استرس و شخصیت به عنوان عوامل در واکنش پذیری قلبی عروقی زنان

Abstract An experiment was conducted to investigate the relationships among Type A behavior, hostility and cardiovascular reactivity (CVR) in women. Changes in heart rate, blood pressure and skin conductance from baseline to task levels were used to assess reactivity. These measures were obtained from 96 women during a seated baseline period, a reaction time task and during an oral IQ quiz. Analyses indicated that Type A and high hostile women were more reactive to an oral IQ quiz and reaction time stressors than Type B and low hostile women. Specifically, Type As showed significantly greater increases in systolic blood pressure in the reaction time task and greater mean arterial pressure and systolic blood pressure increases in the IQ quiz. High hostiles evidenced significantly higher systolic blood pressure and diastolic blood pressure in the RT task and higher mean arterial pressure and diastolic blood pressure in the IQ quiz. It was concluded that Type A personality and hostility can predict greater reactivity in women to two different stressors. The oral quiz generated greater reactivity than the RT task and thus may be a more stressful task.

. Results Raw scores, percentiles and other descriptives were computed for Type A and hostility. Raw scores, T scores and various descriptives were computed. Hostility T scores have a mean of 50 and a S.D. of 10. Reactivity scores were computed as the difference between physiological readings from baseline to task for each of the five physiological dependent variables. This was done for both the reaction time task and the oral IQ quiz. Thus, for each condition there are five reactivity scores (change scores) or dependent variables. Table 1 shows mean baselines and reactivity readings (task level — baseline) for the RT and IQ quiz conditions for Type A and B women. With the exception of SBP, the baselines of Type As and Bs were not significantly different. The only significant difference was for SBP (Type A=104.5 mm Hg, Type B=110.7 mm Hg), t(64)=2.32, P<0.05. Table 1. Mean cardiovascular measures during baseline, and reactivity (baseline — task level) during reaction time and oral IQ quiz tasks for Type A (n=32) and Type B (n=32) women Physiological measure Baseline and reactivity measures Baseline Reaction time IQ quiz A B A B A B Mean arterial pressure 77.7 80.2 6.25 4.10 9.60 5.88 Heart rate 80.2 78.2 5.06 3.15 5.68 5.09 Systolic blood pressure 104.5 110.0 7.01 3.01 10.59 4.41 Diastolic blood pressure 61.8 62.4 3.91 2.23 5.91 4.17 Skin conductance 9.0 9.2 4.54 3.01 6.07 4.83 Note: Heart rate is expressed in beats per minute (b.p.m.), blood pressure measured in mm Hg, and skin conductance measured in microohms. Table options Spearman rank correlations were computed to determine the degree to which Type A was related to physiological reactivity for both tasks. For reaction time, most of the correlations were positive; however, few were significant. Type A was significantly correlated with change scores for SBP, rs=0.241, P<0.05; and DBP, rs=0.209, P<0.05. Most correlations between reactivity measures and Type A were positive for the oral IQ quiz condition. Type A was correlated with MAP, rs=0.341, P<0.01; SBP, rs=0.332, P<0.01; and DBP, rs=0.218, P<0.05. Given several significant correlations between reactivity, Type A and hostility, a series of 2×2 (Type A/B by task) repeated measures analyses of covariance (ANCOVA) were computed to assess differences in reactivity between Type A and Bs. Each ANCOVA included the baseline of the physiological variable being analyzed, as a covariate. These ANCOVAs were used for the between-subjects main effect of Type A/B, the within-subjects main effect for the task (RT vs. IQ quiz) and the interaction between type and task. Fig. 1 and Fig. 2 show mean reactivity for each task; Type A women were more reactive than Type B in MAP, F1,61=5.54, P<0.01; SBP, F1,61=10.93, P<0.01; and skin conductance, F1,61=6.04, P<0.05. For DBP, results were marginally insignificant, F1,61=3.76, P=0.057. There were no significant interactions between Type A personality and the task. Reactivity of Type A and B during reaction time task. Error bars represent ... Fig. 1. Reactivity of Type A and B during reaction time task. Error bars represent standard errors of the mean. Figure options Reactivity of Type A and B during an oral IQ quiz. Error bars represent standard ... Fig. 2. Reactivity of Type A and B during an oral IQ quiz. Error bars represent standard errors of the mean. Figure options A median split was used to bifurcate participants