PROGRAMME SCIENTIFIQUE - Oxygen Club of California

OP29
Complex relationships between smoking, physical activity and oxidant stress :
Smoking negates the beneficial effects of exercise training in human.
Denis Blache
Centre de Recherche Inserm UMR 866, Faculté de Médecine, 7 boul. Jeanne d’Arc 21079 Dijon France
e-mail : dblache@u-bourgogne.fr
Amongst several lifestyle habits physical exercise and smoking have a significant influence on the risk of
major vascular thrombotic events. These factors have in common to tackle the redox balance. It is
wellknown that physical exercise produces reactive oxygen species (ROS) that could be exacerbated
during vigorous exercise. However, regular exercise without exhaustion is associated with a reduced ROS
production and with an overall decreased risk of cardiovascular diseases. In previous studies, we have
shown that cigarette smoking is associated with increased platelet activation and impaired redox status in
humans. Smoking has also been reported to release large amounts of ROS which were proposed to
represent a potential mechanistic link between cigarette smoking and cardiovascular diseases. The
increased oxidant stress observed in smokers may be due to the lower blood antioxidants usually
observed in smokers. Numerous key parameters involved in pro-atherothrombotic effects of smoking
such as fibrinogen, interleukin-6, platelet activation, LDL-cholesterol, oxidant stress biomarkers, etc…
might be favorably modified by regular endurance exercise. Therefore, the commonly accepted idea that
exercise would normalize smoking-induced alteration of biological parameters has not received
experimental-based evidence. On the contrary, recent work clearly indicated that postprandial oxidant
stress was reported to be exacerbated in cigarette smokers.
In the present study, we thus compared oxidant stress biomarkers in 146 healthy subjects before and after
a 20-week exercise training program. Basal levels of antioxidants and oxidant stress markers were altered
between non-smokers and smokers. These data were compatible with an increase in oxidized lipids and
proteins in smokers. Exercise improved several parameters in non-smokers although it did not modify the
LDL oxidation parameters. Significantly increased resistance was observed in the free radical–induced
hemolysis in non-smokers. We found a general improvement in the antioxidant status following the
exercise training session in non-smoking subjects. This effects was not observed in smokers specially in
men. From our data, we can conclude that smoking negates the beneficial effects of exercise training.