The effects of smoking on the respiratory system have already been examined in 50-year-old male members of the Japan Self-Defense Forces (JSDF). However, given the revision of the Health Promotion Act and other changes to the smoking culture in the intervening period, we have examined the effects of smoking in today’s environment. Pulmonary function test data, JSDF physical fitness test data (push-ups, sit-ups, and a 3,000-meter run), and chronic obstructive pulmonary disease (COPD) assessment test data (CAT score) were taken from 666 male members of JSDF, between 49 and 50 years of age, who underwent a medical checkup between April 2018 and March 2020. Results were compared between never smokers, ex-smokers, and smokers. Comparing never smokers and smokers revealed a significant difference in %FEV₁, FEV₁/FVC, %PEF, %V₅₀, %V₂₅, all items on the physical fitness test, and CAT score．The results suggest that smoking causes a decrease in pulmonary function and physical intolerance in the early stage of ageing.