Twenty-five children, age range 2 to 14 years (mean age = 7), were referred to the Stanford University Sleep Disorders Clinic for various clinical symptoms, including excessive daytime somnolence, heavy nocturnal snoring, and abnormal daytime behavior. All children (10 girls and 15 boys) were polygraphically monitored during sleep. No sleep apnea syndrome or oxygen desaturation was revealed. However, each child presented significant respiratory resistive load during sleep associated with electrocardiographic R-R interval and endoesophageal pressure swings. The most laborious breathing occurred during REM sleep. Second degree atrioventricular blocks were also noted. Tonsillectomy and/or adenoidectomy was performed in every case and resulted in a complete disappearance or substantial amelioration of the reported symptoms. Objective evaluation by Multiple Sleep Latency Test and Wilkinson Addition Test confirmed the beneficial effect of surgery.