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 VO2max) 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 VO2max 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.

High-intensity Interval training enhances mobilization/functionality of endothelial progenitor cells and depressed shedding of vascular endothelial cells undergoing hypoxia.

PURPOSE: Exercise training improves endothelium-dependent vasodilation, whereas hypoxic stress causes vascular endothelial dysfunction. Monocyte-derived endothelial progenitor cells (Mon-EPCs) contribute to vascular repair process by differentiating into endothelial cells. This study investigates how high-intensity interval (HIT) and moderate-intensity continuous (MCT) exercise training affect circulating Mon-EPC levels and EPC functionality under hypoxic condition. METHODS: Sixty healthy sedentary males were randomized to engage in either HIT (3-min intervals at 40 and 80 % VO2max for five repetitions, n = 20) or MCT (sustained 60 % VO2max, n = 20) for 30 min/day, 5 days/week for 6 weeks, or to a control group (CTL) that did not received exercise intervention (n = 20). Mon-EPC characteristics and EPC functionality under hypoxic exercise (HE, 100 W under 12 % O2) were determined before and after HIT, MCT, and CTL. RESULTS: The results demonstrated that after the intervention, the HIT group exhibited larger improvements in VO2peak, estimated peak cardiac output (QC), and estimated peak perfusions of frontal cerebral lobe (QFC) and vastus lateralis (QVL) than the MCT group. Furthermore, HIT (a) increased circulating CD14++/CD16-/CD34+/KDR+ (Mon-1 EPC) and CD14++/CD16+/CD34+/KDR+ (Mon-2 EPC) cell counts, (b) promoted the migration and tube formation of EPCs, (c) diminished the shedding of endothelial (CD34-/KDR+/phosphatidylserine+) cells, and (d) elevated plasma nitrite plus nitrate, stromal cell-derived factor-1, matrix metalloproteinase-9, and vascular endothelial growth factor-A concentrations at rest or following HE, compared to those of MCT. In addition, Mon-1 and -2 EPC counts were directly related to VO2peak and estimated peak QC, QFC, and QVL. CONCLUSIONS: HIT is superior to MCT for improving hemodynamic adaptation and Mon-EPC production. Moreover, HIT effectively enhances EPC functionality and suppresses endothelial injury undergoing hypoxia.