The so-called Pickwickian syndrome is a combined syndrome of obesity-related hypoventilation and sleep apnea. It is named after Charles Dickens’s novel The Pickwick Papers, which contains an obese character who falls asleep constantly during the day.

The hypoventilation in Pickwickian syndrome results from severe mechanical respiratory limitations to chest excursion, caused by severe obesity. Sleep apnea may be from obstructive and/or central mechanisms. Obstructive sleep apnea is common among men with a collar size greater than 17 in (43 cm) and women with a collar size greater than 16 in (41 cm).