Cardiovascular and sympathoadrenal responses to mental stress: influence of beta-blockade

Abstract

Cardiovascular, sympathoadrenal, and subjective responses to mental stress induced by a color-word conflict test (CWT) were studied in 30 healthy males before and after intravenous administration of either placebo, beta 1-blockade by metoprolol (0.15 mg/kg), or nonselective beta-blockade by propranolol (0.15 mg/kg). CWT responses were reproducible. Mean arterial pressure increased by 20%. A mainly heart rate-dependent 65% increase in cardiac output (thermodilution) was associated with 25% decreases of both systemic (SVR) and calf vascular (CVR) resistances. Arterial plasma epinephrine (Epi) was doubled, and norepinephrine (NE) increased by 50%. Self-evaluated stress score correlated positively with changes in cardiac output and inversely with changes in SVR during CWT. Both metoprolol and propranolol halved heart rate responses; whereas increases in mean arterial pressure, Epi, and NE were uninfluenced. Metoprolol reduced the increase in stroke volume, and propranolol abolished it. SVR and CVR responses were attenuated by metoprolol and abolished by propranolol. The results suggest that mental stress accelerates the heart through neurogenic mechanisms and that peripheral vasodilatation is achieved through the concerted actions of reduced vasoconstrictor activity and elevated circulating Epi.

Professional examination stress induced hemodynamic changes in first year MBBS students

“…Increase in PR, SBP one hour prior to exam occurs possibly as a result of sympathetic activation. This is consistent with the findings of Freychuss et al & Malathi et al who contributed it to increased epinephrine levels 1,3 .…”

“…Other researchers also reported a similar trend of increasing pulse rate, blood pressure, and galvanic skin resistance during examination stress. 1,12 Our study also observed that 29(60.4 %) male and 47 (78.3%) female students were having increase in pulse rate and systolic blood pressure one hour before the examination compared to pulse rate(PR) and systolic blood pressure(SBP) ten days before and ten days after the examination. Bazmi Inam 13 has noted prevalence of increase anxiety in females to be 89.7% and males 60% in 1st year medical students of Saudi Arabia.…”

“…Human body respond to stress by alterations in different biological functions particularly autonomic function like increase in heart rate and blood pressure 1 . There are many possible stressors to which medical students may be exposed like pressure of a meticulous academic curriculum coupled with recurrent examination and other sources of stress include personal factors such as staying away from family, tuning to unfavorable hostel conditions, parental expectations.…”

Sympathetic activity is influenced by task difficulty and stress perception during mental challenge in humans.

“…To generalize, mental tasks elicit primarily cardiac output (mostly heart rate)-mediated elevations in arterial pressure (Hejl, 1957) as observed in most subjects in this study. Studies of responses to mental tasks during f8-blockade (Nyberg, Graham & Stokes, 1977;Freyschuss, Hjemdahl, Juhlin-Dannfelt & Linde, 1988) suggest that if one mechanism (e.g. heart rate) for elevating arterial pressure during the task is constrained or eliminated, a different mechanism will compensate so that a given increase in arterial pressure is generated.…”

Sympathetic function tests during pre and #8209; and post and #8209;menstrual phases in young women

“…Rise in BP due to stress leads to increased epinephrine secretion and this rise in BP is important sympathoadrenal response to physiological stressful experience caused by pre-menstrual stress. [16] Most evidence suggest that there is decrease in serotonin and beta-endorphins level during pre-menstrual phase and this might be associated with changes in mood and behavioral symptoms. [1,17,18] Thus during different phases of menstrual cycle neurohormonal changes, stress, and sympathetic activity are interrelated to each other.…”