Sympathoadrenal activity and sleep: in the search for a marker of hyperarousal in insomnia

Abstract

Objective. To assess subjective and objective sleep characteristics and urinary metanephrine levels in patients with insomnia. Design and methods. We included patients with insomnia complaints and those without sleep– related complaints (control group) 18–75 years old. Subjective evaluation of the main sleep characteristics during the last month was assessed by the Pittsburgh Sleep Quality questionnaire, daytime sleepiness — by the Epworth Sleepiness Scale. For objective sleep evaluation we performed one-night polysomnography (PSG). Within 1 week after the PSG, daily urine was collected to determine the level of metaepinephrine. Results. The groups did not differ by age, mean sleep duration over the past month, number of night awakenings by the Pittsburgh Questionnaire, and level of daytime sleepiness. Sleep latency in insomnia group was 15 minutes longer than in the control group. PSG showed higher apnea-hypopnea and desaturation indices in the control group. There were no differences in daily urinary metanephrine excretion in the main and control groups. Correlation analysis showed no significant association between the metanephrine levels and the severity of somnolence and the index of periodic limb movements. Conclusions. Our analysis showed no significant differences in the daily urine metanephrine levels and the main PSG sleep characteristics among subjects with and without insomnia. Further work is required to clarify markers of insomnia and their negative health effects.