Improvements in cognition and associations with measures of aerobic fitness and muscular power following structured exercise

Objectives: Cognition, along with aerobic and muscular fitness, declines with age. Although research has shown that resistance and aerobic exercise may improve cognition, no consensus exists supporting the use of one approach over the other. The purpose of this study was to compare the effects of steady-state, moderate-intensity treadmill training (TM) and high-velocity circuit resistance training (HVCRT) on cognition, and to examine its relationships to aerobic fitness and neuromuscular power. Methods: Thirty older adults were randomly assigned to one of three groups: HVCRT, TM, or control. Exercise groups attended training 3 days/wk for 12 weeks, following a 2 week adaptation period. The NIH Cognitive Toolbox was used to assess specific components of cognition and provided an overall fluid composite score (FCS). The walking response and inhibition test (WRIT) was specifically used to assess executive function (EF) and provided an accuracy (ACC), reaction time (RT) and global score (GS). Aerobic power (AP) and maximal neuromuscular power (MP) were measured pre- and post-intervention. Relationships between variables using baseline and mean change scores were assessed. Results: Significant increases were seen from baseline in ACC (MD = 14.0, SE = 4.3, p =. 01, d = 1.49), GS (MD = 25.6, SE = 8.0, p =.01, d = 1.16), and AP (MD = 1.4, SE = 0.6, p =.046, d = 0.31) for HVCRT. RT showed a trend toward a significant decrease (MD = -0.03, SE = 0.016, p =.068, d = 0.32) for HVCRT. No significant within-group differences were detected for TM or CONT. Significant correlations were seen at baseline between AP and FCS, as well as other cognitive domains; but none were detected among change scores. Although no significant correlation was evident between MP and FCS or GS, there was a trend toward higher MP values being associated with higher FCS and GS scores. Conclusions: Our results support the use of HVCRT over TM for improving cognition in older persons, although the precise mechanisms that underlie this association remain unclear.