The Study of the Effect of Constant Intensity Level Sound of Varying Frequencies on the Blood Pressure and the Heart Rate

Transcription

1 International Journal of Pure an Applie Physics ISSN Volume 6, Number 3 (2010), pp Research Inia Publications The Stuy of the Effect of Constant Intensity Level Soun of Varying Frequencies on the Bloo Pressure an the Heart Rate Meena Laa Hea, Dept of Physics & Electronics, Inian Acaemy Degree College & Post Grauate Research Centre, Bangalore Corresponence Author Aress i: meenaslaa@reiffmail.com Abstract The souns of appropriate frequencies can be use as an effective treatment for relaxation, anxiety reuction, muscle-tension reuction, an pain management. This research work is a systematic stuy of the effect of souns of specific frequencies an at constant intensity level 70 B on systolic bloo pressure, iastolic bloo pressure an the heart rate of healthy iniviuals. 67 healthy iniviuals (35 male an 32 female), age years were expose to constant 70 B soun of frequencies 250 Hz, 500 Hz, 1kHz, 4kHz an 8kHz respectively prouce by auiometer in a soun-proof room uner expert supervision for 10 minutes for each frequency. Bloo pressure an heart rate were measure before an after the exposure of the prouction of soun of each frequency using a igital Bloo Pressure machine. It was observe that souns of ifferent frequencies at constant 70 B intensity affect the above parameters ifferently. Experiments showe that at the exposure of 70B soun at 8 khz, 64.17% subjects showe the increase an 26.86% subjects showe the ecrease in heart rate whereas 8.95% subjects i not show any change in the heart rate. It was also notice that 40.6% female subjects were foun to have increase systolic bloo pressure at frequency 8 khz an 75% female subjects were foun to have ecrease in systolic bloo pressure at frequency 500 Hz. 31.3% female subjects ha shown the increase in iastolic bloo pressure at higher frequencies of 1kHz, 4kHz an 8kHz whereas 78.1% female subjects showe ecrease in systolic bloo pressure at frequency 500Hz. The increase as well as ecrease in heart rate was foun to affect maximum number of female subjects, 66.2% at soun frequency 500 Hz at the intensity level 70B. This stuy can be use to take safety measures at places where iniviuals are expose to ifferent souns for a long perio time affecting their health aversely such as factories, places in the vicinity of

2 284 Meena Laa railway stations or Airports. It can also be use in meical technology by using souns of appropriate frequencies to treat various ailments. Introuction The use of souns of various frequencies is a recently recognize technology in which souns in the auible range is use to prouce mechanical vibrations that are applie irectly to the boy. Physics of simple soun can be escribe as a function of frequency, amplitue an phase. The technology uses speakers or transucers place within mats, mattresses, chairs, recliners, tables, or soft furniture to provie a physiologic an auitory experience. The benefits of this technology inclue pain management, anxiety relief, symptom reuction, physical therapy, an health improvement. Thus the frequency of souns to which we are expose, plays very important role in maintaining goo health. Vibrations in the auible frequency range have been use to help bring patients back to mental, physical an emotional balance in many cultures [1, 2]. Current meical technology has utilize vibration in varying egrees of intensity an frequency. Ultrasonic frequencies, above the auible range, assist with iagnoses via ultrasoun technology. Very high-frequency vibrations are use to break kiney stones into very small pieces an to treat tissue contractures. Complementary health practitioners use forms of inauible soun below 20 Hz for infrasonic vibratory treatment, such as soun waves use by chiropractors to relieve joint an muscle pain. Norwegian eucator an therapist Olav Skille experimente with low-frequency souns between 20 an 120 Hz to generate vibrations for chilren with severe physical an mental hanicaps. He evelope the first VibroAcoustic Chair (Skille, Levanger, Norway) in the late 1980s, using one pulse, sinusoial frequency as the soun source for generating vibrations blene with music for listening. [3] In the 1970s, Petri Lehikoinen, a clinical psychologist at Helsinki University, Finlan, create the physioacoustic metho base on scanning the boy with sinusoial soun between 27 an 113 Hz an specially selecte listening music. In 1985, Unite States inventor Byron Eakin release his vibroacoustic system as a relaxation tool. Soun frequencies that are input into vibroacoustic evices become mechanical vibrations felt by the boy. A significant acoustic consieration in vibroacoustic esign is how vibrations are receive an experience by patients. Important factors inclue the resonance characteristics of the vibrating surface, or vibrating membrane, an the spatial istribution of vibrations over the surface [4]. The soun stimulus may use specific frequencies with or without music. Various soun properties can be manipulate to attain specific experiences. Some instruments focus on the application of soun frequencies between 27 an 135 Hz an experimentation has inicate the resulting mechanical vibrations create strong physical responses in patients. [5, 6]. The range of Hz has been emphasize in certain vibroacoustic applications because this frequency range is known to stimulate Pacinian corpuscles, which play a key function in pain perception. [7,8,9] Most vibroacoustic moels also make use of full-frequency music at least for listening, base on benefits that have been recognize in music therapy[10,11] an to provie a more interesting experience for patients.

