In today’s fast life, every person is part of a race; a race in which everyone has to win by achieving their goals. But to achieve this, a person should be mentally and physically fit. And that’s only possible when there is a deep understanding of a person’s physiology. Ayurveda serves the same purpose. Ayurveda is one of the ancient and helpful sciences of life. According to it, a person is completely fit when there is a balance between Doshas, Dhatus, Agni, and Mala. It leads to a harmonic state of all bodily functions including the harmony of mind and soul. It is entirely based on the theory of Tridosha – Vata, Pitta, and Kapha Doshas.

Amongst these three entities, Vata Dosha is the controller and impeller of all mental functions and is the employer of sensory functions. It is the controlling factor of all the movements within the body. It promotes speech, the origin of sound and touch, and brings compactness to the body. It also plays an important role in both the healthy and diseased condition of an individual. It helps in the absorption of Doshas, travels through gross and subtle Srotas in the body, and gives shape to the embryo.

Vata Dosha is further divided into five types, namely- Prana, Udana, Samana, Vyana, and Apana. Amongst these, Samana Vayu is present in Jatharagni and covers the entire gastrointestinal tract. Its role is to stimulate Agni for the digestion process and also helps in the segregation of Prasada essence and katu essence after digestion. It receives ingested food by Prana Vayu and after digestion, the waste generated is removed by Apana Vayu. All these Vayus together perform various physiological functions. When Samana Vayu is in harmony, Jatharagni is considered as Samagni. When it is not in harmony i.e. when it becomes vimargaami, it causes Vishama Agni. When associated with Pitta Dosha- causes Tikshna Agni and when associated with Kapha Dosha- causes Manda Agni. When there is over-accumulation of Saman Vayu, it leads to abdominal tumors, weakness in digestion, and diarrhea.

Concept of Annam Grihnati:
Annam Grihnati means receiving and withholding the food in the gastrointestinal tract, and this function is of Samana Vayu with the coordination of Prana Vayu.

The entire mechanism in terms of modern medicine takes place in three stages:

1. The stage of swallowing:

This stage is a voluntary stage. While chewing food, pressure is applied by the tongue in an upward and backward direction against the palate, causing the squeezing of food into the pharynx.

2. The pharyngeal stage of swallowing:

This stage is an involuntary stage in which the epithelial swallowing receptor around the pharynx is stimulated. Later, the impulses are transmitted through trigeminal and glossopharyngeal nerves (sensory portions) into the medulla oblongata.

3. Esophageal stage of swallowing:
The food from the pharynx is conducted into the stomach by the esophagus. It involves propulsive and mixing movements.
The three stages of Annam Grihnati are:

1.Annam Pachati:
It is the digestion and metabolism of food by Agni. Samana Vayu stimulates Agni to undertake digestion and metabolism processes.

2. Annam Vivechayati:
It is the segregation of essence and waste products of digested food. Later, the absorption of essence is part of food, water, minerals, etc. The water part of the essence is absorbed by the process of Osmosis. Absorption of sodium is done by epithelial cells, glucose by sodium-glucose co-transporter, proteins by sodium amino acid co-transporter, and calcium by parathyroid hormone.

3. Munchati:
It is the excretion of waste via feces and urine. Excretion is supported by Apana Vayu. Apana Vayu is stimulated by Samana Vayu for the excretion of waste. In this massive movement of feces until withdrawal, two types are reflexes are observed:

A. The first is the intrinsic reflex which is mediated by ENS (Enteric Nervous System) in the rectal wall. When feces enter the rectum, distention of the rectal wall occurs, which stimulates sensory signals through the myenteric plexus and causes peristalsis from descending colon to the sigmoid and rectum. This causes relaxation of the internal sphincter and when the external anal is open, excretion takes place.

B. The second reflex is initiated by parasympathetic nerves. After the entry to fecal matter in the rectum, parasympathetic nerves transmit signals to the spinal cord. These signals help in the relaxation of the internal anal sphincter and voluntary defecation occurs.

Thus, we can conclude that the primal role of Samana Vayu is to stimulate Agni and lead to digestion, absorption, and separation of the essence and waste material. Hence, for the body to function properly, it becomes necessary to maintain Vata dosha as it is connected to an important mechanism of the body, viz. digestion, and elimination of wastes.