title: Effects of regular exercise on lymphocyte subsets and CD62L after psychological vs. physical stress.
abstract: OBJECTIVE
  To examine the effects of regular physical activity on lymphocyte responses to a speech stressor and an exercise challenge.
  
  
  METHODS
  We assessed lymphocyte subsets and CD62L expression pre, immediately after and 15 min after a speech task vs. exercise in 24 high vs. 24 low physically active subjects. Catecholamine levels were determined by radioenzymatic assay, and enumeration of cells was assessed by flow cytometry.
  
  
  RESULTS
  Both tasks induced significant increases in plasma epinephrine (EPI; P<.05) and norepinephrine (NE; P<.001) levels. Similarly, both tasks led to increases in the numbers of lymphocyte subsets (P<.05). Physically active individuals showed attenuated responses to the speech stressor in numbers of CD62L(+), CD45RA(+), CD45RO(+) CD8(+), CD45RO(+) T(H) and CD62L(-) natural killer (NK) cells (P's<.05). In contrast, physical activity level had no significant effect on lymphocyte subsets or CD62L expression in response to exercise.
  
  
  CONCLUSIONS
  The findings suggest that physical fitness affects immune responses to a psychological but not a physical stressor. It is an interesting but open question whether attenuated lymphocyte trafficking responses to stress in regular exercisers might have clinical implications regarding host defense by the immune system.
authors.affiliation: Department of Psychiatry, University of California, 9500 Gilman Drive, La Jolla, San Diego, CA, USA. s1hong@ucsd.edu
authors.forename: Suzi
authors.initials: S
authors.lastname: Hong
authors.forename: Noha H
authors.initials: NH
authors.lastname: Farag
authors.forename: Richard A
authors.initials: RA
authors.lastname: Nelesen
authors.forename: Michael G
authors.initials: MG
authors.lastname: Ziegler
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Mills
mesh_terms: D000328:Adult; D016827:CD8 Antigens / Q000276:immunology; D002395:Catecholamines / Q000097:blood; D004837:Epinephrine / Q000097:blood; D015444:Exercise; D005260:Female; D005434:Flow Cytometry; D006304:Health Status; D006801:Humans; D007694:Killer Cells, Natural / Q000276:immunology; D019041:L-Selectin / Q000276:immunology*; D007899:Leisure Activities; D017493:Leukocyte Common Antigens / Q000276:immunology; D008016:Life Change Events; D016131:Lymphocyte Subsets / Q000276:immunology; D008297:Male; D008568:Memory / Q000502:physiology*; D008875:Middle Aged; D009638:Norepinephrine / Q000097:blood; D013060:Speech; D011795:Surveys and Questionnaires
chemical_list: D016827:CD8 Antigens; D002395:Catecholamines; D019041:L-Selectin; D017493:Leukocyte Common Antigens; D009638:Norepinephrine; D004837:Epinephrine