Smoking and Sport

Effects of tobacco use on physical sport capacity

Even though, there is no other toxic agent worldwide, causing more cancer and death, smoking is still common among men and women. In 2007 46 million U.S. adults were current smokers and despite all anti-smoking campaigns 20% of all high school students in the United States were current cigarette smokers (11)
The effects of smoking on the human body can be separated in acute and chronic:

Short term effects
Smoking just one cigarette is enough to impair functions that are essential for our physical capacity:
1. By taking a drag, the inhaled nicotine gets access to the body's bloodstream, causing an increase in noradrenaline excretion, putting our body on alert - "silent-stress" (2). The impulse generator of our heart (sinoatrial node), the blood pressure detectors at our neck (carotid sinus) and the vascular tone (vasoconstriction) are affected by nicotine. ear about 10 beats/min for over 45min, accompanied by an increase of blood pressure. Those effects result in a higher oxygen-demand of the myocardial muscle.
2. Further, nicotine causes an earlier onset of fatigue. On the one hand, this is a result of the increased metabolic rate, with a preterm depletion of our endogenous glycogen storage. On the other, it is caused by a down-regulation of beta-receptors of the heart, due to the chronically increased concentrations of circulating noradrenaline (3).
3. At rest metabolic changes are accompanied by an increase of blood glucose and fatty acids even though they are not needed for energy supply. This circumstance increases the risk for arteriosclerosis (2).
4. The sensation of hunger is suppressed (4). This is why smokers usually gain 2-2.3kg body fat after they stopped smoking.
5. The inhaled carbon monoxide (CO) combines with hemoglobin of the red blood cells and forms a complex called carboxyhemoglobin, which is ineffective in delivering oxygen. Therewith the cardiac output needs to increase for transporting the same amount of oxygen within the same time. This is associated with an increased oxygen demand of the heart. For exemplification: One cigarette equates to a sudden climb up to the height of 1300m above sea level (5).
6. A partially depolarization of chemo receptors of the carotid body changes the responding behavior to changed CO2 values, causing an increased respiratory frequency (2).

Long term effects
About 40-60 chemical agents out of 4000 cigarette ingredients are known to cause cancer. Usually people are worried about lung cancer, but far more diseases are known to be associated with the inhalation of tobacco smoke.
1.

Arteriosclerosis: The increased carbon monoxide concentration causes an insufficient oxygen supply of the vascular walls. Especially in addition with an elevated cholesterol level and mutagenic substances, this will lead to a stenosis of the vessel lumen with associated ischemia of different organs (angina pectoris, myocardial infarction, stroke, placenta infarction etc.) (5). Depending on the extend of the artherosclerotic changes, an overall reduction of the physical performance will set in.
2. Recurrend infections of the upper airways are frequently observed in smokers, due to the chronic disturbances of the ciliated epithelium (6). These infections often require prolonged rest from training.
3. Reduced muscle growth and enhanced muscle catabolism: Smoking increases the activity of myostatin and MAFbx. Whereas myostatin inhibits normal muscle growth, MAFbx is known to induce muscle atrophy (7). In addition to that, anaerobic performance that is important for resistance training, is also impaired by nicotine consumption (8).
4. Impaired left and right ventricular diastolic function in chronic smokers (9).
5. Gastric ulcer
6. Increased risk for osteoporosis and degeneration of the intervertebral discs
7. Renal carcinoma (smoking doubles the risk)
8. Esophagus carcinoma
9. Crohn's disease
10. Laryngitis and cancer of the throat (larynx carcinoma)
11. Cervix cancer

On average smoking shortens lifespan about 7.5 years!
According to Taylor et al. (10), sport is able to produce a positive effect on cigarette cravings. This was shown by a systematic review of studies between 1983-2006. The researchers concluded that this effect was independent of intensity of training. Rather exercise itself seems to activate similar brain regions like smoking does and is therefore able to reduce withdrawal symptoms.

Reference List

(1) Statistisches Bundesamt Deutschland. Pressemitteilung Nr.238 vom 30.05.2005. Internet . 2005. Wiesbaden, Statistisches Bundesamt.
Ref Type: Online Source
(2) Lüllmann H, Mohr K. Taschenatlas der Pharmakologie. 4 ed. Stuttgart: Georg Thieme Verlag; 2001.
(3) Huie MJ. The effects of smoking on exercise performance. Sports Med 1996; 22(6):355-359.
(4) Perkins KA, Epstein LH, Stiller RL, Fernstrom MH, Sexton JE, Jacob RG et al. Acute effects of nicotine on hunger and caloric intake in smokers and nonsmokers. Psychopharmacology (Berl) 1991; 103(1):103-109.
(5) Riede UN, Schäfer HE. Allgemeine und spezielle Pathologie. 4 ed. Stuttgart: Georg Thieme Verlag; 2001.
(6) Dye JA, Adler KB. Effects of cigarette smoke on epithelial cells of the respiratory tract. Thorax 1994; 49(8):825-834.
(7) Petersen AM, Magkos F, Atherton P, Selby A, Smith K, Rennie MJ et al. Smoking impairs muscle protein synthesis and increases the expression of myostatin and MAFbx in muscle. Am J Physiol Endocrinol Metab 2007; 293(3):E843-E848.
(8) Fukuba Y, Takamoto N, Kushima K, Ohtaki M, Kihara H, Tanaka T et al. Cigarette smoking and physical fitness. Ann Physiol Anthropol 1993; 12(4):195-212.
(9) Karakaya O, Barutcu I, Esen AM, Kaya D, Turkmen M, Melek M et al. Acute smoking-induced alterations in Doppler echocardiographic measurements in chronic smokers. Tex Heart Inst J 2006; 33(2):134-138.
(10) Taylor AH, Ussher MH, Faulkner G. The acute effects of exercise on cigarette cravings, withdrawal symptoms, affect and smoking behaviour: a systematic review. Addiction 2007; 102(4):534-543.
(11) CDC. Tobacco Use - Targeting the Nation's Leading Killer: At a Glance. Internet , 1-4. 2010. Atlanta, National Center for Chronic Disease Prevention and Health Promotion.
Ref Type: Online Source