Increasingly, pulmonologists are called on to assist in the evaluation and treatment of patients with suspected sleep apnea hypopnea syndrome (SAHS). In that role, they are asked to communicate with and educate primary care providers and third-party payers, many of whom have little knowledge of sleep disorders medicine, and who seek specific and clear guidelines for screening, diagnosing, and treating the condition. Appropriate identification of high-risk patients requires a broad perspective of risk factors for SAHS in a variety of populations, knowledge of the potential health consequences of untreated SAHS (and of its variability according to individual susceptibility), as well as a healthy appreciation of the limitations of our current knowledge base. In fact, despite considerable clinical experience diagnosing and treating patients with SAHS (often producing “clinical successes” that are among the most remarkable experienced by internal medicine specialists), there is substantial controversy regarding how to best define and identify the syndrome and disagreement regarding which patients with SAHS may best respond to specific therapies. That, to a large extent, has made the management of SAHS more an art than science.

In this article, we first review some of the issues related to identifying individuals with frequent sleep-related respiratory disturbances (referred to as sleep-disordered breathing, SDB), including the limitations of using narrowly defined polysomnographic data for case finding. We then review the distributions of symptoms and physiologic measurements of SDB in the population, and their interrelationships. The epidemiologic data that address risk factors and consequences of SAHS are discussed, with recommendations regarding recognition priorities.