Estimation of the sleep stages by the non-restrictive air mattress sensor - relation between the change in the heart rate and sleep stages

摘要

The health condition could be determined by how deeply he or she sleep every night. Thus every one would like to monitor his sleep characteristics. But it is not popular. The expensiveness and the strong physical and mental monitoring stress by the conventional Rechtschaffen & Kales method using a polygraph prevent it to be popular. Development of sleep quality monitoring methods easy, kind and convenient to people is required. The author presented an air mattress method to measure the human bio-information by a non-restrictive manner easy and kind to patients. If we can find some quantitative relations between the bio-information acquired by the air mattress sensor and the sleep stages judged from the polygraph data, the quality of sleep can be estimated easily and kindly. In this study, we investigated the relations in the low (circadian), middle (ultradian) and high frequency ranges, respectively and found the following relations; [low frequency] The gradient of sleep stages is strongly co-related with that of heart rate. [middle frequency] The sleep stages and the heart rate have the strong co-relation. [high frequency] The Non-REM oscillation can be estimated from the heart rate fluctuation. From these results, we built a simple mathematical model from which the sleep stages can be estimated only by the heart rate data acquired from the air mattress sensor.