Smoking status and physical fitness during initial military training

Habitual smoking is prevalent in military populations, but whether smoking status influences physical fitness development during training is not clear. To investigate the effect of smoking status on physical fitness parameters during initial British Army infantry training. Routine measures of physical fitness (2.4-km run time and maximum number of press ups and sit ups in 2 min) were obtained in male recruits at weeks 1, 14 and 24 of initial military training. A linear mixed model was used to identify differences in performance between smokers and non-smokers over time. Among 1182 study subjects (mean ± SD: age 20 ± 3, body mass 70.6 ± 9.8 kg, height 1.77 ± 0.07 m; 58% smokers), non-smokers performed significantly better than smokers in all performance tests (P <0.01), but rates of improvement during training were similar (P > 0.05). Run performance improved by 7% in non-smokers (estimated marginal means 612-567 s) and 8% in smokers (622-571 s). Press up performance improved by 18% in non-smokers (48.3-57.0) and 23% in smokers (44.1-54.5) and sit up performance by 15% in non-smokers (57.3-66.0) and 18% in smokers (53.8-63.3). 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.