To assess the effect of stress on serum cortisol level and CD4 cell count in young male postgraduate students at Igbinedion University, a cross sectional laboratory based analysis survey was adopted for this study. A total of 104 male volunteer postgraduate students (age 22 + 7.0 years, body mass index 26 + 0.5 kg/m 2) were randomly recruited. Total white blood cell (TWBC) was determined using the Sysmex® Automated Hematology Analyzer. CD4 cell count was estimated using Partec cyflow counter. Serum cortisol level was determined by enzyme-linked immunosorbent assay (ELISA) technique. It was observed that there was a significant (P < 0.05) increase in the serum cortisol level at stage A (1 st day of the semester) when compared with stage B (midway in the semester) and C (morning of the examination), while there was significant (P < 0.05) decrease in the TWBC count and CD4 cell count at A stage when compared with stage B and C. It was observed that academic stress was inhibitory of the proliferation of CD4 cells with the elevation of serum cortisol as a possible mediator.

Cortisol is a steroid hormone produced by the zona fasciculate of the adrenal cortex in response to stress, whereas interleukin-10 is an important immunoregulatory cytokine which increases with exercise. Cortisol most often is viewed as having a counter-productive role in exercise. Therefore, the objective of this study was to establish the critical role of cortisol during exercise. Moreover, the immunoregulatory role of interleukin-10 in limiting host immune response to stress was also investigated. The longitudinal study randomly selected twenty-five young apparently healthy students from the Faculty of Health Sciences and Technology, Nnamdi Azikiwe University, Nnewi Campus, aged 24.3 ± 3 years. The participating male undergraduate students were placed under resting and relaxed conditions for 48 hours prior to the test. Their blood pressures and pulse rates were taken and fasting blood sugar determined as a prerequisite screening before enlisting in the study. The subjects took part in an endurance race using the Bruce treadmill protocol for sub-maximal exercise for a maximum of 21 minutes. The target heart rate on the treadmill was 60 -80 percent of the heart rate reserve. Blood samples were collected from the participants before commencement of the study, at 1 hour, 4 hours and 24 hours post exercise. Serum cortisol (nmol/L), troponin I (ng/ml), creatine kinase MM (ng/ml) was determined using enzyme-linked immunosorbent assay methods. Interleukin-10 genes expression patterns were detected using reverse transcriptase polymerase chain reaction method. There was a significant increase in cortisol, troponin and creatine kinase MM level at 1 hour post exhaustive exercise when compared with pre-exercise stage (F = 6.032, P = 0.000), (F = 4.551, P = 0.000) and (F = 10.282, P = 0.000) respectively. The expression patterns of interleukin-10 genes were up-regulated at 4 hours post exercise and sustained till 24 hours post exercise (χ² = 50, P = 0.000). Post exercise stress activates the release of cortisol, and interleukin-10 genes to reinstate homeostasis through modulation of the immune response.