Previous cross-sectional comparisons and short-term training studies of the elderly generally support our viewpoint. Shinkai et al. (1998) saw little difference in CD3+, CD4+, CD8+, CD16+ or CD19+

counts between aerobically active and inactive elderly non-smokers; very fit individuals showed a superior T cell proliferative response to both PHA, and pokeweed mitogen, but the mixed lymphocyte reaction was not enhanced, making it unlikely that their T cell effector function was enhanced. Likewise, Arai et al. (2006) found that in elderly men the proliferative response to PHA was enhanced by aerobic training. Nieman et al. (1993) also made a cross-sectional GSK126 research buy comparison between fit and unfit women aged 67–85 years; the highly trained individuals had a 54% advantage of lytic activity and a 56% greater T cell proliferative response to PHA, but there were no inter-group differences in lymphocyte subset counts, and a 12-week training programme did not enhance either T cell function or resting NK cell activity in the sedentary group. Woods et al. (1999) also found no significant increase of NK activity with six months of aerobic training in elderly men. A dissident report from Crist et al. (1989) noted a 33% increase

in resting NK cell activity in seven elderly subjects following 16 weeks of aerobic training. There is even less evidence of a positive response of immune parameters to resistance training (Raso et al., 2007, Flynn et al., 1999 and Kapasi et al., 2003), although McFarlin et al. (2004) did observe some increase of NK cell activity. In reviewing available reports, HKI-272 molecular weight Bruunsgaard and Pedersen (2000) concluded that physical training programmes acceptable to an elderly population are unable to bring about any major restoration of the senescent immune system. Our observations have been based on fitness scores, rather than questionnaire estimates of habitual physical activity. Although fitness scores reflect both the genetic characteristics of an individual and his Fluorouracil manufacturer or her habitual physical activity, this approach to classifying the activity habits

of the elderly avoids the problems of recent memory often encountered when using questionnaires in such populations. Our subjects were typical of most elderly people, not athletic and relatively unfit compared with some previously reported groups; as might be predicted from previous reports on the general elderly population, there was little evidence that lymphocyte counts and sub-sets, the proportion of naive and memory cells, NK cell sub-sets, co-stimulatory molecules, apoptotic markers and activation markers differed between the upper and lower halves of the fitness spectrum, whether this was assessed in terms of aerobic power or muscle strength. Furthermore, three subjects who were immunologically “at risk” had similar levels of fitness to the remainder of our subjects.