PURPOSE: In this study we tried to investigate the effect of chronic smoking on respiratory muscle strength by determining and comparing maximal respiratory pressures (MRP) between a group of heavy male smokers (HSG) and a group of nonsmoking male controls (NSG), by determining maximal inspiratory and maximal expiratory pressures (MIP and MEP respectively).
METHODS: Fifteen healthy male heavy smokers (HSG) with a mean daily consumption of more than 25 cigarettes/day (aged 28±7.2 yrs. and a mean height of 176 ± 9.6 cm) and 15 healthy male non-smoking controls (aged 30 ±6.9 yrs. and a mean height of 178 ± 6.8 cm) were studied. All subjects had a negative medical history and physical examination, a normal chest X-ray and their spirometry was rated as within normal limits. They all had a recording of MRP with an electronic mouth pressure meter. Among 3 attempts the best value of MRP was recorded for the purpose of the study Comparisons were made by Student's t-test.
RESULTS: In HSG MIP was -101.4 ± 7.8 cm H2O (range 87 –116 cm H2O) while in NSG it was - 119.6 ± 6.4 cm H2O (range 106 - 133) (17.5% higher in the NSG, p< 0.01). On the other hand MEP in HSG was 127.5± 12.3 cmH2O (range 103 -153) while in NSG it was 132.7±11.4 cmH2O (range 96 –155, without statistically significant difference between the 2 groups).
CONCLUSION: Regular heavy smoking seems to be associated with rather lower maximal inspiratory pressures than those of non-smoking subjects without a statistically signifigant effect on maximal expiratory pressures and this might be independent of other consequencs on lung function.
CLINICAL IMPLICATIONS: It seems that heavy smoking subjects may exhibit a small reduction in inspiratory muscle strength compared to non-smokers. This fact may be one of the components of the reduced exercise tolerance of smokers compared with non-smokers.
DISCLOSURE: Stylianos Michaelides, No Financial Disclosure Information; No Product/Research Disclosure Information