THE IMPACT OF TRNS ON AFFECTIVE RESPONSES TO EXERCISE IS INFLUENCED BY SELF-REPORTED TOLERANCE Talon Perdue and Mark E. Hartman, University of Rhode Island Regular exercise significantly reduces the risk of many disorders and diseases. Nevertheless, the percentage of adults who exercise regularly continues to be low. Exercise behavior is influenced by individual differences in self-reported tolerance to exercise and by affective responses during exercise. Higher pleasure ratings during exercise correlate with increased participation, as opposed to exercise with lower ratings. Recent studies have demonstrated that non-invasive brain stimulation can modify the affective states through increasing top-down regulatory control mechanisms. PURPOSE: Determine the relationship between self-reported tolerance and affective responses when using tRNS. METHODS: In counterbalanced order, 24 participants (14F, 10 M; age: 20.8 ± 3.1y; BMI: 28.4 ± 4.1 kg·m-2) completed two conditions: self-paced cycle ergometry for 30 minutes with active tRNS of the dorsolateral prefrontal cortex (dlPFC) or sham stimulation. Participants were divided into low- and high- Tolerance groups based on a median split of their Tolerance scores (Preference for and Tolerance of the Intensity of Exercise Questionnaire). Affective valence ratings (Empirical Valence Scale; EVS) were collected each minute. RESULTS: The low tolerance group reported significantly higher EVS scores during exercise with active tRNS than sham (p <.05,np2 =.128). In contrast, EVS scores for the high tolerance group were not significantly different between conditions (p =.16,np2 =.051). Furthermore, the low tolerance group reported significantly higher EVS scores during active tRNS exercise compared to the high tolerance group(p <.05,np2 =.178). CONCLUSION: These findings indicate that tRNS of the dlPFC may be more effective in improving affective responses to exercise among individuals with lower self-reported tolerance to exercise. The Rhode Island Foundation Medical Research Grant