Effect of smoking on the central circulation at rest and during exercise as studied by radiocardiography

The pulmonary vessels are the first target of tobacco smoke in the circulatory system, but the functional changes occurring in the pulmonary circulation are poorly understood. Hence 46 volunteers were studied by radiocardiography under the following conditions: 1. At rest before and after smoking 2 cigarettes (15 men); 2. After repeated ergometer exercise (5 min, 100 W) with and without smoking (13 men); and 3. Control experiments under the corresponding conditions without smoking (18 subjects). A significant increase occurred in heart rate, cardiac output and systolic arterial blood pressure after smoking when at rest, but an almost significant decrease in pulmonary dispersion volume , whereas the heart rate and pulmonary capillary pressure attained significantly higher values after than before smoking in the exercise tests, with a significant decrease observed in stroke volume, pulmonary blood volume and pulmonary dispersion volume. It is concluded that smoking impairs physical performance, increases pulmonary capillary pressure and reduces pulmonary blood volume and probably the number of open capillaries.