The objective of the present study was to compare the effect of acute exercise performed at different intensities in relation to the anaerobic threshold (AT) on abilities requiring control of executive functions or alertness in physically active elderly females. Forty-eight physically active elderly females (63.8 ± 4.6 years old) were assigned to one of four groups by drawing lots: control group without exercise or trial groups with exercise performed at 60, 90, or 110% of AT (watts) and submitted to 5 cognitive tests before and after exercise. Following cognitive pretesting, an incremental cycle ergometer test was conducted to determine AT using a fixed blood lactate concentration of 3.5 mmol/L as cutoff. Acute exercise executed at 90% of AT resulted in significant (P < 0.05, ANOVA) improvement in the performance of executive functions when compared to control in 3 of 5 tests (verbal fluency, Tower of Hanoi test (number of movements), and Trail Making test B). Exercising at 60% of AT did not improve results of any tests for executive functions, whereas exercise executed at 110% of AT only improved the performance in one of these tests (verbal fluency) compared to control. Women from all trial groups exhibited a remarkable reduction in the Simple Response Time (alertness) test (P = 0.001). Thus, physical exercise performed close to AT is more effective to improve cognitive processing of older women even if conducted acutely, and using a customized exercise prescription based on the anaerobic threshold should optimize the beneficial effects.
Aging; Alert; Anaerobic threshold; Exercise; Executive functions; Response time test