3 The Stuy of the Effect of Constant Intensity Level Soun 285 Soun is most often pulse in instruments at a slow rate of spee. It is believe that pulse souns create a more pleasant sensation for patients an a a relaxing element to treatment.[3] Research by Tony Wigram, associate professor at the Institute for Music an Music Therapy, Aalborg, Denmark, compare pulse soun lengths of 6, 10 an 14 secons, peak to peak, an a pure sinusoial tone. While specific frequencies an vibration processing techniques have proven to be effective, music may also hol essential value. Research has shown that live an recore music can be use in treating illness an maintaining health. Chesky, Michel, an Konraske presente the Two-Pronge Approach conceptual moel of vibroacoustics, highlighting the powerful synergy create from integration of physiologic soun vibration an psychological stimulation from music listening.[4] Vibration an music together may be more powerful than either element inepenently an may be especially useful in certain instances. An important aspect of music may be the broa range of frequencies within music.thus souns of appropriate frequencies can be use as an effective treatment for relaxation, anxiety reuction, muscle-tension reuction, an pain management. In 1918 Hye an Scalapino escribe the effects of ifferent types of music on heart rate an bloo pressure. They commente, the minor tones of music increase the pulse rate an lowere the systolic an iastolic pressures. On the other han the stirring notes of Toreaor s song increase the systolic an pulse pressure increase the pulse rate. [12] In 1920 Diserens note that music also ha an effect on respiratory timing: in general respiratory rhythm follows that of the music.[13] Since then, numerous stuies have ocumente the effects of ifferent types of music on heart rate, bloo pressure an respiratory frequency[14,15]. In aition to escribing an increase in respiratory frequency, Bernari an colleagues [16] also note an increase in heart rate an bloo pressure, with the increase again correlate to music tempo. Materials an Metho CD player Heaphone Digital bloo pressure an heart rate measuring machine. 67 healthy iniviuals (35 male an 32 female), age years were expose to constant 70 B soun of frequencies 250 Hz, 500 Hz, 1kHz, 4kHz an 8kHz respectively prouce by auiometer in a soun-proof room uner expert supervision for 10 minutes for each frequency. Proceure was explaine to them an consent was taken. Only those subjects were selecte for the experiment for whom Resting heart rate was between , resting systolic an iastolic bloo pressure were between an 60-90mm Hg, respectively. Bloo pressure an heart rate were measure before an after the exposure of the prouction of soun of each frequency. The subjects selecte for the stuy were themselves control group by exposing them to experimental conitions, without prouction of soun. The bloo pressure an heart rate were measure using a igital Bloo Pressure measuring machine.

4 286 Meena Laa Results Effect of souns of ifferent frequencies at constant intensity level 70 B on Systolic Bloo Pressure Parameter Frequency Increase in Male increase in Female ecrease in Male ecrease in Female Systolic Bloo Pressure 250 Hz Hz kHz khz kHz Effect of souns of ifferent frequencies at constant 70 B intensity level on Diastolic Bloo Pressure Parameter Frequency Increase in Male increase in Female ecrease in Male ecrease in Female Diastolic Bloo Pressure 250 Hz Hz kHz khz kHz Effect of souns of ifferent frequencies at constant 70 B intensity level on the Heart rate Parameter Frequency Increase in Male increase in Female ecrease in Male Heart Rate 250 Hz Hz kHz khz kHz ecrease in Female

