Smoking and The Human Body

Smoking is a bad habit which plagues the young, as well as the old. It is the largest source of preventable mortality in North America1. Not only does smoking lead to an early grave, but it can also influence one\'s daily life. Many studies have revealed links between smoking and reduced endurance capacity2. Nicotine, the addictive agent found in cigarettes, can also be used to control weight gain. Both of these factors can have considerable effect on the sporting world. There have been many studies done, indicating that if you smoked, you did less physical activity. It has also been shown that the more you smoke, the less activity you do. In one experiment done on smokers and non-smokers, the subjects were tested while running a marathon. The experimenters took a large group of mainly non-smokers and army conscripts and measured their performance. It was found that the distance covered in the race was inversely related to daily cigarette consumption3. That is, the more you smoked, the less distance you ran. The longer the participant in the race had been smoking, the worse he/she performed. For example, the average non-smoker could cover 2613 meters in 12 minutes, while a smoker of less than 2 years who smoked 21+ cigarettes a day could only cover 2284 meters. A smoker of more than 4 years who smoked 21+ cigarettes a day could only cover 2188 meters4. These results show how performance decreases the more a person smokes in their lifetime. An experiment performed by Robert C. Klesges et al. found that although smokers did fewer sports, and leisure time activities, they did the same amount of anaerobic activities5. The study also found that smokers had the same energy intake as non-smokers, indicating that eating habits were not a factor in the fitness levels. Smokers average 30-35 kcal per day less of high intensity activity than non-smokers6. This reduced aerobic physical activity can be attributed to the fact that smoking causes an increase in carboxyhemoglobin which decreases the oxygen carrying capacity of the blood, which would cause relative hypoxia in tissues and lead to reduced performance during maximal physical exertion7. Since smoking is so detrimental to the oxygen transport system, it effects endurance capacity more than any other element of fitness such as muscle strength or speed. This must be taken in consideration if an athlete wishes to smoke. No longer will his or her muscle strength be a factor. Instead, their decreased ability to carry oxygen will severely limit their performance. Many sports and activities require the athlete to do notable amounts of work and expend a fair amount of energy. When an athlete smokes, they will not be able to get the required oxygen to the necessary parts of the body, and therefore will not perform as well. It has been proven that even if you have smoked, when you quit smoking your levels of physical activity will increase8. When taking a glimpse of all the top athletes in the world, it can be noted that none of them are frequent tobacco product users. Another aspect of smoking and the human body is the effect of nicotine on body weight. Nicotine, the drug found in cigarettes, is usually what tends to get smokers addicted to tobacco products. Through many different experiments, it has been shown that smokers tend to weigh less than non- smokers9. These tests were done not only by measurement of weight, but by multiple skinfold thickness assessments. In a study done on rats, it was determined that nicotine exposed rats had significantly less carcass fat, suggesting that nicotine effects fat stores. The more nicotine which was given, the less fat the rats had. It was hypothesized that nicotine effected these fat stores was by altering key enzymes in the regulation and uptake of triglycerides such as adipose-tissue lipoprotein lipase10. When dealing with humans, one study found that smokers had 2.8% lower total body fat than non-smokers11. During the process of this test it was noted that smokers consumed more calories per day than non-smokers and much more sucrose than non-smokers. The researchers involved in this experiment devised that nicotine could increase the metabolic rate. A third and more recent study confirmed