Archives of Environmental Health: An International Journal
ISSN: 0003-9896 (Print) (Online) Journal homepage: http://www.tandfonline.com/loi/vzeh20
Effects of Ozone and Brief Exercise on Specific Airway Conductance in Man Jun Kagawa MD & Toshio Toyama MD To cite this article: Jun Kagawa MD & Toshio Toyama MD (1975) Effects of Ozone and Brief Exercise on Specific Airway Conductance in Man, Archives of Environmental Health: An International Journal, 30:1, 36-39, DOI: 10.1080/00039896.1975.10666630 To link to this article: http://dx.doi.org/10.1080/00039896.1975.10666630
Published online: 02 May 2013.
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Date: 17 June 2016, At: 12:40
Effects of Ozone and rief Exercise on Specific Airway Conductance in Man
Downloaded by [La Trobe University] at 12:40 17 June 2016
Jun Kagawa, MD, Toshio Toyama, MD
Four normal male subjects were exposed to 0.9 ppm ozone with exercise for five minutes. Specific airway conductance (Gaw/Vtg) was increased by exercise and decreased by inhalation of ozone in most subjects, but these effects were small. Ozone inhalation with exercise resulted in a highly significant decrease of Gaw/Vtg. It would seem that a peak concentration of 0.9 ppm of ozone for five minutes produces adverse enects when the subject undertakes exercise in it.
Among the secondary pollutants produced by photochemical reactions that occur in the presence of strong sunlight and automobile emissions, ozone has been known as a toxic gas since it may irritate airways, extend its action into terminal bronchioles, and have a possible indirect effect on lung parenchyma. Although the characteristic toxic effects of ozone on man when exposed to high concentrations largely consist of respiratory irritation with the development of pulmonary edema and hemorrhage, only a few studies of pulmonary function following an exposure of ozone lower than 1 ppm have been reported. Goldsmith and NadeP reported an experiment, the result of which showed a slight but significant increase of airway resistance after one hour exposure in two subjects among four healthy male subjects at 0.1 ppm, in one each at 0.4 and 0.6 ppm, and in all four at 1.0 ppm. Bates et aP reported a significant decrease in maximum flow rate at 50% of the actual vital capacity CV max at 50% VC) in ten normal subjects after a two-hour exposure to
.L-1..
Submitted for publication May 14, 1974; accepted July 15. From the Department of Preventive Medicine and Public Health, School of Medicine, Keio University, Shinjuku-ku, Tokyo. Dr. Kagawa is now with the Department of Environmental Medicine and Occupational Health, School of Medicine, Tokai University, Bohseidai, Isehara-shi, Kanagawa-ken, Japan. Reprint requests to the Department of Environmental Medicine and Occupational Health, School of Medicine, Tokai University, Bohseidui, Isehara-shi, Kanagawa-ken, Japan (Dr. Kagawa).
36
Arch Environ Health/Vol 30, Jan 1975
0.75 ppm ozone, and markedly accentuated changes of pulmonary function when the subjects exercised intermittently during ozone exposure. Hazucha et aP showed a decrease of forced vital capacity, the forced exvolume volume at 1 second, maximum midexpiratory flow rate, and V max at 50% VC after two hours of intermittent exercise in 0.37 ppm ozone. Peak concentrations of oxidant in different places in the United States from 1964 to 1967 were recorded as 0.85 ppm in St. Louis, 0.67 ppm in Pasadena, Calif, and 0.65 ppm in Los Angeles.'; The present studies have been designed to explore the effects on normal subjects who performed physical exercise for short periods, when a peak concentration of ozone reached 0.9 ppm. MATERIAL AND METHODS The study subjects were four physically untrained adult men, accustomed to experimental procedures, who were considered healthy on the basis of medical history and present physical status. The average values of anthropometric data concerning the subjects were as follows: age, 23 years (20 to 25 years); height, 171 cm (170 to 175 cm); and weight, 59 kg (55 to 65 kg). Subject 4, the only smoker, has been smoking 15 cigarettes per day for four years. Measurements of airway resistance (Raw) and volume of thoracic gas (Vtg) were made by the whole-body pressure plethysmographic technique."'" The Raw was measured during the expiratory accelera tory phase between zero airflow (V) and 0.5 liter/sec. Functional residual capacity (FRC) and Vtg at which Raw was measured were calculated from the volume tracing and the plethysmographic determination of Vtg. Ozone/Kagawa & Toyama
ppm ozone for 5 minutes after a 5-minute base line measurement. Measurements were made during inhalation of ozone on a similar exercise schedule; the subject breathed ozone for 55 seconds of each minute during the 5-minute ozone inhalation. After a 5minute ozone inhalation, ozone generation was stopped and the concentration of ozone decreased to near zero within one minute, after which the subject breathed room air. On the fourth day, the subject inhaled 0.9 ppm ozone during a 5-minute exercise with the same load. Measurements were made during inhalation of ozone with exercise following a similar schedule for exercise or for ozone inhalation.
