Cigarette smoking is a worldwide public health challenge, ,Cigarette smoking is also a strong risk factor for musculoskeletal and cardiovascular disease, It is also well known that low and declining muscle strength is linked to increased smoking .Aims of this study was to examine the chronic effects of smoking on cardiovascular fitness in young and healthy male smokers. This study was carried out in university of hail ,physiotherapy lab, ,30male participant was recruited from university students of hail divided into two group 15 smoker (A) ,15 nonsmoker (B) .All subjects underwent a sub maximal Bruce treadmill test and their HR was recorded during, at peak, and after termination of exercise. Our study revealed that the resting HR was 5.3 bpm higher in smoker than in non smoker (P:0.0001)., data indicated that there was a significant difference found between young smokers and non-smokers regarding their sub-maximal HR values (P:0.0063)., where smokers had significantly higher HR values. also there was no difference between both groups regarding to recovery heart rate (P:0.56). Smoking was found to affect young smokers’ increasing HR at rest, slowing of HR increase during exercise, and impairing their ability to reach the age predicted HRmax., Also smoking was associated with an attenuated HR. . also Smokers had a higher resting HR and showed a higher HR response during sub-maximal exercise compared to Non smokers.