ABSTRACT

The periodic congestion and decongestion of the nasal venous sinuses and an alternation of airflow from one side of the nose to the other are known in literature as “nasal cycle”. It is established that nasal cycle during 24-hours registration contains from 4 to 8 time full periods, length of which varies from 0.80 h to 5.75 h. The mean length of all full periods is 2.80 ( 0.17 h. The mean length of full periods of left nostril is 3.07 h and the mean length of periods of right nostril is 2.43 h. The result suggests that there is any asymmetry in length of periods of airflow trough left and right nostrils about 40 min. The longer periods of left nostril can be connected with higher metabolic and functional activity of brain and human organism during active work.

Keywords:Nasal Cycle, Periods of Nostril, Sleep Cycle

1. Introduction

The spontaneous cyclical activities due to a nasal congestion and decongestion are known in literature as “nasal cycle”. Mirza et al. [1] find in the nasal cycle periods lengths ranging from approximately 1 to 5 hours during day. Gilbert [2] finds longer mean estimated period in nasal cycle during day with time-duration 4.5+/−1.0 hours (range 3.5 - 6.0 h). Winkler et al. [3] characterized daily nasal cycle as a chaotic ultradian rhythm with a periods ranging from 1 h 15 min to 3 h 20 minutes. In investigation of the nasal cycle during day Lenz et al. [5] measured a nasal cycle in 80% of 40 healthy individuals with a mean period of 2.5 h. Atanasov et al. [5] firstly characterized nasal cycle during night sleep as ultradian rhythms with periods that multiplied to the length of sleep cycle (1.5 h). Atanasov and coworkers [6] showed that the switch from left to right nostril’s domination airflow (and reverse) occurs only during REM phases of the night sleep. Ten years later Kimura et al. [7] received similar result.

In conection with this we try to characterize nasal cycle during 24-hour registration, using more parameters on the time.

2. Method, Subjects and Statistical Analyses

The temperature difference between the inspired and expired air of each nostril was detected by two thermistors inserting in face mask. Signal of thermistors multiplies by electronic amplifier and registers by XY-recorder. The same method was used for investigation of nasal cycle during night sleep [5] [6] .

Subjects were ten right-handed, healthy males (doctors), non-smoking, non-obese, non-snoring. The subjects aged-N1: 18 years, N2: 20 years, N3: 21 years, N4: 25 years, N5: 29 years, N6: 31 years, N7: 38 years, N8: 40 years, N9: 42 years and N10: 45 years. The subjects did not have a history of chronic rhinitis, none were on medications. Registration of nasal cycle was made from 7.0 h in the morning till 7.0 h of other day (morning). The assistants (general practitioner, physician, neurologist or otolaryngologist) catered apparatus and observed subjects. During the 24 hours record daily regime of subjects were the same: wake up and toilet at 6³⁰ - 7 h, beginning of record -7⁰⁰ h, breakfast 7³⁰ - 8⁰⁰ h, study 8⁰⁰ - 13⁰⁰ h, lunch and break (without sleep) 13⁰⁰ - 15⁰⁰ h, study 15⁰⁰ - 18⁰⁰ h, dinner and rest 18⁰⁰ - 22³⁰ h, toilet for sleep 22³⁰ - 23⁰⁰ h, sleep 23⁰⁰ - 7⁰⁰ h (next morning).

On Figure 1(a) is shown record of airflow of left and right nostril during 24 hours period. From 7⁰⁰ h to 7⁴⁵ h, from 11²⁰ h to 14⁰⁰ h, from 16²⁰ h to 18⁴⁰ h, from 24¹⁵ h to 2⁴⁰ h and from 5¹⁵ h to 7⁰⁰ h the airflow trough right nostril is higher versus airflow trough left nostril (i.e. right nostril dominated towards left nostril). From 7⁴⁵ h to 11²⁰ h, from 14⁰⁰ h to 16²⁰ h, from 18⁴⁰ h to 0¹⁵ h and from 2⁴⁰ h to 5¹⁵ h the airflow trough left nostril is higher versus airflow trough right nostril (i.e. left nostril dominated towards right nostril). Cyclic change of airflow of nostrils became simultaneously.

