Autonomic and endocrine functions and music
Music has been used for therapeutic purposes for many years. However, the precise mechanisms by which music may improve human well being (especially in terms of stress) still remain unclear. There has been no definition of stress that everyone accepts. The most common one defines stress as "physical, mental, or emotional strain or tension". But stress is not always harmful. In contrast it can also result in increased productivity. This kind of good stress is also called eustress.
Biochemical aspects of (eu)stress
In general the hypothalamic-pituitary-adrenal axis and the stimulation of the sympathetic nervous system and epinephrine secretion play an important role in the physiological and biochemical factors of negative stress. The sympathetic system becomes more active during times of stress. It mediates the neuronal and hormonal stress response commonly known as the fight-or-flight response. Furthermore it accelerates activity of the heart and is involvoled in the secretion of epinephrine and norepinephrine from the kidneys.
Interleukin-6 belongs to the family of cytokines and plays an important role in the control of the immune system. It stimulates the immune response to burns or other tissue damage leading to inflammation. In the serum of healthy subjects the sIL-6-receptor occurs in a concentration of 25-35 ng/ml. This level increases significantly with various illnesses such as HIV and leukemia. IL-6 itself increases the secretion of cortisone and epinephrine (so called adrenaline).
Effect of music on cytokines and neurotransmitters
In a study by Conrad et al., critically ill patients were studied to identify mechanisms of music-induced relaxation[1]. Five patients were exposed to Mozart's piano sonatas during the first post-surgical hour. Five patients in the control group were not exposed to any music after surgery. Conrad et al. observed that the average blood pressure was increased in the control group, but decreased in the music group. Additionally, patients of the music group did not require any further sedations by Propofol. Moreover, levels of growth hormone remained unchanged in controls, but rose after music by 60%. IL-6 and epinephrine levels remained unchanged in controls, but decreased significantly after music therapy by 83%, respectively 55%. This study demonstrates that the effect of music on pituitary growth hormone release may be central to the sedative actions of music. That implies that music influence on IL-6 availability may then be the crucial pathway of stress reduction.
Effect of music on physiological parameters
Bernardi et al. studied the effect of two minute lasting presentations of different styles of music on the cardiovascular, cerebrovascular, and respiratory systems[2]. They observed that the faster the tempi the higher ventilation, breathing rate, blood flow velocity, systolic and diastolic blood pressures and heart rate. It is worth mentioning that these effects appeared to depend on the speed of the music rather than on the style. But the most interesting finding is that "listening" to a two minute rest was characterized by the lowest rates of these factors[3]. Hence, passive listening to music accelerates breathing and increases blood pressure and heart rate proportional to the tempo and perhaps to the complexity of the rhythm.
In general, an arousal effect proportional to the speed of music was observed, where slower rhythm induced relaxation. Especially a pause may be crucially important in determining some of the relaxing effects of music. These findings imply an alternative technique of relaxation without the active participation of the subject, that in turn could be very helpful in comatose patients. An appropriate selection of music and pauses can be used to induce relaxation and reduce sympathetic activity that may be potentially useful in the management of cardiovascular diseases.
Musicogenic epilepsy
Finally, I want at least to touch on a negative effect of music, namely musicogenic epilepsy. There are patients with music induced epileptic seizures. Hereby causing music varies from patient to patient (e.g.: classical music, oldies, memory-laden songs etc.). A well-known case of this disorder is the music critic Nikonov who had to finally give up his profession and avoided any contact with music for the rest of his life[4].
References
- ↑ Conrad, C.; Niess, H.; Jauch, K.W.; Bruns, C.J.; Hartl, W.; Welker, L. (2007). "Overture for growth hormone: requiem for interleukin-6?". Crit Care Med 35 (12): 2709-13. DOI:10.1097/01.CCM.0000291648.99043.B9. Research Blogging.
- ↑ Bernardi, L.; Porta, C.; Sleight, P. (2006). "Cardiovascular, cerebrovascular, and respiratory changes induced by different types of music in musicians and non-musicians: the importance of silence". British Medical Journal 92 (4): 445. DOI:10.1136/hrt.2005.064600. Research Blogging.
- ↑ Larsen, P.D.; Galletly, D.C. (2006). "The sound of silence is music to the heart". British Medical Journal 92 (4): 433. DOI:10.1136/hrt.2005.071902. Research Blogging.
- ↑ Kaplan, Peter W. (2003). "Musicogenic epilepsy and epileptic music: a seizure's song". Epilepsy & Behavior 4 (5): 464-473.