A 15-Minute Abdominal Breathing Exercise Promotes Nap in Undergraduates: Instrumental Study Findings

The study purpose: Tovalidate by polysomnography (PSG) tools the efficacy of deep abdominal breathing(AB) as a technique improving daytime nap in healthy subjects. Materials and methods: 43 healthysubjects participated in the study, of whom 22 were included intointervention group and 21 into control group. In the interventiongroup, nap PSGs were recorded for 30 min after performing AB for15 minutes. In the control group, similar PSGs were recorded after15 min of wakefulness. To assess the nap quality, standard sleepcharacteristics (latency, etc.) were determined from the subjects’hypnograms. In the intervention group total sleep time was significantlylonger and activation index was significantly lower than in controlgroup, while sleep latency did not differ significantly. In addition,the electroencephalogram (EEG) spectrum power ratio in alpha (8–13Hz) and theta (4–8 Hz) frequency bands was analyzed. Linear regressionmodel of alpha/theta power ratio time series was constructed withinthe framework of statistical analysis. It was concluded based oncomparison of coefficients of this model along with the time domainsleep characteristics, that AB exercise preceding daytime nap activatesphysiological mechanisms accelerating fall–asleep process and makingsleep more stable. This finding may be useful in the developmentof non-invasive approaches to insomnia treatment.