It is a known fact that smoking over time can cause lung damage and emphysema, but it also can have adverse effects on muscle endurance, increase the risk of injury and diminish physical performance. Those facts are particularly important to the U.S. military since a 2008 Department of Defense survey found that almost one-third of active-duty service members smoke, with an even higher number of smokers among troops in combat zones.

Smoking can cause immediate effects on health, including increasing injury risk and diminishing physical performance, but it also can affect soldiers’ muscle endurance as they age, according to studies by the U.S. Army Public Health Command (USAPHC).

Oxygen is essential for muscle function, especially during exercise, but nicotine reduces oxygenated blood flow. Soldiers who smoke have decreased stamina and performance, and they become fatigued more quickly. Smoking also reduces muscle endurance because the heart must work harder to pump blood through clogged blood vessels, which can lead to a greater chance of muscle injury.

Other USAPHC studies show that soldiers who smoke have can have a 30 percent reduction in night vision for those with normal eyes and 50 percent reduction for those wearing corrective lenses. Smoking reduces mental sharpness, and because smoking reduces blood flow to the extremities, it increases the risk of heat and cold injuries.