Background <p>With an aging population, identifying factors that support brain health and mitigate cognitive decline has become increasingly important. Among these, modifiable lifestyle factors such as cognitive reserve, physical activity, diet and sleep play a key role in healthy aging. However, the specific contribution of each factor and their role in the different cognitive domains remain unclear.</p> Aims &amp; methods <p>We investigated the role of four lifestyle factors -cognitive reserve, lifelong physical activity, dietary habits, and sleep duration- on executive functions and long-term memory in a sample of 204 cognitively healthy older adults. In this cross-sectional study, participants were assessed remotely through individual online sessions, including neuropsychological testing and standardized questionnaires. Confounding variables (sex, smoking, alcohol consumption, and number of chronic conditions) were controlled for in additive and moderation models, implemented through hierarchical general linear models.</p> Results <p>The results revealed differential effects across cognitive domains: lifestyle factors predicted executive functioning, while their association with long-term memory was limited. Individuals who adopted all four lifestyle behaviors exhibited executive function performance higher than 65% of the sample. Significant interactions emerged in the executive domain, indicating that the benefits of physical activity and a healthy diet were stronger among individuals with lower cognitive reserve, suggesting a compensatory rather than enhancing effect. Among all predictors, cognitive reserve explained the largest proportion of variance, followed by physical activity, diet, and sleep.</p> Discussion &amp; conclusions <p>Our findings emphasize the cumulative and interactive role of lifestyle factors in supporting cognition in aging, particularly executive functions, with differential associations between cognitive reserve and lifestyle factors.</p>