Exhaust
Data Analysis
Downloaded by [La Trobe University] at 12:40 17 June 2016
Exhaust ~-----'
Raw values were converted to the reciprocal, Gaw. All data were calculated as specific airway conductance (Gaw/Vtg, where Vtg was the lung volume at which Raw was measured) volumechanges in lung to allow for volume volume during the study. The experimental effect was calculated as the average percent change from base line to episode level for each subject separately. The importance of episode effects was tested by the Student ttest with consideration of control and base line data.
Ozone lamp
Fig 1.-Schema showing a subject breathing room air or ozone during exercise in a body plethysmograph. A, Heated flowmeter-shuUer-mouthpiece assembly, and B, valve.
The plethysmograph was outfitted with bicycle pedals connected via a drive shaft, through an airtight seal in the wall of the plethysmographic chamber, to an ergometer situated alongside the plethysmograph (Fig 1). Measurements of Raw and volume were made each minute and required volume seconds; the subject breathed plethysmographic air, while panting, for the 5 seconds during measurements, and room air or ozone for the remaining 55 seconds. This was accomplished by a valve activated by the subject. These measurement methods have been described volume volume in detaiU Ozone was produced by passingvolume air through a neon-tube silent arc generator. The ozone concentration was measured by the ozone meter (Mast Development Company) with a sampling inlet volume volumeclose to the subject (Fig 1).
PROCEDURE Base line levels consisted of an average of five observations of Raw and Vtg, measured consecutively once each minute beArch Environ Health/Vol 30, Jan 1975
fore an experimental condition or episode of interest. On the first day, control measurements consisted of an average of five consecutive measurements after base line measurements, but in the volume volumeof an experimental condition. On the second day, exercise was performed at a pedaling rate of 50 rpm for 5 minutes at the load of 100 kg-m/min. During the first two 5-minute recovery periods, measurements were made once each minute as in the base line and exercise periods. Therefore, during the entire 20-minute test the subject remained seated, leaning slightly forward in a typical cycling attitude, and breathing room air through the heated flow meter-shutter-mouthpiece assembly. During the remaining 20-minute recovery, five measurements of Raw and Vtg were made every 5 minutes and required about 2. minutes; the subject remained seated in his own comfortable way and breathed plethysmographic air that was ventilated by room air. On the third day~ the subject inhaled 0.9
RESULTS
Changes of Gaw/Vtg for each subject are expressed as the mean percent change compared with base line levels in Table 1. The percent changes of Gaw /Vtg and FRe for all subjects are expressed in a similar way in Fig 2. Significance levels of episodes and of the first 5-minute recovery period in comparison with base line, based on the t-test are shown in Table 1. Brief exercise resulted in a significant increase of Gaw/Vtg with the exception of subject 3. The 5-minute ozone inhala tion produced a tendency of decrease in Gaw/Vtg except for subject 3. SUbject 4 showed a gradual increase of Gaw /Vtg after ozone inhalation. A 5-minute ozone inhalation with exercise resulted in a highly significant decrease of Gaw/Vtg for all subjects. In order to evaluate the effect of episodes, the significance of difference between each of the episodes and its corresponding mean base line value, as well as the differences Ozone/Kagawa & ToyafT'a
31
Downloaded by [La Trobe University] at 12:40 17 June 2016
among the episodes was tested by the t-test (Tables 2 and 3). There was a significant difference of Gaw /Vtg during exercise and during ozone inhalation with exercise in every subject, except in subject 3. As for the first 5-minute recovery period after episode, the same t-test used for the effect of episodes was utilized. There was a significant difference between control and ozone inhalation with volume and ozone exercise, between exercise volumeand between inhalation with volume ozone and ozone inhalation with exercise. Although the variation of FRC was small during the control and ozone inhalation study, FRC increased above base line levels during the recovery period after exercise. However, concerning ozone inhalation with exercise, a decrease of FRC was noted during exercise though FRC returned toward the base line levels during recovery.
Table i.-Mean Percent Change of Gaw/Vtg
Episode
Control
Subject
1 2 3 4
During Episode
Recovery, Time in min A
5
0.2
0.3
7.7 -0.8 -3.3
3.9 1.5
5.5
3.7 6.2
2.5 5.1
20
15
10
-
5.8 0.1 3.2 6.1
1.8 10.6
25 3.0 3.0
-
1.8
3.3
-
2.3
30'""
- 2.4 0.0 0.2
Significance levels of during episode and the first 5-minute recovery period as compared with base line are based on the Student t-test. Level of significance: * .01
ISSN: 0003-9896 (Print) (Online) Journal homepage: http://www.tandfonline.com/loi/vzeh20
Effects of Ozone and Brief Exercise on Specific Airway Conductance in Man Jun Kagawa MD & Toshio Toyama MD To cite this article: Jun Kagawa MD & Toshio Toyama MD (1975) Effects of Ozone and Brief Exercise on Specific Airway Conductance in Man, Archives of Environmental Health: An International Journal, 30:1, 36-39, DOI: 10.1080/00039896.1975.10666630 To link to this article: http://dx.doi.org/10.1080/00039896.1975.10666630
Published online: 02 May 2013.
