Sleep and the hypothalamic-pituitary-thyroid (HPT) axis show a mutual interdependence in normal physiological functioning [1]. While the interconnection between overt hypo- and hyperthyroidism and sleep disorders is well documented, there is a lack of substantiating evidence when mild thyroid failure is taken into account. Subclinical hypothyroidism (SHYPO), defined by an elevated thyroid stimulating hormone (TSH) with normal serum level of thyroid hormones, is a growing public health concern and affects up to 10 % of the general population, especially women.