into high (n=48) and low (n=48) hostility groups. Table 2 shows mean baselines and reactivity readings (task level — baseline) for the RT and IQ quiz conditions for high and low hostile women. Spearman rank correlational analyses indicated some relationship between reactivity and raw hostility scores. In particular, hostility scores were correlated with SBP reactivity during reaction time, rs=0.20, P<0.05. For the oral IQ quiz, hostility was related to changes in MAP, rs=0.238, P<0.05; SBP, rs=0.224, P<0.05; and DBP, rs=0.286, P<0.05. Table 2. Mean cardiovascular measures during baseline, and reactivity (baseline — task level) during reaction time and oral IQ quiz tasks for high hostile (n=48) and low hostile (n=48) women Physiological measure Baseline and reactivity measures Baseline Reaction time IQ quiz High Low High Low High Low Mean arterial pressure 78.4 79.4 6.32 4.16 9.45 6.24 Heart rate 79.9 78.6 5.27 3.08 5.57 5.21 Systolic blood pressure 107.1 108.0 7.37 2.92 9.34 5.88 Diastolic blood pressure 62.7 61.6 4.21 2.06 6.49 3.76 Skin conductance 8.8 9.3 3.96 3.61 5.53 5.38 Note: Heart rate is expressed in beats per minute (b.p.m.), blood pressure measured in mm Hg, and skin conductance measured in microohms. Table options A series of 2×2 (hostile/non-hostile by task) repeated measures ANCOVAs were used to assess differences in reactivity. Baseline physiological measures were used as the covariate. Fig. 3 and Fig. 4 show mean reactivity scores for RT and IQ quiz tasks. Results indicated that the main effect for hostility was significant. In particular, high hostile women were more reactive in terms of MAP, F1,61=4.83, P<0.05; SBP, F1,61=7.18, P<0.01; and DBP, F1,61=7.91, P<0.01. There were no significant interactions between task and hostility. Reactivity of high and low hostility scorers during reaction time. High scorers ... Fig. 3. Reactivity of high and low hostility scorers during reaction time. High scorers include those scoring at the 50th percentile or higher on the Cook–Medley Ho scale. Low scorers scored below the 50th percentile. Error bars represent standard errors of the mean. Figure options Reactivity of high and low hostility scorers during the oral IQ quiz. High ... Fig. 4. Reactivity of high and low hostility scorers during the oral IQ quiz. High scorers include those scoring at the 50th percentile or higher on the Cook–Medley Ho scale. Low scorers scored below the 50th percentile. Error bars represent standard errors of the mean. Figure options Examination of Fig. 1, Fig. 2, Fig. 3 and Fig. 4 show that for all five physiological measures, participants were more reactive to the IQ quiz than reaction time. The analysis revealed several significant main effects for task indicating this greater reactivity in: MAP, F1,61=13.39, P<0.01; SBP, F1,61=7.63, P<0.01; DBP, F1,61=11.67, P=0.001; and skin conductance, F1,61=27.00, P<0.001. To analyze the possible effects of various combinations of Type A and hostility, four categories were formed and differences among them were assessed. Category 1 included Type A and high hostile participants; category 2, Type A and low hostile; category 3, Type B high hostile; and category 4, Type B and low hostile (see Table 3). Categories 1 and 4 were conceptually the most different (Type A high hostile and Type B low hostile). Table 3. Mean cardiovascular reactivity for combinations of Type A and hostility (categories 1–4) Physiological Reactivity measures (task — baseline) measure 1 (n=23) 2 (n=8) 3 (n=7) 4 (n=26) Type A Type A Type B Type B High Ho Low Ho High Ho Low Ho Reaction time MAP 6.44 6.60 5.92 3.41 Heart rate 5.45 5.18 4.69 2.42 Systolic BP 7.49 6.57 7.0 1.80 Diastolic BP 4.63 2.68 2.80 1.87 Skin conductance 4.14 5.78 3.40 2.94 IQ quiz MAP 10.1 8.47 7.28 5.55 Heart rate 5.54 6.68 5.66 4.76 Systolic BP 10.86 10.22 4.33 4.55 Diastolic BP 6.36 4.77 6.92 3.45 Skin conductance 5.74 7.31 4.85 4.69 Note: MAP, mean arterial pressure; BP, blood pressure; Ho, hostility. Heart rate is expressed in beats per minute (b.p.m.), blood pressure measures in mm Hg, and skin conductance measured in microohms. Table options An ANOVA comparing the four Categories demonstrated that there were several significant differences between the groups. Subsequent post-hoc analyses (Scheffe') indicated that, in particular, members of category 1 (Type A high hostile) were more reactive to the reaction time task in terms of SBP than category 4 (Type B low hostile), F3,60F=3.75, P<0.05. For the IQ quiz, category 1 demonstrated greater reactivity than category 4 in terms of MAP, F3,60=2.90, P<0.05 and SBP, F3,60=4.36, P<0.01.