Effects of normoxic and hypoxic exercise regimens on lymphocyte apoptosis induced by oxidative stress in sedentary males

Purpose: Oxidative stress-induced lymphocyte apoptosis is linked to hypoxemic individuals suffering from cardiopulmonary disorders or exposed to hypoxic environments. What kind of the exercise strategy under hypoxic condition improves exercise performance and simultaneously minimizes lymphocyte dysfunction caused by oxidative stress has not yet been established. This study elucidates how various exercises regimens with/without hypoxia affect lymphocyte apoptosis induced by oxidative stress. Methods: A total of 60 sedentary males were randomly divided into five groups. Each group (n = 12) received one of the five interventions: hypoxic-absolute exercise (HAT, 50%W_max under 15%O₂), hypoxic-relative exercise (HRT, 50% heart rate reserve under 15%O₂), normoxic exercise (NT, 50%W_max under 21%O₂), hypoxic control (HC, resting under 15%O₂), or normoxic control (NC, resting under 21%O₂) for 30 min/day, 5 days/week for 4 weeks. Results: Before the intervention, the graded exercise test (GXT, progressive exercise up to VO_2max) decreased the surface thiol level on lymphocytes and subsequently augmented the extents of H₂O₂-induced mitochondria transmembrane potential (MTP) diminishing, caspase 3/8/9 activations, and phosphotidyl serine (PS) exposure in lymphocytes. However, 4 weeks of NT, HRT, or HAT reduced the extents of surface thiol decreasing on lymphocytes and H₂O₂-induced MTP diminishing, caspase 3/8/9 activations, and PS exposure in lymphocytes following GXT. Moreover, the HAT group exhibited greater improvements in pulmonary ventilation and VO_2max than either NT or HRT group did. Conclusions: Exercise training with/without hypoxic exposure effectively alleviates lymphocyte apoptosis induced by oxidative stress following strenuous exercise. However, the HAT is superior to the NT or HRT for enhancing aerobic capacity.