Thyroid disorders certainly affect sleep.Persons with hypothyroidism tend to be excessively fatigued and often sleep two or 3 hours longer than they did before developing hypothyroidism.Persons with hypothyroid also have less time in phase 4 sleep which is the most refreshing form of sleep.Hypothyroidism puts you at increased risk for developing sleep apnea.a condition that leads to excessive daytime drowsiness.Persons with excess thyroid function feels as if they have ingested excessive amounts of caffeine.they cannot fall asleep, have nightmares, wake up during the night and are fatigue during the day.