Cardiovascular Effects of Cold Pressor Tests, 40° Head-up Tilt, and Smoking on Smokers and Non-smokers

Cardiovascular responses to various stress tests have been studied in 13 nonsmokers, 16 moderate (20 cigarettes per day) and 13 heavy (40 cigarettes per day) smokers before and after cigarette smoking. Intra-arterial, pressure, ECG, respiration, and skin temperature were continuously monitored and recorded on tape. Dye dilution cardiac outputs were measured in some of the subjects. The analog data were analyzed on a digital computer using A-D conversion. Blood pressure, heart rate and cardiac output were not different in smokers and nonsmokers before and after smoking. Hyperreactor response to cold immersion by Hines' criteria was extremely frequent (30 percent to 58 percent) in all subjects with the use of continuous pressure measurement. A composite of maximal response, time of return and the area under the pressure curve is suggested for better definition of the cold pressor response. Presyncopal reactions during 40° head-up tilt were more frequent in heavy smokers after smoking.