Breathing disturbances during snoring have been quantified by face mask pneumotachography and oesophageal catheters. In order to nonobtrusively investigate respiratory mechanics during nonapnoeic snoring in relation to sleep disturbances, we employed calibrated respiratory inductive plethysmography (RIP). In 10 snorers, RIP recordings were studied during nonapnoeic snoring without arousals in non-rapid eye movement (NREM) sleep, nonapnoeic snoring with repetitive arousals in NREM sleep and wakefulness. Results were compared to RIP recordings in undisturbed NREM sleep and wakefulness in seven healthy nonsnorers. Compared to wakefulness and undisturbed NREM sleep in nonsnorers, snoring was associated with predominant thoracic breathing, ribcage/abdominal asynchrony, and increased fractional inspiratory time. Preceding arousals during snoring, inspiratory flattening of time-derivatives of RIP volume signals, and marked ribcage/abdominal asynchrony indicated pronounced flow limitation. Low variation coefficients of respiratory cycle time (<10%) and tidal volume (<20%) discriminated snoring periods without arousals from snoring periods with arousals and from wakefulness periods, with a sensitivity of 100% and a specificity of 99%. Snoring periods with arousals were identified by the presence of snoring combined with high coefficients of variation of cycle time (> or =10%) and tidal volume (> or =20%), with a sensitivity of 96% and a specificity of 100%. Thus, characteristic patterns of ribcage/abdominal motion recorded by respiratory inductive plethysmography differentiated breathing in sleep disruptive snoring from simple snoring.