Does snoring intensity predict flow limitation or respiratory effort during sleep?

We tested whether snoring sound intensity could be an accurate predictor of the degree of respiratory effort or the decrease of inspiratory volume during partially obstructed breathing in sleep. Six snorers were investigated with nocturnal polygraphic monitoring including measurement of esophageal pressure (Pes), airflow (pneumotachometer and face mask, indicating tidal volume [VT]), and snoring sound intensity (SSI) measured in decibels. SSI was a poor predictor of flow limitation during snoring. Considerable between- and within-subject variance did not allow establishment of models for the interdependence between VT and SSI. The increase in peak-negative inspiratory efforts was better predicted by SSI. Individual multiple correlation analyses of Pes on SSI indicated a positive interdependence in all subjects. Calculation of ecological correlations with subject means of Pes and SSI was performed. SSI significantly predicted the level of peak-negative inspiratory effort during obstructed, noisy breathing for a given subject. Monitoring of snoring sound intensity may be a useful indicator identifying subjects performing high peak negative inspiratory efforts with obstructed, noisy breathing during sleep.