Smoking status and physical fitness during initial military training

Abstract

Background: Habitual smoking is prevalent in military populations, but whether smoking status influences physical fitness development during training is not clear. Aims: We investigated the effect of smoking status on physical fitness parameters during initial British Army Infantry training. Methods: Routine measures of physical fitness (2.4 km run time and maximum number of press ups and sit ups in two minutes) were obtained in 1,182 male recruits (mean ± SD: age 20 ± 3 y, body mass 70.6 ± 9.8 kg, height 1.77 ± 0.07 m; 58% smokers) at weeks 1, 14 and 24 of initial military training. A linear mixed model was used to identify differences in performance between smokers and nonsmokers over time. Results: Non-smokers performed significantly better than smokers in all performance tests (P0.05). Run performance improved by 7% in non-smokers (estimated marginal means with 95% confidence limits; 612 (608-616) s to 567 (562-572) s) and 8% in smokers (622 (619-625) s to 571 (568-575) s). Press up performance improved by 18% in non-smokers (48.3 (47.1-49.4) to 57.0 (55.6-58.3)) and 23% in smokers (44.1 (43.2-45.1) to 54.5 (53.3-55.6)) and sit up performance by 15% in non-smokers (57.3 (56.3-58.2) to 66.0 (64.9-67.2)) and 18% in smokers (53.8 (53.0-54.6) to 63.3 (62.3- 64.3)). Conclusions: Smokers exhibited lower muscular and cardiorespiratory endurance performance than non-smokers. Unexpectedly however, no significant differences in improvement in performance indices were demonstrated between smokers and non-smokers during military training.