine productivity and serum immunoglobulin (Ig) G and salivary IgA levels. In contrast, however, exhaustive exercise causes the systemic release of immunosuppressive stress hormones and anti-inflammatory cytokines, and temporarily causes a decrease in circulating lymphocyte counts and the reduction in activities of T cells and natural killer cells and salivary IgA levels. Consequently, these negative alterations in immune function and cytokine imbalance may enhance host susceptibility to infections and promote allergic disposition. Although exercise-induced mobilization and activation of phagocytic cells such as neutrophils and monocytes can result in muscular, vascular and systemic inflammation and oxidative stress due to the production of reactive oxygen species, these deleterious responses may be attenuated by the appropriate use of antioxidants and nutritional supplements. This review presents the findings from recent studies in the field of exercise immunology, and offers some insight into how these findings may be applied in the broad realm of preventive, complementary and alternative medicine.

Objective: The purpose of this study was to compare the performance of the salivary cortisol immunoassay kits that were manufactured by DRG International, Inc., Salimetrics, LLC., and IBL Hamburg, which were widely used in neuroendocrine research. Correlations between plasma and salivary cortisol concentrations and between enzyme-linked immunosorbent assay (ELISA) and luminescence immunoassay (LIA) were investigated.
Methods: Saliva and plasma samples were collected in eight participants who took part in the study of the exercise stress testing. In total, forty salivary cortisol samples were assayed by means of the three salivary cortisol immunoassay kits. Plasma cortisol concentrations were determined by ELISA kit (IBL).
Results: Salivary cortisol concentrations measured by the three immunoassay kits were significantly and highly correlated with plasma cortisol concentrations (r ≥ .863). Scattergrams also indicated that exponential curve well explained the relationship between salivary and plasma cortisol concentrations (r ≥ .925). Salivary cortisol concentrations measured by LIA (IBL) was correlated with salivary cortisol concentrations measured by ELISA (DRG and Salimetrics: r=.943 and .985, respectively). Values of cortisol concentration measured by ELISA (DRG) were higher than those by ELISA (Salimetrics) and LIA (IBL).
Conclusion: Salivary cortisol concentrations that were measured by the three immunoassay kits reflected the variations of plasma cortisol concentration. Differences in immunoassay methods (ELISA and LIA) did not influence the values of cortisol concentration. These findings indicated that it is possible to assess stress by measuring salivary cortisol without the need for blood sampling.

The discovery of microRNAs (miRNAs) and following studies reporting that miRNAs are stably present in the circulation, paved the way for possible use of miRNAs as biomarkers. Identification of circulating miRNAs that are functional upon delivery to the recipient cells, suggests miRNAs play roles in cell-to-cell communication as well as hormones and cytokines. This review provides a basic understanding of miRNAs and the current understanding of circulating miRNA as biomarkers and focuses on their putative roles and regulation under stressed conditions including physical exercise.

It has been well known that protein level is estimated by the expression level of its mRNA. However, it is also argued that correlation between mRNA abundance and protein levels is weaker than previously thought. Recently a newly developed technique called ribosome profiling has drawn attention as a drastic countermeasure to improve the weak correlation. Here it is discussed that weak association of protein and mRNA levels seen in genome-wide analysis of gene expression such as microarray is attributable to post-transcriptional regulation including translational inhibition. This review further discusses how these issues are resolved by ribosome profiling and also addresses a possibility of biomarker discovery derived from this technique.

We performed this study to evaluate the chronic effect of training on neutrophil functions in humans. Twenty-six university students (14 males and 12 females) with a mean age of 19.1±0.8 years were divided into the athlete group and the control group based on answers given to a written questionnaire. The capacity of circulating neutrophils to ingest bacteria (phagocytosis) and to produce superoxide (nitroblue tetrazolium reduction) was measured under resting conditions in the absence of training activities. In addition, we measured hematological and serum biochemical parameters. The present analyses revealed that the frequency of subjective symptoms concerning susceptibility to infections (sum of males and females) was higher in the athlete group than in the control group (p<0.05). In the investigation of males, hemoglobin and serum protein levels of the athlete group were lower than that of the control group (p<0.01, p<0.05, respectively). Although total and differential leukocyte counts, and phagocytic activity of neutrophils were not significantly different between the groups, superoxide productivity of neutrophils in the male athlete group was higher than that in the control group (p<0.05). Since significant differences were observed in hemoglobin and serum protein levels in the male athletes, the training is considered to have been intense. An increase was noted in the neutrophil superoxide production along with these changes, but no significant difference was observed in the phagocytic activity. Therefore, there is the possibility of superoxide overproduction, which may lead to tissue damage.
Neutrophils ; Training ; lower case pea ; athlete ; Superoxides

