Edinburgh Napier University

  Sleep disruption and deprivation are common in contemporary society and have been linked with poor health, decreased job performance and increased life-stress. The rapid redeployment of lymphocytes between the blood and tissues is an archetypal feature of the acute stress response, but it is not known if short-term perturbations in sleep architecture affect lymphocyte redeployment. We examined the effects of a disrupted night sleep on the exercise-induced redeployment of lymphocytes and their subtypes. 10 healthy male cyclists performed 1 h of cycling at a fixed power output on an indoor cycle ergometer, following a night of undisrupted sleep (US) or a night of disrupted sleep (DS). Blood was collected before, immediately after and 1 h after exercise completion. Lymphocytes and their subtypes were enumerated using direct immunofluorescence assays and 4-colour flow cytometry. DS was associated with elevated concentrations of total lymphocytes and CD3−/CD56+ NK-cells. Although not affecting baseline levels, DS augmented the exercise-induced redeployment of CD8+ T-cells, with the naïve/early differentiated subtypes (KLRG1−/CD45RA+) being affected most. While the mobilisation of cytotoxic lymphocyte subsets (NK cells, CD8+ T-cells γδ T-cells), tended to be larger in response to exercise following DS, their enhanced egress at 1 h post-exercise was more marked. This occurred despite similar serum cortisol and catecholamine levels between the US and DS trials. NK-cells redeployed with exercise after DS retained their expression of perforin and Granzyme-B indicating that DS did not affect NK-cell ‘arming’. Our findings indicate that short-term changes in sleep architecture may ‘prime’ the immune system and cause minor enhancements in lymphocyte trafficking in response to acute dynamic exercise.