Purpose This study aimed to investigate the influence of an acute bout of moderate exercise and examine the potential lasting improvements over time in young and old adults within the same experimental paradigm over a 2-h testing period. The study was designed to assess the efficiency of selective control and the propensity to make fast impulsive reactions through the analyses of the percentage of correct responses (CAF) and the magnitude of the interference effect (delta curve) as a function of the latency of the response. Methods Twelve young (23 +/- 2 yr) and 12 old (63 +/- 2 yr) volunteers performed the Simon task while cycling (30 min of cycling at 65% of age-predicted HRmax) and after exercise cessation (post 5 min, post 35 min, and post 65 min). Results Results showed that exercise did not alter cognitive control. The benefit on reaction time performance was evident for both age groups and persisted after cessation for 15-20 min. Distributional analyses showed that younger people have a higher propensity to commit impulsive errors during exercise, which was not evident in older adults. Older adults adopted more cautious strategies, especially when the risk to commit an error was elevated. Despite the larger mean interference effect compared to younger adults, the pattern of the delta curves attests to the existence of an efficient cognitive control in older people. Conclusions This study illustrates the effectiveness of distributional analyses and supports the idea that exercise-induced facilitation on cognitive performance can be realized across the lifespan. Future investigations should explore whether accumulated bouts of acute exercise could display an aggregate cognitive benefit, which may significantly affect independent functioning in older adults.