Interactions between Aerobic Exercise Volume, Academic Stress, and Immune Function

Many college students exercise individually or participate in collegiate and intramural sports in addition to fulfilling their stressful academic requirements. The combination of accumulated stress and vigorous exercise could result in an impaired immune system, prompting the onset of disease and absences in class and sports practice. Twenty-six male and female participants aged 18 to 23 were recruited for this study. Over the course of an academic semester, participants completed weekly electronic surveys documenting stress levels, aerobic exercise, and symptoms related to upper respiratory tract infections. Participants were evaluated at four different time points (Baseline, Post-Midterm Exam, Baseline Reassessment, and Post-Final Exam) for body fat percentage, cardiovascular fitness, heart rate, blood pressure, and a 10mL blood draw. Blood samples were used to measure blood glucose, cortisol, IL-6, and CD11b levels. Analysis of cortisol and IL-6 concentrations required ELISA kits for protein quantification in plasma samples. CD11b levels in peripheral blood mononuclear cell samples were measured by Western Blot analysis. There was a significant increase in blood pressure during the final exam compared to rest for systolic (p=0.005) and diastolic (p=0.004) blood pressures. There was a significant decrease in anxiety during the final exam compared to anxiety during the mid-term exam (p=0.022). The acute stress of an exam was strong enough to illicit physiologic blood pressure change, but the chronic stress throughout the semester was not intense enough did not illicit physiologic or immune responses. The volume of aerobic exercise in the vigorous workout group was not great enough to influence immune responses nor disease incidence

Effects of Varying Load Intensity on Skeletal Muscle Damage Between Two Isovolumic Resistance Exercise Bouts

International Journal of Exercise Science 15(4): 1212-1221, 2022. There are limited data comparing the efficacy of resistance loads within the hypertrophy range for promoting muscular growth, particularly when similar training volumes are utilized. The purpose of this study was to determine if two similar volume-loads, utilizing different intensities, would produce dissimilar muscular damage and inflammation. Eleven resistance-trained, college-aged males participated in this study. After testing 1RM barbell squats, participants completed two similar volume-load barbell squat sessions at two different resistance loads (67% and 85% of 1RM) on two separate visits. Venous blood samples were collected at baseline and one hour after completion of each exercise session. Plasma was isolated and analyzed for myoglobin and C-reactive protein (CRP) expression via ELISA. Plasma myoglobin expression was significantly elevated above baseline (BASE) values only after the 85% of 1RM (HHL) session (p =0.031), though the 67% (LHL) trial (p = 0.054; h2 = 0.647) was approaching significance (BASE: 1.42+.12 ng/mL; LHL: 4.65+1.13 ng/mL; HHL: 5.00+1.01 ng/mL). No changes in plasma CRP were observed. Despite attempts to equate volumes between resistances, mean total volume-load was significantly higher during the 67% of 1RM trial than during the 85% trial. Resistance loads at 85% of 1RM inflict significantly increased muscle damage over baseline values, even when significantly less total volume was lifted during the 85% trial. Individuals looking to maximize strength and hypertrophy during general training or during rehabilitation may benefit from these findings when determining the appropriate training load