5 The Stuy of the Effect of Constant Intensity Level Soun 287 Effect of soun of frequency 250 Hz at 70 B on Systolic an Diastolic Bloo Pressure an Heart Rate in terms of the percentage of the subjects Parameters Increase Decrease No Effect Systolic Bloo Pressure (F10, M13) (34.32%) (F22, M21) (64.17%) ( M1,F0) (1.49%) Diastolic (F8, M15) Bloo Pressure (34.32%) Heart Rate (F16, M17) (49.25%) (F23, M22) (67.16 %) (F16, M17) (49.25%) (F1, M2) (4.47%) (F2, M1) (4.47%) Effect of soun of frequency 500 Hz at 70 B on Systolic an Diastolic Bloo Pressure an Heart Rate in terms of the percentage of subjects Parameters Increase Decrease No Effect Systolic (F8, M12) (F24, M23) ( M0F0) Bloo Pressure (29.85%) (70.14%) (0%) Diastolic (F6, M10) Bloo Pressure (23.88%) Heart Rate (F12, M19) (46.26%) (F25, M21) (68.65 %) (F18, M14) (47.76%) (F1, M0) (1.49%) (F2, M2) (5.97%) Effect of soun of frequency 1 khz at 70 B on Systolic an Diastolic Bloo Pressure an Heart Rate in terms of the percentage of the subjects Parameters Increase Decrease No Effect Systolic (F12, M13) (F19, M22) ( M0F1) Bloo Pressure (37.31%) (61.19%) (1.49%) Diastolic (F10, M9) Bloo Pressure (28.35%) Heart Rate (F18, M16) (50.74%) (F21, M24) (67.16 %) (F16, M14) (44.77%) (F1, M2) (4.47%) (F0, M3) (4.47%)

6 288 Meena Laa Effect of soun of frequency 4 khz at 70 B on Systolic an Diastolic Bloo Pressure an Heart Rate in terms of the percentage of the subjects Parameters Increase Decrease No Effect Systolic (F12, M10) (F20, M25) ( M0F0) Bloo Pressure (32.83%) (67.16%) (0%) Diastolic (F10, M17) Bloo Pressure (40.29%) Heart Rate (F14, M16) (44.77%) (F21, M17) (56.71%) (F16, M19) (52.23%) (F1, M1) (2.98%) (F2, M0) (2.98%) Effect of soun of frequency 8 khz at 70 B on Systolic an Diastolic Bloo Pressure an Heart Rate Parameters Increase Decrease No Effect Systolic (F13, M9) (F18, M26) ( M0,F1) Bloo Pressure (32.83%) (65.67%) (1.49%) Diastolic Bloo Pressure (F10, M12) (32.83%) (F22, M19) (61.19%) (F0, M4) (5.97%) Heart Rate (F16, M27) (64.17%) (F12, M6) (26.86%) (F4, M2) (8.95%) Percentage of subjects showing increase in systolic bloo pressure, iastolic bloo pressure an heart rate when expose to the soun at constant intensity level 70B an varying frequencies e e W ^W W,Z,,,, e, &,

7 The Stuy of the Effect of Constant Intensity Level Soun 289 Percentage of subjects showing ecrease in systolic bloo pressure, iastolic bloo pressure an heart rate when expose to the soun at constant intensity level 70B an varying frequencies W e e e ^W W,Z,,,, e, &, Percentage of subjects showing no change in systolic bloo pressure, iastolic bloo pressure an heart rate when expose to the soun at constant intensity level 70B an varying frequencies W e e e e ^W W,,,,, e, &, Result an Discussion It was observe that at the exposure of 70B soun at 250 Hz, 34.32% subjects showe the increase an 64.17% subjects showe the ecrease in Systolic bloo pressure whereas 1.49% subjects i not show any change in the systolic bloo pressure. At the exposure of 70B soun at 250 Hz, 34.32% subjects showe the increase an 67.16% subjects showe the ecrease in Diastolic bloo pressure whereas 4.47% subjects i not show any change in the iastolic bloo pressure. At

