Effects of 6 months of moderate aerobic exercise training on immune function in the elderly

The purpose of this study was to determine the effects of 6 months of moder ate aerobic exercise on age-dysregulated measures of T lymphocyte and natur al killer (NK) cell number and function. Previously sedentary elderly (age = 65 +/- 0.8 years) subjects were randomly assigned to supervised 3 time/we ek exercise intervention group (EXC, n = 14) or flexibility/toning control group (FT-CON, n = 15). Fasting resting blood samples were drawn prior to a nd after the 6 month intervention. The EXC group exhibited a significant (P < 0.05) 20% increase in VO2 max: whereas the FT-CON group had a smaller no n-significant (P = 0.07) increase (9%). Immune results revealed that, in ge neral, changes in immune function in response to 6 months of exercise train ing at an average intensity of 52% heart rate reserve (HRR) were similar wh en compared to FT-CON who exercised at approximate to 21% HRR. There were n o intervention-induced changes in total white blood cell, neutrophil, lymph ocyte, monocyte, eosinophil, or basophil blood counts. Furthermore, the per centage and number of CD3(+) CD4(+) and CD8(+) T cells in the blood remaine d unchanged. There was a tendency for the percentage and number of CD4(+) a nd CD8(+) naive cells (CD45RA(+)) to increase and for CD4(+) memory cells ( CD45RO(+)) to decrease post-intervention, especially in FT-CON. Both groups exhibited a small intervention-induced increase in the T-cell proliferativ e response to mitogenic stimulation; the percentage change of which was hig her in the EXC group at several doses of Con A. Unstimulated NEC cell cytol ysis versus K562 cells tended to increase (P < 0.1) in the EXC group with l ittle change in FT-CON, We conclude that 6 months of supervised exercise tr aining can lead to nominal increases in some measures of immune function, w hile not affecting others, in previously sedentary elderly, (C) 1999 Elsevi er Science Ireland Ltd. All rights reserved.