Cigarette smoking following a prolonged mental task exaggerates vasoconstriction in glabrous skin in habitual smokers

In the present study, to test the hypothesis that cigarette smoking and physical exercise induce different influences on peripheral vasomotor control after mental stress, we examined the physiological responses, including skin vasomotor responses, to smoking and exercise in six healthy smokers. The smokers performed 2 hr of mental arithmetic tasks (MT) followed by smoking or bicycle exercise (108 +/- 7W) for 10 min or a time control (i.e., rest without smoking) under thermally comfortable conditions (25 degrees C). Skin blood flow (laser-Doppler flowmetry) was monitored at glabrous (palm) and nonglabrous (forearm, forehead) sites. Cutaneous vascular conductance (CVC) was evaluated from the ratio of blood flow to mean arterial pressure (MAP). The prolonged MT increased MAP from 77.7 +/- 2.7 mmHg to 86.0 +/- 3.0 mmHg and reduced CVC in the palm by 27.4 +/- 5.6%, but did not change those in the forearm and forehead. Smoking after MT further decreased CVC in the palm, and the smoking-induced reduction in CVC persisted until 20 min after smoking. Meanwhile, CVC in the forearm and forehead transiently and minimally decreased during smoking. Exercise after MT increased CVC at the three sites, and the exercise-induced elevation of CVC in the palm persisted until 30 min after exercise. In the time control experiments, each variable remained unchanged throughout the recovery period of MT. It was suggested that smoking causes additional vasoconstriction in glabrous skin after prolonged MT, while the exercise-associated vasodilator effect counteracts the vasoconstrictor action of MT. We speculate that long-term mental stress and smoking behavior may synergistically develop chronic stress-induced vascular dysfunction, and the stress-related disorders may be reduced by habitual enforcement of moderate exercise.