<sec> <title>Objectives</title> <p>To investigate the effect of smoking upon cardiopulmonary function, maximal oxygen uptake, and obesity index, in middle-aged and older workers to propose guidelines on healthcare for these age groups.</p></sec> <sec> <title>Methods</title> <p>This study analyzed medical data from 2,753 white-collar workers aged 50 years or older from workplaces located in Seoul, South Korea. Blood pressure (BP), resting heart rate, maximal oxygen uptake (VO₂max), and body mass index (BMI) of each subject were measured. The collected data were analyzed using SPSS 21.0.</p></sec> <sec> <title>Results</title> <p>In the smoking group BP and resting heart rate were significantly higher than in the non-smoking and smoking-cessation groups (<italic>p</italic> < 0.05). In addition, VO₂max was lower in the smoking group compared to the other 2 groups. BP closely correlated with resting heart rate, abdominal fat ratio, and BMI. BMI was the highest in the group that stopped smoking and, BMI and abdominal fat ratio negatively correlated with VO₂max.</p></sec> <sec> <title>Conclusion</title> <p>Smoking increases the risk of cardiopulmonary disease but obesity may be caused by stopping smoking. Therefore, healthcare guidelines on smoking cessation should also include nutritional advice.</p></sec>