Smoking tobacco is a well-known health hazard, which often leads to respiratory and cardiovascular diseases. However, smoking can impair physical fitness long before these chronic diseases arise. Even limited or occasional tobacco use can have significant deleterious effects on athletic performance. These effects are due to the complex mixture of chemicals in cigarette smoke, including multiple toxic carcinogens. While smoking is far less prevalent among elite athletes compared to the general public, it is not uncommon -- despite the negative effects on physical performance.
Heart and Respiratory Rate
Tobacco contains nicotine, the compound that provides the stimulant effect of cigarette smoking. For most people, nicotine provides a calming effect, but nicotine actually excites the central nervous system. When the central nervous system is stimulated by nicotine, the heart and breathing rate accelerate. An increased heart rate before exercising will alter an athlete's target heart rates and decrease the maximum heart rate.
Reduced Exercise Tolerance
An athlete's ability to tolerate exercise is decreased by smoking. Not only is the length of time an athlete is able to exert himself decreased, but his maximal effort is also significantly lower. The authors of a research study report published in the October 2007 issue of "European Journal of Cardiovascular Prevention and Rehabilitation" reported that exercise tolerance is impaired and and the duration of time young, health men who smoke are able to tolerate exercise is significantly shorter compared to nonsmokers.
Blood Pressure and Nitric Oxide
Smoking increases blood pressure. While the initial effect of nicotine causes dilation and an increase in blood flow -- especially to the brain -- the net result is the constriction of blood vessels (see reference 4). The constriction of the blood vessels will decrease the amount of oxygen delivered to the muscles, leading to premature exhaustion.
Blood vessels dilate and relax in the presence of nitric oxide; smoking significantly decreases nitric oxide formation capability, causing constriction of the blood vessels and a decrease in blood flow. This decrease in blood flow is disadvantageous, especially for athletes. Nitric oxide released while exercising helps the body accommodate for the increased demand for oxygen and the elimination of lactic acid and carbon dioxide.
Lung Elasticity and Capacity
Habitual smoking will eventually lead to a loss of lung elasticity and a decrease in lung volume and oxygen capacity due to inflammation and degradation of elastic tissue. Severe loss of elasticity is referred to as emphysema. However, a decrease in elasticity can occur long before the presentation of emphysema symptoms. A decrease in lung capacity will eventually cause an athlete to feel winded, or out of breath, with less effort.
Long Term Effects of Cigarettes
In addition to the athletic performance-diminishing effects of smoking, there are many long-term consequences of smoking cigarettes. Lung cancer is the disease most commonly associated with smoking. The carcinogens present in tobacco smoke cause cancer. According to a study in "Chest Journal," nearly all deaths by lung cancer are caused by cigarette smoking (see reference 5).
The decrease in nitric oxide formation noted previously is largely responsible for the progression of atherosclerosis. Not only does nitric oxide relax the blood vessels and allow for an increase in blood flow, nitric oxide also protects the lining of the arteries; without the nitric oxide, the artery walls are prone to damage and hardening, which leads to atherosclerosis (see reference 4).