5 - (SYM 101) Effects of a Brief Bright Light Manipulation on Fatigue, Attention, and Sleep in a Sample of Adult Females with Non-underweight Binge-spectrum Eating Disorders

Daily (24-hour) physiological and behavioral processes - circadian rhythms – are maintained centrally by the superchiasmatic nucleus of the hypothalamus and synchronized by external inputs, primarily dietary behavior and light exposure. Disruptions to these rhythms are causally implicated in various psychopathology, including binge-spectrum eating disorders (ED). Moreover, those with binge-spectrum EDs report greater frequency of sleep disturbances than controls. Bright light therapy can re-entrain the circadian system and appears efficacious in the treatment of binge eating. However, the effect of bright light therapy on sleep among individuals with binge-spectrum EDs is under-researched.
 

The present study examined the effect of brief bright light manipulation in a sample of non-underweight adult females diagnosed with binge-spectrum EDs (N=31). A within-subjects, randomized crossover design was used. Following a two-day baseline, participants were randomized to 10 days of early-morning bright light (10,000 lux) or normal light exposure (500 lux) delivered using a therapy lamp; after 10 days, they switched lamp intensity conditions. A wrist worn Actiwatch Spectrum PRO® was used to estimate sleep onset latency, total sleep time, and sleep efficiency. Participants self-reported levels of attentiveness, fatigue, and indices of sleep (i.e., onset, duration, quality) using the PANAS and PSQI.
 

Self-report measures indicated that exposure to bright and normal light reduced fatigue but did not alter attentiveness. Additionally, participants reported shorter sleep duration following exposure to bright light. Although no differences between light conditions were observed, results indicated that individuals may underestimate sleep duration during use of bright light compared to objective indices. It may be that behavior changes (i.e., early wake time) required to administer morning bright light lead individuals to underestimate their sleep.
 

Actigraphy suggests that light manipulation may increase time spent asleep after onset while decreasing percent time spent awake, and future studies should examine the effects of an extended trial among those with binge-spectrum EDs. Moreover, because self-report estimates of sleep may be challenging, and objective measures are not without error (e.g., inaccuracies discerning inactivity from sleep), future studies should collect both objective (e.g., actigraphy) and self-reported data (e.g., PSQI and sleep diary), as this may improve data quality and subsequent conclusions.