Introduction
Medical curriculum is a vast and complex study course with training of four and half year with one year of internship. This long period of course includes heavy load of text books and study materials, different ward or clinical postings and numerous semester and university examinations. To achieve good grades student study hard, tirelessly for longer periods of day or night and often work beyond their mental threshold and physical strength resulting in stress. Stress refers to conditions that arouse anxiety or fear. The transient rise in systolic blood pressure during stress is a common observation. 1,2,3,4,5
Several studies have shown correlation between chronic life stress and cardiovascular disease.6 Psychological stress is a risk factor for hypertension7 and coronary artery disease (CAD).6 Different physiological studies have proved that stress is linked with excessive sympathetic nervous system activation6 and thus influence the endocrine, haemopoietic and immune systems. 8 Cytokines and cortisol seem to play an important role in the communication between these systems.9 The well documented changes that occur are increase in erythrocytes, neutrophils and platelets, whereas lymphocytes, eosinophils and monocytes decrease in number. Lymphocytes and monocytes express receptors for several stress hormones, including norepinephrine and epinephrine,10 thus stressful events could alter immune function.
It has also been observed that female students respond to examination situation with stronger anxiety and more intense stress related behavioural, metabolic and psychological changes. Menstrual cycles of females also seem to get affected during the pre-examination period owing to hormonal changes as observed in previous studies.11
Cardiac parameters like pulse rate (PR), systolic blood pressure (SBP), diastolic blood pressure (DBP), Cognitive function tests like auditory reaction time (ART) and visual reaction time (VRT), Stress score (by stress questionnaire), anxiety scale and cortisol level were evaluated and compared before or at the time of examination among medical students in various studies. 12,13,14,15
Some studies have compared the difference of reaction time in male and females and thus evaluated stress (e.g., environmental). 16,17
Different factors may influence severity of stress on academic performance like age, gender, ethnicity and marital status. 18
Anxiety may be potentiated by increase in glucocorticoid which directly effects on corticotrophin releasing hormone in limbic system. 19,20
Distraction model (attentional control theory) is one of the models, developed to show effect of stress on cognitive function. In this model performance of movement execution (e.g., about the location of a target) become less accurate and more attempts or more time may be required to successfully perform a certain task and this occurs when person is under anxiety. 21,22 However, “execution focus model” argues that limited attentional resources cannot explain the negative effects of anxiety upon performance. 23
The alteration of reaction time occurs due to both physiological and pharmacological factors like stress, gender, and arousal. This alteration indicates the impairment of sensory-motor association.24
In this study Cardiovascular parameters like pulse rate (PR), systolic blood pressure (SBP), diastolic blood pressure (DBP), Cognitive function tests like auditory reaction time (ART) and visual reaction time (VRT) and Stress Score through questionnaire was evaluated and compared in presence and during absence of examination among first and second year MBBS students.
Materials and Methods
Study site/place
This study was conducted in the Department of Physiology and Pharmacology of Katihar Medical College, Katihar.
Inclusion criteria
1) First and second year MBBS students
2) ≥ 17 years of age and all the gender
3) Healthy students
Exclusion criteria
Students have history of neurological or psychiatric disorders, taking of medicines affecting emotional status and endocrinological disorder, any visual and auditory disorder, addiction to tobacco or alcohol
160 students were selected from first and second year MBBS batch before internal assessment theory examination considering after inclusion and exclusion criteria. 80 students were from first year and 70 students were from second year MBBS batch. Following tests were done.
Cardiovascular parameters
Tests like PR (Pulse Rate - beats/min) and BP (Blood Pressure- mm of Hg) were recorded in supine position by palpating radial artery and sphygmomanometer respectively.
Cognitive parameters
Test like ART (Auditory Reaction Time, in milliseconds) and VRT (Visual Reaction Time, in milliseconds) were recorded by using Audio Visual Reaction Time Machine, in a well illuminated and quiet surrounding in Physiology research laboratory. This instrument had two modes one for Auditory and another for Visual reaction time. It had three frequencies i.e. 250Hz, 500Hz and 750Hz which were randomly used for auditory stimulus. Red, Yellow and Green flashing lights were used randomly for visual stimulus. Students were directed to press the response switch by the index finger of the dominant hand as soon as the response would be perceived. The reaction time was displayed on the Reaction Time Machine and was recorded.
Stress status
Stress status was assessed by a questionnaire. Which contained 20 questions with 0-4 points given to each (i.e. no stress (Score=0) to extremely stressful (Score=4). Questionnaire was given to the students and collected after 10min to assess stress score. The total score obtained from this questionnaire was analysed. 14,25,26 According to scores given by student, stress status was interpreted like
a. Score between 0-20: - Good control over stress,
b. Score between 21- 40: - Low level of stress,
c. Score between 41- 60: - Medium level of stress,
d. Score between 60-80: - High level of stress.
