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| ORIGINAL ARTICLE |
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| Year : 2014 | Volume
: 1
| Issue : 3 | Page : 184-186 |
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A study of diurnal variation in peak expiratory flow rates in healthy adult female subjects in South India
Jenny Jayapal
Department of Physiology, Manikkudi Venkataraman Jayaraman Medical College and Research Hospital, Hoskote, Bangalore, Karnataka, India
| Date of Web Publication | 17-Aug-2014 |
Correspondence Address:
Jenny Jayapal
Department of Physiology, MVJ Medical College and Research Hospital, Hoskote, Bangalore - 562 114, Karnataka
India
 Source of Support: None, Conflict of Interest: None  | Check |
DOI: 10.4103/2348-3334.138893
Background: Peak Expiratory Flow Rate (PEFR) reflects the strength and condition of respiratory muscles and the degree of airflow limitation in large airways. PEFR shows hour to hour variation that follows a specific pattern in asthmatics and healthy individuals. Adequate data is not available for the diurnal variation in normal individuals who are students in professional courses and had a sedentary life style. Hence, this study was undertaken to study the diurnal variation in peak expiratory flow rates in healthy adult female subjects in South India. Materials and Methods: Peak expiratory flow rate was recorded in 50 adult healthy female students aged 18-23 years and studying in professional courses. Mini Wright's peak flow meter was used to measure the peak expiratory flow rate. PEFR were recorded at 7-8 a.m., 10-11 a.m., 1-2 p.m., 4-5 p.m., and 7-8 p.m. for two consecutive days. Results: On analysis of PEFR records of individual subjects, it was seen that there was an overall dip in the morning at 7-8 h PEFR, which increased in the daytime, peaking in the afternoon at 1-2 p.m. and eventually decreased in the night. Subjects did not show the peak PEFR values at the same time point, 10% of subjects had a rise in PEFR in the early morning, afternoon (1-2 p.m.) peak was observed in 48% subjects and evening (4-5 p.m.) peak was observed in 16% subjects. 14% subjects showed a peak in the night time (7-8 p.m.) PEFR values. Conclusion: This study provided the preliminary reference data of diurnal variation of peak expiratory flow rate in healthy adults. Since, there is a variation in the peak expiratory flow rate recorded during different time points of the day; hence, to compare the PEFR between individuals it is advisable to record the PEFR at the same time point. Keywords: Diurnal variation, peak expiratory flow rate, south Indian female
How to cite this article:
Jayapal J. A study of diurnal variation in peak expiratory flow rates in healthy adult female subjects in South India. CHRISMED J Health Res 2014;1:184-6 |
How to cite this URL:
Jayapal J. A study of diurnal variation in peak expiratory flow rates in healthy adult female subjects in South India. CHRISMED J Health Res [serial online] 2014 [cited 2020 Oct 23];1:184-6. Available from: https://www.cjhr.org/text.asp?2014/1/3/184/138893 |
| Introduction | |  |
Peak Expiratory Flow Rate (PEFR) reflects the strength and condition of respiratory muscles and the degree of airflow limitation in large airways. PEFR shows regular variation that follows a specific pattern in asthmatics and healthy individuals has been identified. Adequate data is not available for the diurnal variation in normal individuals who are students in professional courses and have a sedentary life style. Hence, this study was undertaken to study the diurnal variation in peak expiratory flow rates in healthy adult female subjects in South India.
Diurnal variation relates to the variation/fluctuation in peak expiratory flow rate which occurs during the course of each day (24 hours).
Peak expiratory flow rate is one of the pulmonary function tests that provide a quantifiable measure of lung function. It is relatively a simple and easy procedure to evaluate respiratory function when compared with pulmonary function testing. Peak expiratory flow is measurement of the movement of air into and out of the lungs during various breathing manoeuvres. [1] PEFR was measured by mini Wright's peak flow meter. All measurements were taken in standing position. The purpose of the test and procedure was explained and demonstrated in detail so as to get their complete co-operation. The procedure was repeated thrice, and the highest value of these three values was taken.
The lowest PFT values and the highest values were noted in the afternoon. Circadian changes occur in close temporal relation with body temperature, oxygen consumption, and carbon dioxide production. None of these variables could fully explain the diurnal pattern of ventilation. [2] Breathing is closely regulated by metabolic rate, which is influenced by multiple factors including activity and state of arousal as well as hormonal and autonomic nervous system inputs. Circadian oscillations in the sympathetic activity may have impact on the airway smooth muscles. They also suggested that scheduling elective surgical procedures or extubating patients with very limited lung function can be performed in accordance with the diurnal pulmonary clock.
| Aims and objectives | | |
This study was undertaken to study the diurnal variation in peak expiratory flow rates in healthy adult female subjects in South India.
| Materials and Methods | | |
The present study was conducted in the pulmonary function lab of Chettinad Medical College at Chennai, India. Fifty apparently healthy sedentary female subjects aged 18-23 years and studying in first year professional courses (MBBS, BDS, Nursing, and M. Sc.). All subjects were in proliferative phase of menstrual cycle for the sake of uniformity in terms of hormonal influence and to avoid the predominant influence of progesterone on PEFR. Mini Wright's peak flow meter was used to measure the peak expiratory flow rate. PEFR were recorded at 7-8 a.m., 10-11 a.m., 1-2 p.m., 4-5 p.m., and 7-8 p.m. for two consecutive days. Ethical clearance was obtained from institution ethical committee.
