<p>Neural oscillations comprise periodic and aperiodic components, which have been linked to cognitive functions. Changes in oscillatory activity as a function of age and musical training may related to cognitive decline and the protective effects of lifelong musical training. However, there are inconsistencies in prior studies assessing the changes in alpha oscillations with age and musical training experience, which did not consider the putative impact of the aperiodic activity. In this study, we recruited young and older musicians and non-musicians, comparing resting state alpha oscillations before and after correcting for aperiodic activity. We observed an age-related decline in alpha power in uncorrected and corrected periodic activities. Nonetheless, the protective effect of musical training on this decline was only evident in the corrected periodic activities, highlighting the importance of correcting for aperiodic activity. This was related to better performance in working memory tasks in older musicians compared with older non-musicians. Our findings provide mechanistic insights into how long-term musical training decelerates age-related working memory decline. It has implications for understanding the neuroplasticity of musical training on cognitive aging.</p>