Submit your article to this journal
Article views: 1
View related articles
Citing articles: 1 View citing articles
Full Terms & Conditions of access and use can be found at http://www.tandfonline.com/action/journalInformation?journalCode=vzeh20 Download by: [La Trobe University]
Date: 17 June 2016, At: 12:40
Effects of Ozone and rief Exercise on Specific Airway Conductance in Man
Downloaded by [La Trobe University] at 12:40 17 June 2016
Jun Kagawa, MD, Toshio Toyama, MD
Four normal male subjects were exposed to 0.9 ppm ozone with exercise for five minutes. Specific airway conductance (Gaw/Vtg) was increased by exercise and decreased by inhalation of ozone in most subjects, but these effects were small. Ozone inhalation with exercise resulted in a highly significant decrease of Gaw/Vtg. It would seem that a peak concentration of 0.9 ppm of ozone for five minutes produces adverse enects when the subject undertakes exercise in it.
Among the secondary pollutants produced by photochemical reactions that occur in the presence of strong sunlight and automobile emissions, ozone has been known as a toxic gas since it may irritate airways, extend its action into terminal bronchioles, and have a possible indirect effect on lung parenchyma. Although the characteristic toxic effects of ozone on man when exposed to high concentrations largely consist of respiratory irritation with the development of pulmonary edema and hemorrhage, only a few studies of pulmonary function following an exposure of ozone lower than 1 ppm have been reported. Goldsmith and NadeP reported an experiment, the result of which showed a slight but significant increase of airway resistance after one hour exposure in two subjects among four healthy male subjects at 0.1 ppm, in one each at 0.4 and 0.6 ppm, and in all four at 1.0 ppm. Bates et aP reported a significant decrease in maximum flow rate at 50% of the actual vital capacity CV max at 50% VC) in ten normal subjects after a two-hour exposure to
.L-1..
Submitted for publication May 14, 1974; accepted July 15. From the Department of Preventive Medicine and Public Health, School of Medicine, Keio University, Shinjuku-ku, Tokyo. Dr. Kagawa is now with the Department of Environmental Medicine and Occupational Health, School of Medicine, Tokai University, Bohseidai, Isehara-shi, Kanagawa-ken, Japan. Reprint requests to the Department of Environmental Medicine and Occupational Health, School of Medicine, Tokai University, Bohseidui, Isehara-shi, Kanagawa-ken, Japan (Dr. Kagawa).
36
Arch Environ Health/Vol 30, Jan 1975
0.75 ppm ozone, and markedly accentuated changes of pulmonary function when the subjects exercised intermittently during ozone exposure. Hazucha et aP showed a decrease of forced vital capacity, the forced exvolume volume at 1 second, maximum midexpiratory flow rate, and V max at 50% VC after two hours of intermittent exercise in 0.37 ppm ozone. Peak concentrations of oxidant in different places in the United States from 1964 to 1967 were recorded as 0.85 ppm in St. Louis, 0.67 ppm in Pasadena, Calif, and 0.65 ppm in Los Angeles.'; The present studies have been designed to explore the effects on normal subjects who performed physical exercise for short periods, when a peak concentration of ozone reached 0.9 ppm. MATERIAL AND METHODS The study subjects were four physically untrained adult men, accustomed to experimental procedures, who were considered healthy on the basis of medical history and present physical status. The average values of anthropometric data concerning the subjects were as follows: age, 23 years (20 to 25 years); height, 171 cm (170 to 175 cm); and weight, 59 kg (55 to 65 kg). Subject 4, the only smoker, has been smoking 15 cigarettes per day for four years. Measurements of airway resistance (Raw) and volume of thoracic gas (Vtg) were made by the whole-body pressure plethysmographic technique."'" The Raw was measured during the expiratory accelera tory phase between zero airflow (V) and 0.5 liter/sec. Functional residual capacity (FRC) and Vtg at which Raw was measured were calculated from the volume tracing and the plethysmographic determination of Vtg. Ozone/Kagawa & Toyama
ppm ozone for 5 minutes after a 5-minute base line measurement. Measurements were made during inhalation of ozone on a similar exercise schedule; the subject breathed ozone for 55 seconds of each minute during the 5-minute ozone inhalation. After a 5minute ozone inhalation, ozone generation was stopped and the concentration of ozone decreased to near zero within one minute, after which the subject breathed room air. On the fourth day, the subject inhaled 0.9 ppm ozone during a 5-minute exercise with the same load. Measurements were made during inhalation of ozone with exercise following a similar schedule for exercise or for ozone inhalation.
