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Biomedical subjects

George D Bishop

Publications and source records attributed to George D Bishop.

8 recordsLinked to original sources
PubMed2006

Blunted cardiovascular responses to daytime activities as related to reduced nocturnal blood pressure decline.

BACKGROUND: Individuals showing less than a 10% decline in blood pressure at night ("nondippers") are known to be at increased risk for hypertension and other cardiovascular conditions. PURPOSE: This research tested the assertion by Räikkönen et al. (1) that nondippers show blunted cardiovascular responses to activities during daytime hours. METHODS: Ambulatory blood pressure and impedance monitoring was performed with 149 young adults in Singapore. At each daytime blood pressure reading, participants completed a computerized questionnaire indicating location, posture, physical activities, feelings, and social interactions. RESULTS: Significant interactions between dipper status and feeling tired, location, posture, and physical activity provided qualified support for the blunting hypothesis. However, blunting of BP responses was not attributable to blunting of either cardiac output or total peripheral resistance responses. CONCLUSION: Nondippers appear to show blunted daytime responses to certain types of daytime activities. However, these effects are limited and appear to be the result of different mechanisms than those responsible for reduced nighttime blood pressure decline.

Adolescent↗
PubMed2005

The relationship of hostility, negative affect and ethnicity to cardiovascular responses: an ambulatory study in Singapore.

This study tested the hypotheses that ambulatory heart rate and blood pressure would be higher for individuals high but not low in hostility when they experienced negative affect or social stress and that this interaction would be stronger for Indians compared with other Singapore ethnic groups. Ambulatory blood pressure monitoring was done on 108 male Singapore patrol officers as they went about their daily duties. After each BP measurement participants completed a computerized questionnaire including items on emotional experience. Individuals high in hostility showed higher systolic blood pressure when reporting negative affect whereas this was not true for those low in hostility. Ethnic differences were obtained such that Indians showed an increase in mean arterial pressure when angered whereas MAP was negatively related to anger for Malays and unrelated for Chinese. Also a three-way interaction between ethnicity, hostility, and social stress indicated that hostility and social stress interacted in their effects on DBP for Indian participants but not for Chinese or Malays. Finally, a three-way interaction was obtained between ethnicity, hostility and negative affect for heart rate in which heart rate increased with increasing levels of negative affect for Chinese high in hostility and Malays low in hostility but decreased with increasing negative affect for all other participants. These data are consistent with higher CHD rates among individuals high in hostility and also provide additional evidence on ethnic differences in cardiovascular reactivity in Singapore.

Adult↗
PubMed2005

The use of ecological momentary assessment to test appraisal theories of emotion.

Although appraisal theories have received strong empirical support, there are methodological concerns about the research, including biased recall, heuristic responding, ethical issues, and weak and unrealistic induction of emotions in laboratories. To provide a more ecologically valid test of appraisal theories, the authors used ecological momentary assessment, in which the emotions and appraisals of Singaporean police officers were measured online over the course of an ordinary workday. The research focused on happiness. Support was obtained for predictions, demonstrating the generalizability of appraisal theories to a nonlaboratory setting and circumventing the shortcomings of previously used methodologies. Also, evidence was obtained that happiness was reported primarily in association with a specific combination of 3 relevant appraisals: high pleasantness, high perceived control, and low moral violation.

Adult↗
PubMed2005

Ethnicity, sex, trait anger, and nocturnal blood pressure decline.

This study examined the relationship of trait anger to nocturnal blood pressure decline among Singaporean young adults. One hundred forty-nine participants (51 Chinese, 51 Malays, 47 Indians, 49.7% men) participated in 24-h ambulatory monitoring for blood pressure and hemodynamic measures. Significant interactions were obtained between ethnicity and trait anger for systolic blood pressure and mean arterial pressure such that trait anger was significantly and negatively related to nocturnal blood pressure decline for Indians whereas this was not true for Chinese or Malays. Significant sex x trait anger interactions were obtained for systolic blood pressure, diastolic blood pressure, and mean arterial pressure in which trait anger was negatively related to blood pressure decline for men but not for women. Overall the results suggest that trait anger is a significant factor affecting nocturnal blood pressure decline particularly among Indians and men.

Adult↗
PubMed2003

Cardiovascular reactivity of Singaporean male police officers as a function of task, ethnicity and hostility.

OBJECTIVE: This research examined hemodynamic processes in cardiovascular reactivity (CVR) as a function of task, ethnicity and trait hostility. METHOD: One hundred and fourteen male patrol officers from the Singapore Police Force participated in this experimental study. Trait hostility was measured using the interpersonal hostility assessment technique to derive a hostile behavior index (HBI). Heart rate, blood pressure and hemodynamic measures were taken while participants performed three tasks: mental arithmetic, number reading and anger recall (AR). RESULTS: AR elicited the greatest blood pressure, vascular and cardiac output reactivity. HBI scores were positively related to systolic blood pressure reactivity during AR for Malays whereas this was not true for Indians and Chinese. Across tasks Indians with high HBI scores appeared to be cardiac reactors whereas the reactivity patterns for Malays and Chinese were undifferentiated. Self-report of negative mood was not related to CVR. CONCLUSION: These results are consistent with the higher rates of coronary heart disease deaths among Indians as well as the higher rates for hypertension among Malays in Singapore.

Adult↗
PubMed2003

Job demands, decisional control, and cardiovascular responses.

The demand-control model for coronary heart disease was tested using ambulatory blood pressure monitoring. Male patrol officers (N = 118) wore ambulatory blood pressure monitors during 1 of their day shifts with readings taken every 30 min. Following each reading, officers completed a questionnaire using a handheld computer. Significant interactions were obtained between job demands and decisional control for heart rate and pressure rate product such that both variables were highest under conditions of high demand and low control. Main effects were obtained for control such that diastolic blood pressure and mean arterial pressure were significantly higher under conditions of low control. These results support the demand-control model and emphasize the importance of psychological control in cardiovascular responses.

Adult↗