Humans spend between one quarter and one third of their lives sleeping. Any disorder that occurs during this period is likely to impact both on sleep and on the whole 24 h bodily homeostasis. Sleep-related breathing disorders are highly prevalent in patients with cardiovascular disease. Central sleep apnoea (CSA) occurs mostly in patients with heart failure. Obstructive sleep apnoea (OSA) may occur in up to one third of the general population1 and in 71% of patients with resistant hypertension.2 Apnoeas cause intermittent hypoxia, sleep fragmentation and sympathetic hyperactivity.3 Both OSA and CSA may be due to rostral fluid displacement during sleep time.4 OSA involves a sleep-induced reduction of muscle tone, an increase in the CO₂ apnoea threshold and a narrowed pharynx predisposing to partial or total upper airway obstruction. Peripharyngeal fat and/or fluid accumulations are causes of airway narrowing.4 Men with body mass index above 30 kg/m² have a four times higher risk for OSA. OSA prevalence is likely to be increasing worldwide in parallel with the increase in obesity prevalence. A part of the cardiovascular risk of obesity may be mediated …