Immunologic, Anti-Inflammatory, and Anti-Muscle Damage Profile of Supplemented Vitamin D3 in Healthy Adults on Strenuous Endurance Exercise

Reportedly, strenuous endurance exercise can depress the immune system and induce inflammation and muscle damage. Therefore, this double-blinded, matched-pair study aimed to investigate the impact of vitamin D₃ supplementation on immune response (leukocyte, neutrophil, lymphocyte, CD4⁺, CD8⁺, CD19⁺, and CD56⁺ counts), inflammatory profile (TNF-α and IL-6), muscle damage (CK and LDH levels), as well as aerobic capacity after strenuous endurance exercise in 18 healthy men taking 5000 IU of vitamin D₃ (n = 9) or placebo (n = 9) daily for 4 weeks. Total and differential blood leukocyte counts, levels of cytokines, and muscle damage biomarkers were determined before, immediately after, and 2, 4, and 24 h after exercise. The IL-6, CK, and LDH levels were significantly lower in vitamin D₃ group at 2, 4, and 24 h post exercise (p < 0.05). Maximal and average heart rates during exercise were also significantly lower (p < 0.05). In the vitamin D₃ group, the CD4⁺/CD8⁺ ratio after 4 weeks of supplementation was only significantly lower at post-0 than at baseline and significantly higher at post-2 than at baseline and post-0 (all p < 0.05). Taken together, 5000 IU of daily vitamin D₃ supplementation for 4 weeks exhibited positive effects in terms of increased blood 25(OH)D levels, CD4⁺/CD8⁺ ratio (immune response), and aerobic capacity while inhibiting inflammatory cytokines and CK and LDH (muscle damage) in people performing strenuous endurance exercise.

Cardiometabolic determinants of cardiorespiratory fitness at rest, during exercise and post-exercise periods

We aimed to assess the relationship between cardiorepiratory fitness (CRF) and cardiometabolic parameters among young Nigerian adults. 100 young adults (50 males, 50 females) aged 20-30 years, selected from College of Health Sciences, Nnamdi Azikiwe University, Nigeria, participated in the study. Subjects’ demographic data and medical information were obtained through the use of structured pre-exercise health and lifestyle screening questionnaire, physical examination and morphometric measurements. Exercise test was carried out using a mechanically braked magnetic ergometer bicycle at an incremental workload of 30 W every 2 min until the subject reached a volitional exhaustion. Blood pressure (BP) and heart rate (HR) were measured at rest, during exercise and at post-exercise periods. Data indicated a significantly (Ρ<0.05) lower resting HR and rate pressure product (RPP), but higher targeted HR reserve, %RPP increase, peak oxygen pulse, cardiac output, exercise duration and work rate compared with the intermediate and unfit groups in both sexes. Age and BMI adjusted correlation test also indicated significant associations between peak oxygen consumption (VO2) and resting HR, resting RPP, targeted HR reserve, oxygen pulse, cardiac output, % RPP increase, actual HR reserve, exercise duration, and work rate. In contrast, resting BP, resting pulse pressure, peak systolic blood pressure (SBP), peak HR, percentage maximum HR, SBP recovery and HR recovery did not correlate with peak VO2. The present findings suggest that a multiple approach involving both metabolic and cardiovascular interventions might be appropriate when implementing strategies to enhance CRF and improve general well-being.