The present study was conducted to investigate the effect of acid-base disturbance on blood lactate concentration (bLA) and OBLA (Onset of Blood Lactate Accumulation) during an incremental bicycle test.
Nine healthy male subjects underwent the incremental test at 60 min after the oral administration of NH₄Cl (acidotic-treatment ; Acid), NaHCO₃ (alkalotic-treatment ; Alk) and NaCI (control ; Cont) at 1.87 mM⋅kg^-1body weight. Exercise was started at a load of 80W, which was subsequently increased by 10W every minute until exhaustion. During exercise, O²intake (VO²), ventilatory volume (VE) and heart rate (HR) were monitored continuously. Venous blood samples were obtained before administration and every 2 min during exercise.
No change could be detected in resting VO₂, VE and HR following oral administration of NH₄Cl, NaHCO₃and/or NaCl. At 60 min after oral administration venous blood pH (_vpH) and bicarbonate ion concentration (_v [HCO₃^-] ) were significantly lower in Acid (7.265±0.033; p <0.001, 23.6±1.8 mM⋅1^-1; p<0.01) ; and significantly higher in Alk (7.370±0.045 ; p<0.01, 29.7±1.6 mM⋅1^-1; p<0.01) compared to Cont (7.318±0.041, 26.6±2.1 mM⋅1^-1) . Changes in VO₂, VE and HR during exercise were essentially the same in all cases. No differences were observed in exercise time. During exercise, vpH and_v [HCO₃^-] gradually decreased, but remained significantly lower in Acid and higher in Alk compared to Cont. Blood lactate concentration (bLA) increased during exercise. Peak values were observed at exhaustion, but it was lower in Acid (8.03±1.18mM⋅1^-1) and higher in Alk (10.73±1.48) compared to Cont (9.49±1.79) in all subjects. The Onset of Blood Lactate Accumulation (OBLA) was determined for each subject. OBLA was significantly higher in Acid (71.9±9.1%VO₂max) than Cont (62.5±9.9%VO₂max) and Alk (62.2±8.0%VO₂max) .
Changes in acid-base balance were found to cause differences in bLA responses to the same exercise load and possibly change OBLA. Care must be taken when using OBLA or LT as an index of aerobic capacity in some patients with acid-bace disorders; hemodialitic, obese or diabetic patient.

The existing adoptive criterion for VO₂max was created for physically fit subjects who were soldiers and/or sportsmen. However, VO₂max is widely used at present as one of the health-related physical fitness determinants from children to aged persons. It might be appropriate to determine the criterion and the critical values for VO₂max in consideration of age and gender.
The present study attempted to determine the reference range and critical values of the criterion for VO₂max using the iterative truncation method. Voluntary VO₂max was measured in 548 healthy volunteers, aged 8 to 82 years, using a treadmill. The % VO₂max was calculated using the equation of %VO₂max=measured VO₂max × 100 gage-estimated VO₂max. Crude data of %VO₂max was applied to the iterative truncation method, and the reference range of %VO₂max (70-130%VO₂max) was determined. Physiological and biochemical parameters, within the values of 70-130%VO₂max, were converted to a percentage using a similar equation of %VO₂max. The value corresponding to 10% of the lower area of the distribution of each parameter was defined as the critical value, which was the minimum level to adopt as the VO₂max. Taking a single or combined application of the critical value of each parameter, the adoptive ratio of VO₂max was investigated.
The present study indicated that there was no difference between VO₂max selected by the iterative truncation method and that obtained by the existing criterion for VO₂max. The combination of the critical value of HRmax and bLAmax was recommended as a criterion of VO₂max. The reference value, critical value of VO₂max and the critical real value of each parameter were shown as a mean of every 5-year interval with the distinction of gender.

We investigated the effects of low-intensity brief exercise on lymphocyte functions and plasma cytokine concentrations. Six young sedentary women performed 30-min walking exercise (6 km/h, 50–65% HR max) per day for 3 weeks. Each subject’s peripheral blood was sampled before training, 1 week and 3 weeks after training, and analyzed for natural killer (NK) cell activity, T cell proliferation activity, granzyme B, interleukin-2 (IL-2), IL-6, IL-10, IL-12p40 and interferon.γ (IFN-γ). Lymphocyte functions did not change significantly following training, but plasma concentrations of IL-12p40 decreased significantly. These results suggest that cytokine balance towards significant Th1>Th2 is induced by low-intensity training.

The purpose of this study was to investigate moderate endurance exercise-induced changes in oxidative stress in different phases of the menstrual cycle. We used saliva samples which can be collected non-invasively. The resting oxidative stress levels determined by oxidation-reduction potential (ORP) were significantly higher in the menstrual phase than the follicular and luteal phases. The ORP significantly increased 30 minutes after exercise started and at the end of the 60 minute exercise session in the follicular phase. The menstrual cycle may affect oxidative stress levels at rest among young women, whereas moderate endurance exercise is likely to increase oxidative stress in the follicular phase.