Smoking significantly diminishes lung capacity by damaging lung tissue, leading to reduced airflow and impaired oxygen exchange. This can result in decreased physical performance, making aerobic activities more strenuous. Over time, it increases the risk of chronic obstructive pulmonary disease (COPD), reducing overall stamina and athletic abilities. Smokers may find themselves easily fatigued during exercise, as the reduced oxygen supply adversely impacts physical endurance and recovery rates. Quitting smoking can improve lung function and enhance performance levels, benefiting overall health in the long run.