How health-related messages are framed can impact their effectiveness in promoting behaviors, and messages framed in terms of gains have been shown to be more effective among older adults. Recent findings have suggested that the affective response to framed messages can contribute to these effects. However, the impact of demands associated with psycholinguistic processing for different frames is not well understood. In this study, exercise-related messages were gain or loss framed and with a focus on either desirable or undesirable outcomes. Participants read these messages while their eye movements were monitored and then provided affective ratings. Older adults reacted less negatively than younger adults to loss-framed messages and messages focusing on undesirable outcomes. Eye-movement measures indicated both younger and older adults had difficulty processing the most complex messages (loss-framed messages focused on avoiding desirable outcomes). When gain-framed messages were easily processed, they engendered more positive affect, which in turn, was related to better recall. These results suggest that affective and cognitive mechanisms are interdependent in comprehension of framed messages for younger and older adults. An implication for translation to effective health communication is that simpler message framing engenders a positive reaction, which in turn supports memory for that information, regardless of age. (PsycInfo Database Record (c) 2021 APA, all rights reserved).