Exhaust
Data Analysis
Downloaded by [La Trobe University] at 12:40 17 June 2016
Exhaust ~-----'
Raw values were converted to the reciprocal, Gaw. All data were calculated as specific airway conductance (Gaw/Vtg, where Vtg was the lung volume at which Raw was measured) volumechanges in lung to allow for volume volume during the study. The experimental effect was calculated as the average percent change from base line to episode level for each subject separately. The importance of episode effects was tested by the Student ttest with consideration of control and base line data.
Ozone lamp
Fig 1.-Schema showing a subject breathing room air or ozone during exercise in a body plethysmograph. A, Heated flowmeter-shuUer-mouthpiece assembly, and B, valve.
The plethysmograph was outfitted with bicycle pedals connected via a drive shaft, through an airtight seal in the wall of the plethysmographic chamber, to an ergometer situated alongside the plethysmograph (Fig 1). Measurements of Raw and volume were made each minute and required volume seconds; the subject breathed plethysmographic air, while panting, for the 5 seconds during measurements, and room air or ozone for the remaining 55 seconds. This was accomplished by a valve activated by the subject. These measurement methods have been described volume volume in detaiU Ozone was produced by passingvolume air through a neon-tube silent arc generator. The ozone concentration was measured by the ozone meter (Mast Development Company) with a sampling inlet volume volumeclose to the subject (Fig 1).
PROCEDURE Base line levels consisted of an average of five observations of Raw and Vtg, measured consecutively once each minute beArch Environ Health/Vol 30, Jan 1975
fore an experimental condition or episode of interest. On the first day, control measurements consisted of an average of five consecutive measurements after base line measurements, but in the volume volumeof an experimental condition. On the second day, exercise was performed at a pedaling rate of 50 rpm for 5 minutes at the load of 100 kg-m/min. During the first two 5-minute recovery periods, measurements were made once each minute as in the base line and exercise periods. Therefore, during the entire 20-minute test the subject remained seated, leaning slightly forward in a typical cycling attitude, and breathing room air through the heated flow meter-shutter-mouthpiece assembly. During the remaining 20-minute recovery, five measurements of Raw and Vtg were made every 5 minutes and required about 2. minutes; the subject remained seated in his own comfortable way and breathed plethysmographic air that was ventilated by room air. On the third day~ the subject inhaled 0.9
RESULTS
Changes of Gaw/Vtg for each subject are expressed as the mean percent change compared with base line levels in Table 1. The percent changes of Gaw /Vtg and FRe for all subjects are expressed in a similar way in Fig 2. Significance levels of episodes and of the first 5-minute recovery period in comparison with base line, based on the t-test are shown in Table 1. Brief exercise resulted in a significant increase of Gaw/Vtg with the exception of subject 3. The 5-minute ozone inhala tion produced a tendency of decrease in Gaw/Vtg except for subject 3. SUbject 4 showed a gradual increase of Gaw /Vtg after ozone inhalation. A 5-minute ozone inhalation with exercise resulted in a highly significant decrease of Gaw/Vtg for all subjects. In order to evaluate the effect of episodes, the significance of difference between each of the episodes and its corresponding mean base line value, as well as the differences Ozone/Kagawa & ToyafT'a
31
Downloaded by [La Trobe University] at 12:40 17 June 2016
among the episodes was tested by the t-test (Tables 2 and 3). There was a significant difference of Gaw /Vtg during exercise and during ozone inhalation with exercise in every subject, except in subject 3. As for the first 5-minute recovery period after episode, the same t-test used for the effect of episodes was utilized. There was a significant difference between control and ozone inhalation with volume and ozone exercise, between exercise volumeand between inhalation with volume ozone and ozone inhalation with exercise. Although the variation of FRC was small during the control and ozone inhalation study, FRC increased above base line levels during the recovery period after exercise. However, concerning ozone inhalation with exercise, a decrease of FRC was noted during exercise though FRC returned toward the base line levels during recovery.
Table i.-Mean Percent Change of Gaw/Vtg
Episode
Control
Subject
1 2 3 4
During Episode
Recovery, Time in min A
5
0.2
0.3
7.7 -0.8 -3.3
3.9 1.5
5.5
3.7 6.2
2.5 5.1
20
15
10
-
5.8 0.1 3.2 6.1
1.8 10.6
25 3.0 3.0
-
1.8
3.3
-
2.3
30'""
- 2.4 0.0 0.2
Significance levels of during episode and the first 5-minute recovery period as compared with base line are based on the Student t-test. Level of significance: * .01
