Smoking influences physical fitness and endurance negatively by impairing lung function and cardiovascular health. The toxic substances in cigarettes damage lung tissue, leading to reduced oxygen uptake and decreased overall stamina. Smokers may experience shorter exercise durations, lower energy levels, and accelerated fatigue during physical activities. Additionally, smoking hinders recovery by affecting circulation and nutrient delivery to muscles. Quitting smoking can result in significant improvements in fitness levels and overall health, making it an essential step for those looking to enhance their physical performance and longevity.