In the recent years, the individualized approach to therapeutics has received impetus with the growing understandings in the field of genetics. Several workers have investigated the possible association of constitutional types with the individual genetic make-up, metabolic abilities and chronic diseases. There have been several efforts to see whether certain physiological, haematological or biochemical tools can be used to establish a link between constitution types and other health-related parameters. (Aggarwal et al., 2010; Bhalerao and Deshpande, 2012; Dey and Pahwa, 2014; Ghodke et al., 2011; Patwardhan et al., 2005; Prasher et al., 2008).
A few workers in the past have hypothesised that certain autonomic responses might vary in accordance with the constitutional types as defined in Ayurveda (Thompson, 2005). One of the early studies in this regard has reported that the healthy individuals with
With this background, we planned the present study to investigate a possible relationship between certain autonomic responses and
The approval from the institutional ethics committee was obtained before starting the study.
The population for the present study was defined in terms of students who were aged between 17 - 35 years and registered under various courses of study at our institution.
Sampling and inclusion criteria
The students were informed about the study in their classrooms through verbal announcements. The details of the study were explained to them and their voluntary participation in the work was solicited. After obtaining the written consent from those who responded to our request, a thorough clinical examination was carried out to confirm that they were clinically healthy. A detailed pro-forma was used to record the findings of the interview that included history taking and physical examination. Those who gave no history of any acute /chronic illnesses, or did not complain of any physical / psychological symptoms, and those who were found to be ‘within the normal limits’ on all parameters of systemic physical examination, were defined as ‘clinically healthy’ and were included in the study. Blood biochemistry or hematology parameters were not assessed. Students with obesity were excluded (one volunteer).
There are quite a few difficulties that have been reportedly encountered in determining one’s Ayurveda constitution (
To avoid these problems, the latest version of the ‘Self assessment questionnaire for determining
This tool uses simple questions or statements that reflect each trait / feature as described in
We determined the
Performing the autonomic function tests
All the registered volunteers (n = 106) underwent the following tests to record cardiovascular and pupillary responses. The tests related to pupillary reactions were carried out in the noon hours (11 am to 1 pm) whereas those related to cardiovascular responses were carried out in the evening hours (4 pm to 7 pm). However, due to some practical difficulties, we could not record the pupil cycle time in 5 enrolled volunteers, rendering the total sample size in this case to 101.
The test is conducted in following steps:
1) The test is explained to the subject and he/she is made to sit on a chair comfortably. The baseline blood pressure is recorded. 2) The subject is asked to immerse one hand up to the level of wrist in cold water maintained at 4 to 5°C for 2 min. The Blood Pressure (BP) is recorded from the other arm at 30 sec intervals. 3) The maximum increases in systolic and diastolic pressures are noted and compared with the baseline readings.
The Systolic Blood Pressure (SBP) normally increases by 16 - 20 mmHg, while the Diastolic Blood Pressure (DBP) normally increases by 12 - 15 mmHg on an average. Reduced Sympathetic activity is indicated by a lesser than 16 mm Hg rise in SBP and lesser than 12 mm Hg rise in DBP (Ghai, 2007; Noronha et al., 1981).
Standing-to-lying ratio (S/L ratio)
When a normal person lies down from a standing position, there is at first a rise in Heart Rate (HR) which then is slowed down. This rise and fall of HR is due to changes in the vagal tone. The test is performed in following steps:
1) The procedure is explained to the subject. ECG leads are connected for recording lead II. The subject is asked to stand in the upright position quietly for two minutes and without taking any support is then asked to lie down supine. 2) ECG is recorded for 20 beats before and for 60 beats after lying down. The point of change of position on the ECG paper is noted. 3) Calculation of S/L ratio: The average of R-R interval during 5 beats before lying down is noted and the shortest R-R interval during 10 beats after lying down is also noted down. Any abnormally low ratio indicates parasympathetic insufficiency, the normal ratio being > 1 (Ghai, 2007).
Valsalva manoeuvre is defined as the forced expiration against a closed glottis. This straining, associated with changes in HR, is a simple test for baroreceptor activity.
1) The subject is seated on a stool and procedure is explained to him / her. ECG leads and BP cuff are connected to him / her, and the nostrils are closed with a nose clip. 2) The cuff is disconnected from another BP apparatus and the subject is asked to take a deep breath, blow into the manometer and maintain the pressure at 40 mm Hg for 15 s. 3) ECG (lead II) is recorded for 1 minute before the straining, and for 45 s after the release of strain. 4) Calculation of Valsalva Raio: The Valsalva ratio is calculated as the ratio of the longest RR interval after manoeuvre to shortest R-R interval during manoeuvre. A value > 1.21 is taken as normal and a value less than that is indicative of parasympathetic insufficiency (Neumann and Schmid, 1997).
During the straining there is decrease in venous return, fall in cardiac output, and vasoconstriction. The HR increases throughout straining due to vagal inhibition initially and sympathetic activation later. After this, the HR slowly decreases. A failure of HR to increase during straining suggests sympathetic insufficiency, while failure of HR to slow down after the effort suggests a parasympathetic insufficiency (Ghai, 2007).
