THE EFFECT OF A SINGLE ORAL DOSE OF L-ARGININE ON QUADRICEPS STRENGTH IN SMOKERS AND NON-SMOKERS: A NON-RANDOMIZED CLINICAL TRIAL.

Smoking is a major risk factor for the development of chronic obstructive pulmonary disease (COPD), which is thought to be caused by smoking in even 8 out of 10 cases. One of the first clinical signs in patients with COPD is reduced physical ability, which is usually attributed to reduced lung function, although a significant role is played by a disorder of the musculoskeletal system. The aim of the study was to examine differences in fitness and locomotor status between smokers and non-smokers, as well as the effect of oral administration of L-arginine on the strength of the quadriceps depending on smoking status. The study included 164 subjects, 84 non-smokers and 81 smokers not diagnosed with COPD. All subjects completed CAT and IPAQ questionnaires, and performed spirometry, 6-minute walking test and quadriceps strength testing without therapy and after oral administration of 500 mg L-arginine. The results showed that the increase in quadriceps strength after oral administration of L-arginine was not dependent on smoking status but was more pronounced in smokers who started smoking at an earlier age and who smoked more cigarettes, as well as a generally higher physical activity of non-smokers. These results could become relevant for recognizing the development of skeletal musculature hypotonus and hypotrophy in smokers who are prone to develop COPD.