On following areas of stress producing scenario, questions were framed like
Academic demands,
Peer pressure,
Lack of time for personal needs,
Interpersonal relationships including those with teaching and administrative staff.
Inability to sleep well,
Worrying,
Feeling tense and
Unhappy.
Anthropometric measurements like weight in kilograms and height in centimetres were assessed using standardised weighing machine and height measurement scale.
Studies were done for twice in following manner in all enrolled students.
Pre-examination study
All enrolled students were instructed to appear in Physiology Research Laboratory 1.15 hours prior starting the final internal examination without consuming any kind of caffeinated drinks like coffee or tea. Before starting the experimental session, students were given rest of 15 minutes. Experimental sessions were completed 10 mins before starting the theory examination.
Post-examination study
10 to 15 days after completion of final internal assessment theory examination i.e. when students were practically free of examinations, once again all students were instructed to appear in Physiology Research Laboratory on different day. They were strictly instructed to appear without consuming any kind of caffeinated drinks like coffee or tea. Before starting the experimental session, students were given rest of 15 minutes.
In 1st year students, pre-examination study was performed on 3 0 students each on 1st, 2nd and 3rd day (According to the three-subject examination in first year). In 2nd year students, pre-examination study was performed on 14 students each on 1st, 2nd, 3rd, 4th and 5th day (According to the five-subject examination in second year)
Results
Table 1
Comparison of cardiovascular parameters, cognitive parameters and stress score in pre-examination and post-examination study
All parameters like PR, SBP, DBP, VRT and Stress score were increased (extremely significant) in pre-examination as compared to post- examination study.
Table 2
Comparison of cardiovascular parameters, cognitive parameters and stress score in pre-examination study on the basis of gender
Mean PR in female students was significantly more than male students. Mean SBP and DBP in females were significantly less than males but the mean difference SBP was significant and DBP was not significant. Mean ART and VRT, both were significantly high (reaction time high) in females as compared to males. Mean stress score was also significantly less in females compared to males.
Table 3
Comparisons of cardiovascular parameters, cognitive parameters and stress scores in post- examination study on the basis of gender
During post-examination study, mean difference of PR, SBP, DBP and stress score was not significant in males and females. Compared to males, mean ART (difference not significant) and VRT (very significant) were more in females.
Table 4
Changes of cardiovascular parameters, cognitive parameters and stress scores based on gender
Delta PR (calculated by subtracting pre and post-examination study value) was increased in females as compared to males irrespective of the study setting and the difference was extremely significant. Mean difference of delta SBP, DBP, ART, VRT and Stress score were not significant between males and females.
Discussion
In pre-examination compared to post-examination study period irrespective of gender all parameters like PR, SBP, DBP ART, VRT and stress scores were increased significantly. Most common cause may be due to increase in sympathetic stimulation that increases PR and BP (both systolic and diastolic blood pressure). ART and VRT may be increased due to release of epinephrine and glucocorticoid. 26,27 Under stressful conditions, the cognitive system becomes overloaded thus reduces a person’s attentional resources. 28
Due to increased sympathetic nervous system and brain-pituitary-adrenocortical axis during stress acting either directly or indirectly can alter decision making and attention. In this study pre-examination compared to post-examination, stress score was increased significantly. This has similar result from previous study in which stress was common among first year medical students due to academic demands.2,3,29
In this study PR, ART and VRT we re increased in females as compared to males in pre-examination, but difference in PR was more significant. These findings were similar with other study.12,30
Similar to a previous study, Stress score through stress questionnaire was also significantly more in females compared to males. 31 But in pre-examination of this study, stress scores were significantly increased in males also. Difference of stress levels between males and females were not significant reported by a study. 32 PR, SBP, DBP and stress scores in males and females in post-examination study was not significantly different.
Cognitive function was decreased (i.e. both audio and visual reaction time were increased) in females as compared to males in both pre and post-examination. Increase in VRT in females may be explained by change in steroid hormone during menstrual cycle. Cognitive function of female brain is under control of ovarian steroid and this ovarian steroid has widespread effects throughout the brain regions. 33,34
Difference of studied parameters were not significantly different between both the genders except delta PR, which was significantly higher in females. Hypothalamic-pituitary-axis and autonomic nervous system activity may be increased in females due to examination stress. This could be the reason behind the increase in PR. In this study females were more distressed compared to male and this result was supported by other studies too.35
Limitations of this study was that we measured stress by questionnaire and not studied psychological factors that may influence the stress response, stress scores were obtained at only one point of time, other sources of stress such as familial or interpersonal pfroblems were not examined and internal assessment scores of the students were not correlated in this study with pre-examination stress level.
Conclusion
Cardiovascular parameters, cognitive parameters and stress scores were increased in almost all of the students irrespective of gender in pre-examination study. This may negatively affect the performance of students and can produce anxiety and/or depression subsequently. Students who are at risk of excessive stress should be identified and faculties should help them to deal the examination stress, anxiety or depression effectively and the earliest.
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