8 290 Meena Laa frequency 250 Hz, 49.25% subjects showe the increase an 49.25% subjects showe the ecrease in heart rate whereas 4.47% subjects i not show any change in the heart rate. It was observe that at the exposure of 70B soun at 500 Hz, 29.85% subjects showe the increase an 70.14% subjects showe the ecrease in Systolic bloo pressure. Every subject was foun to be affecte by the exposure of the soun an showe change in systolic bloo pressure. It was also notice that at the exposure of 70B soun at 500 Hz, 23.88% subjects showe the increase an 68.65% subjects showe the ecrease in Diastolic bloo pressure whereas 1.49% subjects i not show any change in the iastolic bloo pressure. Experiments showe that at the exposure of 70B soun at 500 Hz, 46.26% subjects showe the increase an 47.76% subjects showe the ecrease in heart rate whereas 5.97% subjects i not show any change in the heart rate. At 1kHz, 37.31% subjects showe the increase an 61.19% subjects showe the ecrease in Systolic bloo pressure. 1.49% subjects i not show any change in systolic bloo pressure.it was also notice that at the exposure of 70B soun at 1 khz Hz, 28.35% subjects showe the increase an 67.16% subjects showe the ecrease in Diastolic bloo pressure whereas 4.47% subjects i not show any change in the iastolic bloo pressure. Experiments showe that at 1 khz, 50.74% subjects showe the increase an 44.77% subjects showe the ecrease in heart rate whereas 4.47% subjects i not show any change in the heart rate. At frequency of 4 khz, 32.83% subjects showe the increase an 67.16% subjects showe the ecrease in Systolic bloo pressure. Each subject was foun to be affecte by the exposure of the soun an showe change in systolic bloo pressure. It was also notice that at the exposure of 70B soun at 4 khz Hz, 40.29% subjects showe the increase an 56.71% subjects showe the ecrease in Diastolic bloo pressure whereas 2.98% subjects i not show any change in the iastolic bloo pressure.also at 4 khz, 44.77% subjects showe the increase an 52.23% subjects showe the ecrease in heart rate whereas 2.98% subjects i not show any change in the heart rate. It was observe that at the exposure of 70B soun at 8 khz, 32.83% subjects showe the increase an 65.67% subjects showe the ecrease in Systolic bloo pressure. 1.49% subjects i not show any change in systolic bloo pressure. It was also notice that at the exposure of 70B soun at 8 khz, 32.83% subjects showe the increase an 61.19% subjects showe the ecrease in Diastolic bloo pressure whereas 5.97% subjects i not show any change in the iastolic bloo pressure. Experiments showe that at the exposure of 70B soun at 8 khz, 64.17% subjects showe the increase an 26.86% subjects showe the ecrease in heart rate whereas 8.95% subjects i not show any change in the heart rate. It was also notice that 40.6% female subjects were foun to have increase systolic bloo pressure at frequency 8 khz an 75% female subjects were foun to have ecrease in systolic bloo pressure at frequency 500 Hz. 31.3% female subjects ha shown the increase in iastolic bloo pressure at higher frequencies of 1kHz, 4kHz an 8kHz whereas 78.1% female subjects showe ecrease in systolic bloo pressure at frequency 500Hz. The increase as well as ecrease in heart rate were foun to affect maximum number of female subjects, 66.2% at soun frequency 500 Hz at the intensity level

9 The Stuy of the Effect of Constant Intensity Level Soun B B. Thus ifferent soun frequencies affect the bloo pressure an heart rate ifferently. Soun has a physical an a psychological component. Physics of simple soun can be escribe as a function of frequency, amplitue an phase. The frequency components of the complex soun are known as harmonics. The way music changes bloo pressure an heart rate was investigate by several stuies with ifferent results. There are stuies showing increase heart rates as a result of stimulating music an ecrease heart rates associate with seative music [17, 18]. Other stuies ocument increase heart rate as the result of listening to seative an stimulating music[19] an Shatin [20] notes an increase in long term schizophrenics. Gerra et al [21] foun that the type of music can influence heart rate an stress-relate hormones. Specifically Techno-music seeme to prouce a significant increase in heart rate, systolic bloo pressure an stress-relate hormones. Classical music prouce no significant changes in these parameters. Psychophysiological reactions in stuents ue to exposure to a istorte soun of 400 Hz frequency, 109 b intensity an 0.5 sec uration are ocumente as follows[22]. Systolic an iastolic bloo pressure were increase 4 11 secons after the intense auitory stimulus. Afterwars bloo pressure was ecrease an reache the normal level a minute after. This stuy shows a temporarily increase bloo pressure. In 1918 Hye an Scalapino escribe the effects of ifferent types of music on heart rate an bloo pressure. They commente, the minor tones of music increase the pulse rate an lowere the systolic an iastolic pressures. On the other han the stirring notes of Toreaor s song increase the systolic an pulse pressure [an] increase the pulse rate.[23] In 1920 Diserens note that music also ha an effect on respiratory timing: in general respiratory rhythm follows that of the music.[24] Since then, numerous stuies have ocumente the effects of ifferent types of music on heart rate, bloo pressure an respiratory frequency.[25,26] In this issue of Heart, Bernari an colleagues suggest, in contrast to Hye an Scalapino, that it is not the key in which the music is set, but the unerlying tempo that is important in etermining the physiological response.[27] Bernari an colleagues [27] stuie the effect of ifferent styles an tempos of music on cariovascular an respiratory control in both musicians an non-musicians. They foun that breathing frequency was increase by musical inputs, an that this increase was proportional to the tempo of the music. They escribe 1:4 entrainment of breathing to the unerlying musical rhythm at slow tempos, an 1:8 entrainment at faster tempos, an while they suggest that at intermeiate tempos an integer ratio is not observe, this oes not preclue more complex coupling relationships from being present.[28] The correlation between musical tempo an respiratory frequency was greater in musicians than non-musicians, consistent with the earlier observation of Haas an colleagues that musicians showe a greater egree of respiratory entrainment than non-musicians.[25] It is possible that the musician s traine ear effectively resulte in a stronger input signal from the music to the respiratory oscillator than in the non-musician, resulting in the stronger correlation between tempo an respiratory rhythm.

