Smoking has a detrimental impact on cardiovascular fitness, as it reduces the efficiency of the heart and lungs. Nicotine and other chemicals in cigarettes constrict blood vessels and decrease oxygen delivery to tissues, impairing physical performance. Furthermore, smoking can lead to the development of chronic respiratory diseases, limiting endurance and overall fitness. Quitting smoking can drastically improve cardiovascular health, leading to better exercise tolerance, enhanced fitness levels, and reduced risks of heart disease and stroke. Thus, abstaining from smoking is crucial for maintaining optimal cardiovascular health.