Besides the cardiovascular autonomic activity evaluation tests, the pupil has been recognized to be a useful parameter for the study of the physiology of autonomic nervous system. It has exclusively autonomic innervations, and is accessible in vivo to direct influences of physical and chemical agents (Cahill et al., 2001)
Stimulation of the parasympathetic division leads to the contraction of the constrictor muscles of the pupil resulting in miosis. On the other hand, stimulation of sympathetic nerves causes contraction of dilator pupillae resulting in mydriasis (Patel , 1999). Various methods have been used to measure pupillary functions, however, the pupil cycle time and the pupil diameter measurement in light and dark are the useful ones.
We captured the photographs of right and left eyes of the subjects from a uniform distance of 1.5 feet with the Nikon coolpix 6500 camera mounted on a tripod. We also managed to set each subject’s image with uniform 4× optical zoom. For the measurement of light-adapted pupil size, we captured the eye image in the 40 watt tube-light illumination from a fixed direction. For the measurement of dark-adapted pupil size, we captured the image in darkroom by switching the lights off. We waited for 30 sec after switching off the lights and thereafter, we captured the image of the eye using an inbuilt flash light with camera set at shutter speed of 1/125. After capturing the image we transferred this image on to the computer and measured the photographic corneal size and photographic pupil size with the Vernier scale. We then calculated the pupil size using the following algebraic formula:
Where, actual corneal size was directly measured by placing the Vernier scale in front of the subject’s eye.
The pupil cycle time was measured in both the eyes using a slit lamp and a connected computer with video recording facility. This is a modification of the method described by Miller and Thompson (Miller and Thomson, 1978). Intensity of illumination was kep t fixed for the entire study. The volunteer was comfortably seated at the slit lamp in a dimly lit room. He/she removed his/her spectacles if he/she wore one. A 0.5 mm thick slit beam of light was focussed on to the pupillary margin. The beam was then adjusted in a manner so that half of the slit fell on iris and half entered into the pupil. Pupil contracted due to retinal stimulation and prevented further entry of light in the eye. With the retina now in darkness, the pupil dilates to allow the entry of light into the eye, thus setting up persistent oscillations. 30 s of time was fixed for capturing the pupillary oscillation video in the computer. We then counted the number of oscillations of pupil per 30 s and calculated the average time taken for each cycle. The average time taken was then expressed in terms of milliseconds.
For comparing the various mean readings of different tests among different
After administering the self-assessment tool to determine
[Table 1.] Percentage-wise distribution of Doshik contribution in volunteers belonging to different groups
Percentage-wise distribution of Doshik contribution in volunteers belonging to different groups
[Table 2.] Distribution of the whole sample (n = 106) according to the score-range for Vata, Pitta and Kapha
Distribution of the whole sample (n = 106) according to the score-range for Vata, Pitta and Kapha
The consolidated Table 3 shows the results of all the tests, except for pupil cycle time which are shown in Table 4. From the Table 3 it can be seen that the maximum increase in systolic and diastolic blood pressure during the cold exposure varied significantly as per primary
[Table 3.] Variables of Autonomic functions in relation to Primary Dosha of the participants
Variables of Autonomic functions in relation to Primary Dosha of the participants
[Table 4.] Variables of pupil cycle time in relation to Primary Dosha of the participants
Variables of pupil cycle time in relation to Primary Dosha of the participants
Table 4 suggests that the pupil cycle time varied significantly in right eye as per primary
The tool that we have used in the present study assumes that each
In this kind of relative calculation, if the score-wise contributions of
In the present tool that we have used in our study, however, the results are derived in terms of absolute percentage values, where, the calculation of contribution of one
Though, ‘which kind of a tool is ideal and suitable for research’ is a matter of debate, the absolute expression has certain edge over the relative expression because it gives a precise idea about the extent of expression of a particular
From a point of scientific curiosity, we also tried classifying the sample on the basis of ‘two most dominant
The autonomic nervous system has two components: a. Sympathetic, and, b. Parasympathetic. The sympathetic activity is dominant during emergency “fight-or-flight” situations and during exercise. The effect of sympathetic stimulation under such circumstances is to prepare the body for vigorous physical activity by increasing the blood flow to the skeletal muscles. The parasympathetic system, on the other hand, is dominant during quiet, resting conditions. The effect of the parasympathetic system in such situations is to conserve energy and to regulate basic body functions such as digestion, and, an optimal, moderate heart rate (McCorry, 2007).
According to the concept of constitution in Ayurveda,
As the results of Cold Pressor Test indicate, the sympathetic activity in
The overall impression that we could gather from this study is that
A relatively small sample size of the study limits the generalizability of the results to a larger population. Volunteers belonging to both the genders were included in the study; hence, it ignores any possible gender differences with respect to autonomic responses.
The study suggests that people with