10 292 Meena Laa In aition to escribing an increase in respiratory frequency, Bernari an colleagues [27] also note an increase in heart rate an bloo pressure, with the increase again correlate to music tempo. Okamoto et al [28] also observe the effects of frequency an intensity of soun on cochlear bloo flow using 15 guinea pigs an suggeste that there is a corresponing bloo flow area which is sensitive to specific frequency in the cochlea. Many research scientists in the worl have observe a significant rise in bloo pressure in response to noise. [29-42] Some of the scientists observe a rise only in systolic bloo pressure,while many others foun a significant increase in both systolic an iastolic bloo pressure in response to noise. Thus the exposure by souns to various frequencies can cause increase or ecrease in the systolic an iastolic bloo pressures an also in the heart rate. The efforts shoul be mae to reuce the exposure an ill effects of souns of harmful frequencies. In our stuy, the exposure to souns of various frequencies for a very short uration 10 minutes prouce a significant change in bloo pressure an heart rate. References [1] Campbell, D. Music: Physician for Times to Come. Lonon: Quest Books, [2] Pratt, R., Jones R. Music an meicine: A partnership in history. In J Arts Me, 1988; 6: [3] Skille O. Manual of vibroacoustic therapy. Levanger, Norway: ISVA Publications, [4] Chesky KS, Michel DE, & Konraske G. Developing methos an techniques for scientific an meical application of music vibration. In: Spintge R, Dron R es. Music Meicine, vol 2. St. Louis, MO: MMB Music. 1996; 2: [5] Lehikoinen, Petri. The physioacoustic metho. In: Wigram T, Dileo C, es. Music Vibration an Health, Cherry Hill, NJ: Jeffrey Books, 1997; [6] Wigram T. The evelopment of vibroacoustic therapy. In: Wigram T, Dileo C, es. Music Vibration an Health, Cherry Hill, NJ: Jeffrey Books, 1997: [7] Lunenberg T, Noremarr R, Ottoson D. Pain alleviation by vibratory stimulation. Pain 1984;20: [8] Quillian TA, Sato M. The istribution of myelin an nerve fibres from Pacinian Corpuscles. J Physiol, 1955;129: [9] Hubbar SJ. A stuy of rapi mechanical events in a mechanoreceptor. J Physiol 1958;141: [10] Dileo C. The context of music an meicine. In: Wigram T, Dileo C, es. Music Vibration an Health. Cherry Hill, NJ: Jeffrey Books, 1997: [11] Welin C, Eagle C. An historical overview of music meicine, In: Applications of Music Meicine, Washington, DC: National Association for Music Therapy 1991: 7-27.

