Abstract
To assess the acute effect of cigarette smoking on physiologic response to graded
exercise, eight physical education students were tested. The protocol included running
on a treadmill for 5-min periods at the speed of 6, 8, 10, and 12 km/h. Each subject
performed the exercise twice 1 week apart, once after abstaining from smoking for
24 h and once immediately after smoking two cigarettes. The following measurements
were performed at each work load: HR, oxygen consumption, tidal volume, breathing
frequency, pulmonary ventilation, and blood lactate. Running velocity corresponding
to 4 mM lactate and to 170 HR were calculated. The average HR was higher after smoking
at rest and at all work loads tested (P < 0.05). The average V̇O2 was lower after smoking at all work loads above 6 km/h (P < 0.05), and V̇E/V̇O2 was significantly higher (P < 0.001) during smoking at all work loads above 6 km/h. No changes were found in
the other parameters measured. No difference was found in the calculated work load
corresponding to 4 mM blood lactate or 170 HR. It is concluded that although the acute
effect of smoking two cigarettes by subjects accustomed to smoking does not dramatically
affect their work capacity, it does significantly change their physiologic response,
manifested by a higher HR, lower V̇O2, and lower breathing efficiency.
Key words
smoking - physiologic response - graded exercise lactate - heart rate - V̇O2
