Effect of moderate alcohol upon obstructive sleep apnoea

Moderate-to-large quantities of alcohol are known to aggravate severe obstr uctive sleep apnoea (OSA), however, the reported effects of moderate alcoho l consumption upon mild-to-moderate OSA are inconsistent. Given the reporte d benefits of moderate alcohol consumption on cardiovascular mortality, rec ommendations regarding the management of patients with OSA are difficult to formulate. The aim of this study was to evaluate the effects of moderate a lcohol on sleep and breathing in subjects with mild-to-moderate OSA. Twenty-one male volunteers, who snored habitually, underwent polysomnograph y with and without 0.5 g alcohol.kg body weight (BW)(-1) consumed 90 min pr ior to sleep time, in random order. The mean blood alcohol concentration (B AC) following alcohol at the time of lights out was 0.07 g.dL(-1). The distribution amongst the various sleep stages was not significantly alt ered by alcohol. The mean apnoea/hypopnoea index rose from 7.1+/-1.9 to 9.7 +/-2.1 events.h(-1) (mean+/-SEM, p=0.017); however, there was no significan t change in the minimum arterial oxygen saturation measured by pulse oximet ry Sp,O-2, apnoea length or snoring intensity. Mean sleep cardiac frequency rose significantly from 53.9+/-1.4 to 59.9+/-1.9 beats.min(-1) (p<0.001) a nd overnight urinary noradrenalin increased from 14.9+/-2.3 to 18.8+/-2.3 n mol.mmol creatinine (p=0.061) on the alcohol night compared to the nonalcoh ol night. To conclude, modest alcohol consumption, giving a mean blood alcohol concen tration of 0.07 g.dL(-1), significantly increases both obstructive sleep ap noea frequency and mean sleep cardiac frequency.