Systemic hypoxia promotes the mobilization of senescent CD8+ T lymphocytes into the peripheral blood compartment during moderate‐intensity exercise

Abstract

This study investigated how various regimens of exercise with/without hypoxia affected mobilization of T lymphocyte subsets into the peripheral blood compartment. Eighteen sedentary males randomly engaged in two normoxic exercise bouts [severe exercise (SE) (up to VO2max) and moderate‐intensity exercise (ME) (50%VO2max) while exposed to 21%O2], two hypoxic exercise bouts (ME while exposed to 12%O2 and 15%O2) and two hypoxic resting conditions (resting while exposed to 12%O2 and 15%O2) in a normobaric hypoxia chamber. Under normoxic conditions, SE, but not ME, increased the percentages of senescent (CD28− and CD57+)/activated (CD62L− and CD11a+)‐form CD8+T lymphocytes mobilized into the peripheral blood compartment. Although no significant change occurred in the distribution of various CD8+T lymphocyte subsets under resting 12%O2 or 15%O2 condition, the senescent/activated‐form CD8+T lymphocytes markedly released into the blood compartment following ME combined with 12%O2 or 15%O2 exposure. However, the distribution of CD4+T lymphocyte subsets in blood remained unchanged in response to various regimens of exercise with/without hypoxia. We conclude that the 12–15%O2 exposures promote the mobilization of senescent/activated CD8+ T lymphocytes into the peripheral blood compartment during ME.