High-Intensity Training Reduces CD8+ T-cell Redistribution in Response to Exercise.

• Autores: Oliver C. Witard, Jos A. Bosch, James E. Turner, Arie Kies, Sarah R. Jackman, Asker E. Jeukendrup, Kevin D. Tipton
• Localización: Medicine & Science in Sports & exercise: Official Journal of the American College of Sports Medicine, ISSN 0195-9131, Vol. 44, Nº. 9, 2012, págs. 1689-1697
• Idioma: inglés
• Texto completo no disponible (Saber más ...)
• Resumen

  • AB Purpose: We examined whether exercise-induced lymphocytosis and lymphocytopenia are impaired with high-intensity training. Methods: Eight trained cyclists (V[spacing dot above]O2max = 64.2 +/- 6.5 mL[middle dot]kg-1[middle dot]min-1) undertook 1 wk of normal-intensity training and a second week of high-intensity training. On day 7 of each week, participants performed a cycling task, consisting of 120 min of submaximal 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 CD8+TL subpopulations on the basis of CD45RA and CD27 expression. Results: High-intensity training (18,577 +/- 10,984 cells per microliter x ~165 min) was associated with a smaller exercise-induced mobilization of CD8+TLs compared with normal-intensity training (28,473 +/- 16,163 cells per microliter x ~165 min, P = 0.09). The response of highly cytotoxic CD8+TLs (CD45RA+CD27-) to exercise was smaller after 1 wk of high-intensity training (3144 +/- 924 cells per microliter x ~165 min) compared with normal-intensity training (6417 +/- 2143 cells per microliter x ~165 min, P < 0.05). High-intensity training reduced postexercise CD8+TL lymphocytopenia (-436 +/- 234 cells per microliter) compared with normal-intensity training (-630 +/- 320 cells per microliter, P < 0.05). This was driven by a reduced egress of naive CD8+TLs (CD27+CD45RA+). 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 CD8+TLs were primarily responsible for the reduced mobilization of CD8+TLs, which occurred in parallel with smaller neuroendocrine responses. The reduced capacity for CD8+TLs to leave blood after exercise with high-intensity training was accounted for primarily by naive, and also, highly cytotoxic CD8+TLs. This impaired CD8+TL redistribution in athletes undertaking intensified training may imply reduced immune surveillance. (C)2012The American College of Sports Medicine