How is sleep characterized in eating disorders? An investigation into sleep patterns, rest-activity rhythms, and physical activity

Sleep and eating patterns are deeply interconnected aspects of human functioning, both essential for physical and psychological well-being. While their bidirectional influences under physiological conditions are well documented, research on their relationship in the context of eating disorders (ED) remains sparse and fragmented. This thesis aims to address this gap by systematically examining how sleep and rest–activity rhythms (RAR) are characterized in ED, and by exploring the role of physical activity (PA) in shaping this association. The overarching objective is to provide clinicians with an additional tool to support well-being in individuals affected by, or at risk of, ED. The first study presents a systematic review and meta-analysis synthesizing current evidence on sleep and circadian rhythms in ED. The second study focuses on hospitalized ED patients, using actigraphy and subjective measures to assess sleep and its within- and between-person associations with PA. RAR were also measured to provide an objective overview of activity patterns across the week. The third study extends this approach to ED outpatients, with a matched control group, to clarify whether identified patterns are specific to ED. The fourth study investigates individuals at risk of ED, examining the within-person relationship between sleep quality and eating-related worries, as well as whether sleep impairments emerge before clinical onset. The fifth study adopts a qualitative perspective through a focus group with ED outpatients, offering insights into patients’ experiences of sleep and their views on its potential integration into treatment. Overall, the findings of this thesis highlight the clinical relevance of sleep in ED. Addressing sleep problems could help build emotional and cognitive resources while simultaneously increasing the effectiveness of treatment, ultimately contributing to improved well-being in individuals with, or vulnerable to, ED.