22 To remove any spurious LF due to slow respiration, we calculated the LF and HF power of the respiratory signal and then removed from the RR LF power the proportion of the LF due to respiration. 21 This ratio reflects the sympathovagal balance only when the respiratory oscillations remain in the HF band. We evaluated sympathovagal balance by the ratio between low (LF) (from 0.03 to 0.15 Hz) and high frequency (HF) components (0.15 to 0.40 Hz) of heart rate variability. 21 This method is particularly well suited for relatively short term sequences (two or four minute). Baroreflex sensitivity was calculated from the same sequences of RR interval and systolic blood pressure by autoregressive power spectral analysis of the RR interval and systolic blood pressures (α index). Mean values for heart period (RR interval) and systolic blood pressure were obtained, after discarding the first 30 seconds. Breathing rate, relative tidal volume, minute ventilation, and end tidal carbon dioxide were calculated for each breath. Optical disk storage allowed further analysis. Table 2 2 shows details of these music tracks.Īll signals were continuously acquired on a personal computer (Apple Macintosh G3, Cupertino, California, USA) at a frequency of 600 samples/channel. Then, in random order with no intervening pauses, presentations of two minute periods of (1) slow classical, (2) fast classical, (3) dodecaphonic, (4) techno, (5) rap, and (6) raga music began. 12 End tidal carbon dioxide was monitored by a nasal cannula and side stream capnography (COSMOplus, Novametrix, Wallingford, Connecticut, USA).īaseline recordings were taken for five minutes. In a steady state the amplitude of this signal has excellent intrasubject correlation with tidal volume recorded with a facial mask or a mouthpiece and a pneumotachograph, but avoids the respiratory modifications induced by such devices. Respiratory movements were continuously evaluated by inductive plethysmography expressed as a percentage of baseline values. 20 Mid‐cerebral artery blood flow velocity was monitored by a 2 MHz transcranial Doppler (TCD) probe at a depth of 35–55 mm through the temporal window of the non‐dominant side (DWL, Sipplingen, Germany). This method faithfully tracks changes in invasive blood pressure.
19 After subjects had a 20 minute period of quiet rest, we continuously monitored heart rate (RR interval) from the ECG (chest leads) and non‐invasive beat to beat blood pressure by applanation tonometry at the radial artery (Pilot model Colin tonometry, San Antonio, Texas, USA).
18 The subjects avoided tapping with a finger or foot (to avoid artefactual entrainment), confirmed by continuous visual monitoring. We measured cardiovascular, respiratory, and cerebrovascular variables and their short term reproducibility and habituation, as well as the non‐specific effect of a random order of presentation.Īll tests were carried out in comfortable temperature, humidity, and light, with the subjects supine and wearing headphones (keeping their eyes closed). We investigated the responses to six types of music (with differing rhythmic, harmonic, and melodic structures) in musicians versus non‐musicians. 16, 17 We therefore investigated whether listening to music has similar effects. Cardiorespiratory variables can be modified by rhythmic repetition of a prayer or a yoga mantra or by recitation of poetry. 1, 14, 15 So far, however, autonomic, cardiovascular, and respiratory changes in response to such a large range of music, order of presentation, or the effect of a short interpolated pause, and the responses related to musical training have not been comprehensively compared. 13 Heart rate, blood pressure, or respiration have been studied. 13 These responses may be influenced by musical style (for example, classical versus rock), melody, harmonic structure, rhythm, and tempo but also by verbal content-for example, the brain asymmetry shown for language and melody perception has not been found in rhythm perception. 11, 12 Non‐musicians listen by using the non‐dominant hemisphere, whereas musicians (who are probably more attentive) use the dominant hemisphere. Listening to music is a complex phenomenon, involving psychological, emotional, neurological, and cardiovascular changes, with behavioural modifications of breathing. Music can reduce stress and improve athletic performance, motor function in neurologically impaired patients with stroke or parkinsonism, or milk production in cattle. Music now has an increasing role in several disparate areas.
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