The locus of age x health-related physical fitness interactions in serial choice responding as a funct ion of task complexity: Central processing or motor function?

The extent to which health-related physical fitness (HRF) attenuates age di fferences in psychomotor speed as a function of task complexity was examine d in a sample of 48 men. Physiological measures were used to assign partici pants to fitness group (n(1_4) - = 12): young less fit (mean age = 25.83 ye ars), young fitter (mean age = 25.08 years), old less fit (mean age 71.83 y ears), old fitter (mean age = 66.75 years). A serial choice reaction time ( RT) task was used in which three conditions of two, four, or eight choices were administered. RTs for the choice and motor components of the task were recorded separately. A significant Age x HRF interaction was found in rela tion to choice RT but not motor time; older less Dt individuals underperfor med older fitter participants, and younger adults regardless of fitness lev el. This interaction remained significant having statistically controlled f or motor function, suggesting benefits to central processing. The strength of this interaction did not increase as a function of task complexity. The findings suggest an association between HRF and psychomotor speed, and supp ort the view that physically active lifestyles should be encouraged among o lder adults.