Abstract
Background: Sleep - A complex amalgam of behavioral and electrophysiological process is maintained by organized interaction between neurons, neural circuits, and neurotransmitters. Hypothyroidism is the inadequate secretion of thyroid hormones by the thyroid gland. Hypothyroidism, the 2nd common endocrine disorder, is often accompanied by complaints of daytime fatigue. This chronic fatigue should be managed as it may result in impaired attention with adverse consequences in the classroom, workplace, not to forget the highways.

Aims and Objectives: The primary focus of the present study is to evaluate sleep cycle in newly diagnosed overt hypothyroid patients to investigate if this fatigue is the consequence of sleep disorder.

Materials and Method: A total of 30 hypothyroid patients of both sexes underwent polysomnography to assess sleep based on bioelectric potentials - electroencephalogram, electromyogram, and electrooculogram. The results were compared with age- and sex-matched euthyroid controls.

Results: Hypothyroid patients showed significant changes in sleep stages when compared with normal euthyroid controls. Although their total sleep time was not significantly altered, Stage I and Stage II sleep was significantly increased (P < 0.001) while deep sleep and rapid eye movement sleep were reduced.

Conclusion: This research proves that early diagnosis of hypothyroidism and management guarantees an improvement in sleep quality and productivity in life.

Key words: Hypothyroid; Polysomnography; Sleep Stages