Background: Population aging poses significant challenges in the context of cognitive function maintenance. This review aims to compare the effectiveness of various forms of physical activity, including aerobic, resistance, and mind–body exercise, in improving key cognitive domains, with a particular focus on the older adult population. Methods: A systematic review of recent scientific literature was conducted, focusing on meta-analyses and systematic reviews available in Google Scholar and PubMed, using keywords related to physical exercise, cognitive functions, aging, and forms of physical activity. Results: The analysis revealed that each training modality has a specific benefit profile. Mind–body exercises (e.g., Tai Chi) showed the greatest positive impact on global cognitive function in healthy seniors (Cohen’s Effect Size d = 0.48), surpassing both purely aerobic or resistance forms. Aerobic exercises strongly correlated with improved executive functions (planning, attention), while resistance training effectively supported memory and showed the potential to attenuate cognitive decline in clinical populations. Recent evidence indicates that combined (multimodal) training, especially a combination of aerobic and resistance exercises, leads to synergistic and superior benefits for executive functions, which are further enhanced by the integration of cognitive training elements. Conclusions: Physical activity represents a critical non-pharmacological intervention. Combined training, which promotes both physical endurance and cognitive coordination, appears to be the most optimal strategy for maximizing and expanding cognitive benefits. Given the persistent knowledge gaps regarding optimal protocols (dose-response relationships) and underlying mechanisms, further high-quality research investigating the synergistic effects of multimodal interventions is needed.