Hypothetical explanations for the HRQL decreases may be initially sought in cigarette consumption itself. Smoking produces thousands of chemicals that are absorbed through the lungs. Some substances could have organic actions leading to asthenia, vitality loss, muscle disorders, or psychological derangement. Nicotine, for example, induces tachycardia and peripheral vasoconstriction. Decreases in peripheral blood flow may potentially interfere with tissue metabolism, impairing task performance. In addition, elevations of carbon monoxide and car-boxyhemoglobin may also impair tissue oxygenation. The findings that smoking may impair cardiorespiratory variables and decrease maximal oxygen uptake during exercise tests support this hypothesis. However, an additional comparison in our data between the SF-36 scores of heavy and moderate smokers with those of the light smokers did not show any significant difference between the groups. This suggests that the HRQL impairments of young smokers do not appear to be influenced by the smoking intensity, and argues against a functional cause for the present results.
Other explanations could be found in the smokers’ psychological profile. In this setting, the previous presence of depression, low self-esteem, and the predisposition to adopt a less healthy lifestyle could be responsible for starting smoking and the detected HRQL changes as well. In fact, it has been shown that the age at the first cigarette experience in adolescents is associated with reduced global life satisfaction. asthma inhalers
Previous studies have detected better quality-of-life scores for ex-smokers in comparison to current smokers. Although one study has found a relationship between poor scores of quality of life and cough and sputum production, other authors have emphasized that these findings could not be attributed exclusively to the improvement in respiratory symp-toms. Even though the available data strongly support the concept that smoking cessation is associated with improvements in HRQL, an alternative explanation may be possible. Smokers with best scores on quality of life would probably be those exhibiting more concern about their health status and, consequently, with greatest chances to be successful in smoking-cessation attempts. The study of serial HRQL measurements during smoking-cessa-tion protocols will certainly clarify these questions.
In conclusion, healthy, light-to-moderate smokers with a short smoking history show significant impairment in the physical and mental domains of HRQL in comparison to never-smokers. Hypothetical explanations for these findings include the action of tobacco-generated substances or intrinsic psychological features. A better elucidation of these aspects may provide useful information for planning smok-ing-cessation interventions.