11 The Stuy of the Effect of Constant Intensity Level Soun 293 [12] Hye IH, Scalapino W. The influence of music upon electrocariograms an bloo pressure. Am J Physiol1918; 46:35 8. [13] Diserens CM. Reaction to musical stimuli. Psych Bull1920;20: [14] Haas F, Distenfel S, Axen K. Effects of perceive musical rhythm on respiratory pattern. J Appl Physiol1986; 61: [15] Mockel M, Rocker L, Stork T, et al. Immeiate physiological responses of healthy volunteers to ifferent types of music: cariovascular, hormonal an mental changes. Eur JAppl Physiol Occup Physiol1994;68: [16] Bernari L, Porta C, Sleight P. Cariovascular, cerebrovascular, an respiratory changes inuce by ifferent types of music in musicians an nonmusicians: the importance of silence. Heart2006;92: [17] Besson M, Faita F, Peretz I, Bonnel AM, Requin J. Singing in the brain: inepenence of lyrics an tunes. Psychol Sci. 1998;9: [18] Platel H. Neuropsychology of musical perception: new perspectives. Eitorial Oxfor [19] Rauscher FH, Shaw GL, Ky KN. Listening to Mozart enhances spatialtemporal reasoning: towars a neurophysiological basis. Neurosci Lett. 1995;185:44 47 [20] Carstens CB, Huskins E, Hounshell GW. Listening to Mozart may not enhance performance on the revise Minnesota Paper form Boar Test. Psychol Rep. 1995;77: [21] Hughes JR, Daaboul Y, Fino JJ, Shaw GL. The "Mozart effect" on epileptiform activity. Clin Electroencephalogr. 1998; 29: [22] Steele KM, Brown JD, Stoeker JA. Failure to confirm the Rauscher an Shaw escription of recovery of the Mozart effect. Percept Mot Skills. 1999;88: [23] Hye IH, Scalapino W. The influence of music upon electrocariograms an bloo pressure. Am J Physiol1918; 46:35 8. [24] Diserens CM. Reaction to musical stimuli. Psych Bull1920;20: [25] Haas F, Distenfel S, Axen K. Effects of perceive musical rhythm on respiratory pattern. J Appl Physiol1986;61: [26] Mockel M, Rocker L, Stork T, et al. Immeiate physiological responses of healthy volunteers to ifferent types of music: cariovascular, hormonal an mental changes. Eur J Appl Physiol Occup Physiol1994;68: [27] Bernari L, Porta C, Sleight P. Cariovascular, cerebrovascular, an respiratory changes inuce by ifferent types of music in musicians an nonmusicians: the importance of silence. Heart2006;92: [28] A. Okamoto1, M. Hasegawa, T. Tamura, T. Homma an A. Komatsuzaki, Effects of Frequency an Intensity of Soun on Cochlear Bloo Flow, Acta Oto-laryngologica, 1992, Vol. 112, No. 1, Pages [29] Glass L. Synchronization an rhythmic processes in physiology. Nature2001;410: [30] Mollar AR. Noise as a health hazar. In: Maxy-Rossenau Public Health an preventive meicine. 11 th e. New York, Appleton Century Crofts 1980;790-9.

12 294 Meena Laa [31] Herbol M, Hense HW, Keil U. Effects of roa traffic noise on prevalence of hypertension in men. Soz Praventivme 1989; 34(1): [32] Harrison DW, Kelly PL. Age ifference in cariovascular an cognitive performance uner noise conitions. Percept Mot Skills 1989; 69(2): [33] Lesnik H, Makowiec DT. Hemoynamic reactions to monotonous work performe in silence an in noise of 70 B (A). Pol J Occupt Me 1989:2(1): [34] Germano G, Damiani S, Milito U, Giarrizzo C, Santucci A. Noise stimulus in normal subjects: time-epenent bloo pressure pattern assessment. Clin Cariol 1991; 14(4); [35] Green MS, Schwartz K, Harari G, Najenson T. Inustrial noise exposure an ambulatory bloo pressure an heart rate. J Occupt Me 1991; 33(8): [36] Regecova V. Effects of urban noise pollution on bloo pressure an heart rate in preschool chilren. J Hypertension 1995;13(4): [37] Kristal-Boneh E. Acute an chronic effects of noise exposure on bloo pressure an heart rate among inustrial employees. Arch Environ Health 1995;50(4): [38] Babisch W, Ising H, Gallacher JE, Sharp DS, Baker IA. Traffic noise an cariovascular risk, first phase. Arch Environ Health 1993; 48(6): [39] Babisch W, Ising H, Elwoo PC, Sharp DS, Bainton D Traffic noise an cariovascular risk, secon phase; risk estimation, prevalence, an incience of Ischaemic Heart isease. Arch Environ Health 1993;48(6): [40] Hirai A, Takata M, Mikawor M, Yasumoto K, Iia H, Sasayama S, Kagamimori S. Prolonge Exposure to inustrial noise causes hearing loss but not high bloo pressure; a stuy of 2124 factory laborer in Japan. J Hypertension 1991;9(11): [41] Evans GW, Lercher P, Meis M, Ising H, Kofler WW. Community noise exposure an stress in chilren. J Acoust Am 2001; 109(3): [42] Sawa Y. Reproucible increase in bloo pressure uring intermittent noise exposure. Eur J Appl Physio 1993; 67(4):