International Journal of Psychophysiology 49 (2003) 99–110 0167-8760/03/$ - see front matter  2003 Elsevier Science B.V. All rights reserved. doi:10.1016/S0167-8760Ž03.00082-5 Cardiovascular reactivity of Singaporean male police officers as a function of task, ethnicity and hostility Yong Peng Why , George D. Bishop *, Eddie M.W. Tong , Siew Maan Diong , a a, a a Hwee Chong Enkelmann , Majeed Khader , Jansen Ang a b b Department of Social Work and Psychology, National University of Singapore, 11 Law Link, Singapore 117570, Singapore a Police Psychological Unit, Singapore Police Force, Singapore, Singapore b Received 14 August 2002; received in revised form 20 March 2003; accepted 1 April 2003 Abstract 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.  2003 Elsevier Science B.V. All rights reserved. Keywords: Ethnicity; Hostility; Impedance cardiography; Hemodynamic processes; Singapore; Anger; Cardiovascular reactivity Abbreviations: AR, anger recall; BMI, body mass index; BSA, body surface area; CHD, coronary heart disease; CVR, cardiovascular reactivity; IHAT, interpersonal hostility assess- ment technique; HBI, hostile behavior index; MA, mental arithmetic; NR, number reading; SI, structured interview; S.D., standard deviation; S.E., standard error. *Corresponding author. Tel.: q65-6874-6415; fax: q65- 6778-1213. E-mail address: george_bishop@nus.edu.sg (G.D. Bishop). 1. Introduction Over the past few decades empirical evidence has accumulated supporting the importance of anger yhostility as a risk factor in coronary heart disease (CHD)(Barefoot et al., 1983, 1989; Shek- elle et al., 1983). A recent meta-analysis has shown that the hostility–CHD relationship is a reliable one that remains strong even after traditional CHD risk factors have been controlled for (Miller et al., 1996).