Moving from Models to Mechanisms in Yoga Research.

Introduction

In areas of holistic health, models abound; however, mechanisms are few and far between. This anomaly is seen in yoga research also, wherein Panchkosa model is presented in trying to understand the outcome of yogic “intervention.” The kosas briefly consist of annamaya or sheath composed of food, followed by four other sheaths of prana or energy, mind, knowledge, and bliss-filled ones. These form the human system starting from the gross material to the most subtle. Although this is an attractive model, we know very little about the finer sheaths of prana, knowledge, and bliss. Prana is further subdivided into five pranas, each having a specific function in the human body. We cannot say at this time how these interact with the body producing health; in general terms, it is postulated that improper flow of prana could relate to illness. Movement of prana in the subtle nadis or channels provides energy to the body for its normal functioning. However, there are no known (or reliable) instruments that could track prana either peripherally or in any specific part of the body.

Acupuncture system deals with flow of signals in meridians which are not necessarily related to nerves or to blood vessels. A system of meridians is found in some parts of the body in the recent past and is known as the Bong-Han system through which acusignals seem to traverse.[1] It is possible that prana has some relationship with electrons in the cells. Although details are available in literature regarding nadis and their possible connections to many organs and tissues of the body, there is no systematic presentation of these channels which remain esoteric to this day.

Model to Mechanism

For a model to move into mechanism, it is necessary to look into electrophysiological and biochemical pathways. Studies in electroencephalography (EEG) have revealed that for example, in meditation, different states can be distinguished.[2] Based on the EEG study, we may classify sleep, alertness, and meditation into specific taxonomy which is useful in an overall understanding of brain activity in these specific states. However, the inverse problem may not be unique. In other words, if we observe a specific EEG activity, it may not be possible to conclude that the person is in a specific mental state. Thus, even here, the question of correlation or causation cannot be resolved.

During asana practice, we observe the activity of major muscles and could use this information for effective rehabilitation.[3] Here, EMG studies reveal the activity of a group of muscles, and this information could be used in rehabilitation. Although this may not be strictly classified under mechanism, a cause-effect relation is of great help in rehabilitation.

An effective method of working toward a mechanism is through biochemical analysis. There seems to be a direct connection between emotions and molecules expressed in the body.[4] Practices in yoga include asanas, pranayama and dhyana; it is likely such practices also produce specific molecules in the body. An interesting study was reported, wherein specific molecular expression in the central nervous system (CNS) was observed using magnetic resonance imaging during chanting.[5] In this interesting study, the authors state that “The neurohemodynamic correlates of 'OM' chanting indicate limbic deactivation. As similar observations have been recorded with vagus nerve stimulation treatment used in depression and epilepsy, the study findings argue for a potential role of this 'OM' chanting in clinical practice” 5, p. 3]. Since there seems to be a specific biochemical response in the brain to OM chanting, we can use this information for clinical trials in certain CNS disorders.

Unfortunately, there are only a few studies that provide an in-depth understanding of biochemical and neurotransmitter responses to yoga. However, there are robust clinical trials available with well-controlled studies with clinical applications.[67] A patient is normally not concerned with mechanism or with causative factors. A caregiver is concerned with moving a person from ill-health to health, wherein pain, movement restriction, and improper biochemical and electrical responses are minimized so that the person could revert back to normal work and rest cycles. However, for proper scientific understanding and appropriate clinical application, a robust mechanism is required in holistic therapy.

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Conflicts of interest

There are no conflicts of interest.