Immunosenescence, pre-frailty and impact of exercise in older persons.

Ageing process may result in a progressive decline in the immune response, known as immunosenescence (IS) which increases the susceptibility of elderly persons to infection, autoimmune disease, and cancer. With advancing age, naive T-cells are gradually being replaced by senescent phenotypes. Frailty is a geriatric syndrome characterized by a state of increased vulnerability at higher age. IS as been implicate in Cytomegalovirus (CMV) infection can exacerbate T-cell senescence and promote IS. However, little is known regarding the effects of CMV in mediating frailty. Physical exercise is being considered as a safe countermeasure against IS in the older persons. One hundred older women (> 65 years) were randomized to 2-3 times/weekly training for 6 weeks at either intensive strength (IST: 3x10 repetitions at 80% 1RM, n=31), strength endurance (SET: 2x30 repetitions at 40% 1RM, n=33), or flexibility (control, n=36) training. 6 weeks of SET decreased significantly the percentage and absolute blood count of senescence-prone T-cells in older women. When taking CMV into consideration, SET significantly decreased senescence-prone T-cells along with a concomitant increase in the naive T-cells in CMV-seropositives but not CMV-seronegatives. In 173 persons aged 80 to 99 years, pre-frailty does not require the CMV infection as a necessary factor for its development in the very old. In conclusion, strength endurance training has an anti-IS effect following 6 weeks of training in older women. In addition, CMV-serostatus plays a significant role in the immune adaptation in response to physical exercise. The presence of pre-frailty was independent from CMV infection in the very old. Exercise should be encouraged, particularly for the older adults with compromised immune system.