Affective reactivity to a single bout of high-intensity interval training in schizophrenia: a randomized controlled trial

Abstract Background and Hypothesis Affective disturbances are a core feature of schizophrenia, yet patients’ capacity to experience momentary affective shifts in real-world settings remains underexplored. Although consummatory pleasure appears preserved, studies suggest low levels of positive affect and high levels of negative affect in daily life. Physical exercise provides an ecologically valid context for probing short-term affective reactivity. This study examined whether high-intensity interval training (HIIT) elicited greater affective change than an active control condition, whether baseline symptom levels were associated with affective state, and whether baseline symptoms moderated affective reactivity. Study Design In a randomized controlled trial, 69 outpatients with schizophrenia were randomized to a 12-week intervention involving either supervised HIIT or an active control condition involving low-intensity, interactive video gaming. Affective state was assessed immediately before and after the 12th session using the Positive and Negative Affect Schedule (PANAS). Depressive (CDSS), negative symptoms (PANSS-N), and apathy (AES) were measured at baseline. Linear mixed-effects models tested Group×Time effects. Study Results HIIT did not produce significantly greater changes in positive or negative affect than the active control. Across interventions, participants showed increases in positive affect and decreases in negative affect. Higher baseline symptom levels were associated with lower pre-session positive affect. Exploratory analyses indicated that participants with more severe negative symptoms showed greater positive affective gains following HIIT. Conclusions A single session of structured activity, regardless of intensity, was associated with small but measurable affective improvements. These findings highlight the value of accessible activity-based interventions for enhancing affective well-being in schizophrenia.