[Ultradian rhythms in the nasal cycle as measured by a new method].

Various methods have been conventionally applied for studies of the nasal cycle. Most of these studies have been through either clinical observations by rhinologists or by the use of physiological apparatuses. The purposes of the present study are to develop a different and simplified technique for measuring the nasal cycle and to determine the extent to which the new technique works with actual cases. Five adult subjects were required to hold a 8 x 6 mirror horizontally under the nostrilsin and to breathe through the nose with the mouth closed. The length of time required for the exhalation vapor to condense on the mirror was measured every 15 minutes from 9 a.m. to 5 p.m. LR index scores (L-R/L+R) were calculated on the bases of left and right time, and maximum entropy method spectral analysis was used to determine the nasal cycle. The results showed that three of the subjects demonstrated significant periodicities equivalent to about three or four hour ultradian rhythms. Some of the problems with individual differences and with this new method were discussed.