Relation of times, when dominated right nostril toward left and reverse (each nostril have higher airflow related to other) in this case was ranged as-Right: Left: Right: Left: Right: Left: Right: Left: Right = 0^45' h: 3^35' h: 2^40' h: 2^20' h: 2^10' h: 5^25' h: 2^25' h: 2^25' h: 1^45' h.

On Figure 1(b) is shown a scheme of time periods, during which right or left nostril dominated.

The 10 records of the nasal cycle/one record of each subject/were analyzed. From the record was found 85 time periods of the nasal cycle. Insufficient periods at the beginning and at the end of each record are excluded. We analyzed just full 65 periods and present histogram of distribution of these periods according to their duration and number of observation. It is used a computing program for Windows “Statistica”, for calculations.

3. Results

The lenght of full periods of the right and left nostrils varies from 0.80 h to 5.75 h. The mean length of all full 65 periods of the nostrils was T = 2.80 ± 0.17 h. The mean length of periods of left nostril was 3.07 h and the mean length of periods of right nostril was 2.43 h (see Table 1). On Figure 2 is composed histogram of distribution of all full 65 periods with approximative curve of normal (Gaussian) distribution. Values of parameters of Skewness and Kurtosis (0.28 and 1.14) are different from zero, which shows that periods haven't normal distribution. Shapiro-Wilk’s W-test shows with 99.99% possibility, that distribution of periods of nasal cycle can’t be approximated by a Gaussian curve.

Mean values, standard errors of mean (SEM), 95% confidence limits and standard deviation (SD) of all periods of left and right nostrils on histogram are given in Table1 The main basic maximum in distribution of periods on the histogram is about 1.75 h. In the range around basic maximum: 0.80 - 2.5 h are 43% of all measured full periods. There are 2 secondary maximums in the distribution-about 3.25 h and about 4.75 h. In the range around 3.25 h in interval of 2.5 - 3.5 h are 14% of all periods, and in the range around 4.75 h in interval 3.5 - 5.75 h are about 30% of all periods. Registered 65 full periods of left and right nostrils during day and night time have sum duration 178.45 h (100%). Full periods only of left nostril have sum duration 98.20 h (55.03% of time of all periods). Full periods only of right nostril have sum duration 80.25 h (44.97% of time of all periods).

4. Discussion

Registrated for 24 h nasal cycles contained time periods with lenght 0.80 h - 5.75 hours. The periods with similar lenght from 1 h to 5 h are more often measured in the studies of other authors during day and night [1] -[4] . The mean length of all full periods (2.80 h) during 24-hour registration is between mean length of periods 2.5 - 3.0 h in the daily nasal cycle and nasal cycle during night sleep [5] [6] .

The sum duration of all periods of left nostril during 24-hours registration is about 10% longer than sum duration of right nostril. For example: the mean length of all periods of left nostril (3.07 h) is longer than mean lenght of all periods of right nostril (2.43 h) with 0.64 h (38.4 min). But, the numbers of periods of two nostrils are nearly similar. The left nostril has 30 periods and right nostril has 33 periods. The result suggests, there is

any asymmetry in length of periods of the left and the right nostrils. In earlier investigations of Atanasov [8] over 120 voluntaries, a higher air-flow trough left nostril over right nostril is observed in 72% of all students during daytime. The longer length of periods of the left nostril can be connected with domination function of left hemisphere of the brain, during active work [9] .

It is known, that in left hemisphere are located humane speech functions, understanding of acoustic and visual information, control of the right hand and others. Werntz et al. [10] demonsrtated by integration EEG amplitudes, that in ultradian rhythm of alternating cerebral dominance exist in humans. This rhythm is tightly coupled with the nasal cycle, since the lateralization correlates with shifts in airflow through the left and right nostrils.

References