CLINICAL INVESTIGATION Predictors of systolic blood pressure response to treadmill exercise: the Lipid Research Clinics Program Prevalence Study

We used multiple linear regression to study predictors of systolic blood pressure response (SBPR), i.e., the increase in pressure above baseline after 3, 6, and 9 min of treadmill exercise, in 4262 men and women. Predictors considered were usual SBP, the difference (A SBP) between resting SBP and SBP immediately before exercise, age, education, obesity index, alcohol consumption, cigarette smoking, preexercise heart rate and, in women, gonadal hormone use. In men, age, obesity index, and cigarette sr oking were positively associated with SBPR and in women 20 to 49 years old, age, obesity index, an' alcohol consumption were positively associated with SBPR. In women 50 years old or older, usual SBP was negatively associated with SBPR. In both men and women a larger A SBP was associated with a smaller SBPR. These results help explain the considerable variation in SBPR, and the A SBP results suggest that potential SBPR may, to certain extent, have a specific, finite range. The similarity of predictor variables for SBPR to predictor variables for hypertension is concordant with the previous observation that a high SBPR may foreshadow subsequent hypertension. Circulation 68, No. 2, 225-233, 1983. RECENTLY there has been increasing interest in the systolic blood pressure response (SBPR) of patients undergoing clinical exercise testing on motor-driven treadmills or cycle ergometers. This interest stems from findings in both clinical and epidemiologic studies that the substantial variation in the magnitude of From the Department of Community and Family Medicine, School of Medicine, University of California, San Diego; Department of Medicine, Stanford University Medical Center, Stanford; the Departments of Biostatistics and Epidemiology, School of Public Health, University of North Carolina, Chapel Hill; and the Department of Medicine, University of Oklahoma, Oklahoma City. Supported by NHLBI contracts NOL-HV1-2156-L, NO1-HV1-2160L, NOl-HV2-2914-L, NOI-HV3-0010-L, NO1-HV2-2913-L, NOIHV1-2158-L, NOI-HV1-2161-L, NO1-HV2-2915-L, NO1-HV22932-L, NO1-HV2-2917-1, NO1-HVI-2157-L, NO1-HV1-2243-L, NOl-HVl-2159-L, NO1-HV3-2961-L, and NO1-HV6-2941-L. Address for correspondence: Janet Bungay, Lipid Metabolism Branch/DHVD, National Heart, Lung and Blood Institute, National Institutes of Health, Federal Bldg., Rm. 401, Bethesda, MD 20205. Received Nov. 23, 1982; revision accepted April 14, 1983. Dr. Criqui is a recipient of a Research Career Development Award (HL 00946) from the National Heart, Lung and Blood Institute. Vol. 68, No. 2, August 1983 SBPR among healthy men and women is not explicable by resting blood pressure, age, or sex,1-3 the finding that SBPR is predictive of subsequent hypertension,4 and the observation that labile hypertension may be as important as stable hypertension in the prediction of subsequent cardiovascular events.5 In addition, to our knowledge no study has been published that has evaluated the independent relationship of SBPR to multiple personal charactenrstics such as obesity, alcohol consumption, cigarette smoking, regular exercise, educational level, or gonadal hormone use (in women), although all of these have been reported to have some relationship to resting blood pressure.6'7 As part of the Lipid Research Clinics Progam Prevalence Study we studied SBPR to treadmill exercise in men and women in nine North American populations and evaluated the relationship of SBPR to "usual" SBP, the difference between resting SBP and SBP immediately before exercise (A SBP), age, sex, level