Effects of tobacco smoking on the blood temperature during exercise.

By thermometry in mixed venous blood the thermal reactions to exercise programmes of different durations were studied in healthy volunteers before and after smoking. Pulmonary oxygen uptake (V02), arterio-venous oxygen difference (AVD) and heart rate (HR) were also measured. It was found that exercise-induced rise in blood temperature was considerably augmented after smoking. This effect was parallelled (and probably partly caused) by an increased heat production reflected by increased V02. During short-term exercise an accelerated rise in AVD might indicate that a centripetal redistribution of the total blood flow could have contributed to the thermal response by a reduced skin blood flow. During long-term exercise cardiac output and heart rate increased and the stroke volume decreased in response to smoking.