High-intensity training reduces CD8+ T Cell Redistribution in Response to Exercise.
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Colleges, School and Institutes
PURPOSE:: We examined whether exercise-induced lymphocytosis and lymphocytopenia are impaired with high-intensity training. METHODS:: Eight trained cyclists (V˙ O2 max: 64.2 ± 6.5 mL·kg·min) undertook one week of normal-, and a second week of high-intensity training. On day seven of each week, participants performed a cycling task, consisting of 120 min sub-maximal exercise followed by a 45 min time trial. Blood was collected before, during and after exercise. CD8 T lymphocytes (CD8+TLs) were identified, as well as CD8TL sub-populations on the basis of CD45RA and CD27 expression. RESULTS:: High-intensity training (18,577 ± 10,984 cells·μL× ∼165 min) was associated with a smaller exercise-induced mobilization of CD8TLs compared with normal-intensity training (28,473 ± 16,163 cells·μL× ∼165 min, p = 0.09). The response of highly cytotoxic CD8TLs (CD45RACD27-) to exercise was smaller following one week of high- (3,144 ± 924 cells·μL× ∼165 min) compared with normal-intensity training (6,417 ± 2,143 cells·μL× ∼165 min; p <0.05). High-intensity training reduced post-exercise CD8TL lymphocytopenia (-436 ± 234 cells·μL) compared to normal-intensity training (-630 ± 320 cells·μL; p <0.05). This was driven by a reduced egress of naïve CD8TLs (CD27CD45RA). High-intensity training was associated with reduced plasma epinephrine (-37%) and cortisol (-15%) responses (p <0.05). CONCLUSIONS:: High-intensity training impaired CD8+TL mobilization and egress in response to exercise. Highly cytotoxic CD8TLs were primarily responsible for the reduced mobilization of CD8TLs, which occurred in parallel with smaller neuro-endocrine responses. The reduced capacity for CD8TLs to leave blood post-exercise with high-intensity training was accounted for primarily by naïve, and also, highly cytotoxic CD8TLs. This impaired CD8TL redistribution in athletes undertaking intensified training may imply reduced immune-surveillance.
|Journal||Medicine and Science in Sports and Exercise|
|Publication status||Published - 19 Apr 2012|