Before starting the actual study, subjects were briefed about the protocol and informed consent was obtained. Thorough history regarding suitability as per the above, inclusion and exclusion criteria was elicited. Basic clinical examination was carried out to rule out any cardiopulmonary or other illnesses.
Precautions observed, during the maneuver
It was ensured that the subject was comfortable and relaxed.
Apparatus was sterilized and cleaned properly.
Subject was trained adequately to perform different maneuvers.
Subject was instructed to hold the instrument in such a way that the hand did not obstruct the movement of the pointer.
The pointer was kept at the lower most level. Both the nostrils were clipped while blowing into the equipment.
Body mass index (BMI)
BMI was calculated from height and weight of the subject by using following formula.
BMI = weight (kg)/height (m) 2
Body surface area (BSA)
BSA was calculated by using Dubois' Formula as follows.
BSA (m 2 ) = weight (kg) 0.425 × height (cm) 0.725 × 0.007184 (Dubois 1916).
Calculation of diurnal variation
Amplitude percent mean (A%M) and Standard deviation percent mean (SD%M) was calculated, as per the following formula:
Statistical analysis
To analyze the diurnal variation of PEFR, the maximum out of the three recordings was taken as the final value.
The values at different time points were analyzed by one way analysis of variance (ANOVA). Diurnal variation was considered statistically significant with a P < 0.05 (Tukey's test).
| Results | | |
The anthropometric values of the subjects are given in [Table 1], the percentage of subjects showing peak PEFR values at different points of time is shown in [Table 2], and the actual measured values of PEFR are given in [Table 3]. On analysis of PEFR records of individual subjects, it was seen that there was an overall dip in the morning at 7-8 h PEFR, which increased in the daytime, peaking in the afternoon at 1-2 p.m., and eventually decreased in the night. Subjects did not show the peak PEFR values at the same time point; 16% of subjects had a rise in PEFR in the early morning, afternoon (1-2 p.m.) peak was observed in 22% subjects, and evening (4-5 p.m.) peak was observed in 36% subjects. Only 2% subjects showed a peak in the night time (7-8 p.m.) PEFR values [Table 2]. | Table 2: Percentage of subjects showing peak PEFR at different time points
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[Table 4] shows that BMI and PEFR have a positive correlation. PEFR was observed to increase linearly with BMI.
| Discussion | | |
In this study, diurnal variation and postural changes of healthy individuals was studied. Our results showed that PEFR values were low in the morning followed by a progressive rise peaking in the afternoon and evening and a small fall at night time.
The highest PEFR was noted around the midpoint as it has been suggested that the rhythm in the plasma cortisol may be the pulmonary clock, since the nadir of the cortisol rhythm would be compatible with delayed effects of corticosteroids on the airways.
There is also some data that suggest diurnal variation is correlated with age and is significantly higher in elderly individuals. [3],[4] Therefore, our study sample was distributed over a relatively narrow age range; within this age group we wanted to study any changes pertaining to diurnal variation. [5]
| Conclusion | | |
This study provided the preliminary reference data of diurnal variation of peak expiratory flow rate in healthy adults. Since there is a variation in the peak expiratory flow rate recorded during different time points of the day; hence, to compare the PEFR between individuals, it is advisable to record the PEFR at the same time point.
| References | | |
| 1. | Crapo R. Pulmonary function testing. N Eng J Med 1994;331:25-9. 
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| 2. | Medarov BI, Pavlov VA, Rossoff LA. Diurnal variation in human pulmonary function. Int J Clin Med 2008;1:267-73.
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| 3. | Boezen HM, Schouten JP, Postma DS, Rijcken B. Distribution of peak expiratory flow variability by age, gender and smoking habits in a random population sample aged 20-70 years. Eur Respir J 1994;7:1814-20.
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| 4. | Higgins BG, Britton JR, Chinn S, Lai K, Burney PG, Tattersfield AE. Factors affecting Peak expiratory flow variability and bronchial reactivity in a random population sample. Thorax 1993;48:899-905.
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| 5. | Goyal M, Goel P, Kumar P, Bajpai M, Verma NS, Kant S, et al. Circadian rhythm of peak expiratory flow rate in healthy north Indian men. Indian J Physiol Pharmacol 2008;52:64-8.
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[Table 1], [Table 2], [Table 3], [Table 4]
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