FACTORS AFFECTING DIFFERENCES IN SUPINE, SITTING, AND STANDING HEART-RATE - THE ISRAELI CORDIS STUDY

Background: Measuring postural changes is among the simplest methods t o elicit basic cardiovascular responses from patients who should not b e subjected to treadmill stress testing. We attempted to clarify the i ndividual factors that may affect these changes in resting heart rate (HR). Methods: In a cross-sectional study, 6016 employees in Israeli i ndustries were screened during 1985-87 for cardiovascular disease risk factors (The CORDIS Study). Measures of resting HR (supine, sitting, and standing) were obtained from 5428 subjects. The association betwee n the HR differences for different postures and age, sex, height, body mass index, blood pressure level, health related habits, environmenta l temperature, and time of the day was analyzed. Results: The differen ce in HR between supine and standing position was found to be greater among women than men (12.7 vs, 11.6%, p < 0.03). It was independently positively associated with height (p < 0.0001), cigarette smoking (p < 0.0001), and coffee drinking (p < 0.001), and inversely associated wi th age (p < 0.002), blood pressure level (p < 0.0005), and physical ac tivity at work (p < 0.0001). Conclusion: The interindividual variabil ity in HR response to different postures is partially explained by ind ividual variables such as age, sex, height, blood pressure level, and health-related habits.