People who are current or former smokers may be less likely to develop or die from lung cancer when they are more physically fit.
Researchers gave treadmill tests to 2,979 men - 1,602 who were former smokers and 1,377 who were current smokers - to assess their "cardiorespiratory" fitness, or how easily the circulatory and respiratory systems can supply oxygen to muscles during physical exertion.
According to Reuters, researchers followed the men for an average of 11.6 years; during this period, 99 participants were diagnosed with lung cancer and 79 of these people died from cancer.
Lead study author Baruch Vainshelboim said: "Both former and current smokers can significantly reduce their risk of developing and dying from lung cancer by achieving higher cardiorespiratory fitness."
"Aerobic exercise at moderate to vigorous intensity such walking, jogging, running, biking, or elliptical for 20 to 30 minutes three to five times a week can improve cardiorespiratory fitness," Vainshelboim said by email.
Lung cancer remains the most common cancer worldwide, with more than 2 million new cases and 1.8 million deaths a year, researchers note in the American Journal of Preventive Medicine. Tobacco is the single most important risk factor for developing and dying from lung cancer.
Eliminating low cardiorespiratory fitness as a risk factor could prevent about 11 percent of lung cancer diagnoses in former smokers and roughly 22 percent of cancer deaths in current smokers who develop lung cancer, the study authors estimated.