The influence of nocturnal alcohol ingestion on snoring.

Nocturnal alcohol ingestion is known to increase obstructive sleep apnea. It is assumed that snoring also increases under the influence of alcohol although only few data are available to support this hypothesis. The aim of this study was to investigate the influence of nocturnal alcohol ingestion on the properties of snoring. Twenty healthy male reported non-snorers (n = 10) and snorers (n = 10) underwent night-time polysomnography at three randomly assigned nights with a blood alcohol concentration (BAC) of 0.0, 0.5 and 0.8 per thousand, respectively. Snoring events were recorded by a room and body contact microphone simultaneously. Loudness and incidence of snoring were calculated and correlated to the total sleep time (TST), body position and sleep stages. Snorers revealed an increase of the apnea-hypopnea-index (AHI) under increasing BAC, whereas no decrease in the nocturnal SAO(2) was detected. Non-snorers had no increase in the AHI but a decrease in SAO(2). Snoring individuals revealed a dose-dependent increase of incidence (TSI) and loudness (LSI) of snoring with regard to the TST. The TSI increased by a factor of 1.6 at 0.5 per thousand BAC and by 4.2 at 0.8 per thousand BAC compared to the 0.0 per thousand- BAC-night. The LSI increased threefold at 0.5 per thousand BAC and 14-fold at 0.8 per thousand BAC. Snoring increased to a bigger extent in a supine position compared to non supine and during REM stage as well as Non REM 3/4 stage. Non-snorers did not present any effect of alcohol on the snoring properties with regard to TST, body position and sleep stage. The results indicate that nocturnal alcohol ingestion affects individuals with a reported history of snoring to a greater extent than non-snorers. Non-snorers did not turn into snorers under increasing alcohol influence. The recommendation, to avoid alcohol intake prior to sleep, gains of special clinical importance for individuals already snoring.