Nicotine, the substance in tobacco that causes people to become addicted to smoking, harms people in many ways. Smoking, in fact, causes 443,000 premature deaths in the United States annually, reports the American Cancer Society. As bad a habit as smoking is, though, "It's a particularly bad idea to smoke within two hours of beginning to exercise," because of nicotine's effect on your body, according to "Dr. Dean Ornish's Program for Reversing Heart Disease."
Nicotine's Impact
Nicotine damages blood vessels, brains, hearts and lungs, according to the college textbook, "An Invitation to Health." It harms blood vessels by causing them to constrict so much that smokers' blood pressure increases. It harms brains by stimulating them within eight seconds of smoking and then triggers the release of tranquilizing chemicals. It harms hearts by increasing heart rates so much that smokers' risk of sudden cardiac arrest increases dramatically. Smokers are 20 times more likely to have a heart attack than nonsmokers. Nicotine also harms lungs, reducing the body's ability to bring in oxygen and impairing the respiratory system. Smokers are 18 times more likely than nonsmokers to die of lung disease and are more apt to be breathless and have a chronic cough.
Exercise's Impact
In the long run, exercising reduces your risk of premature death of all causes, according to Dr. Dean Ornish. Exercising has a particularly beneficial impact on your risk of cardiovascular disease and stroke because it increases the good blood cholesterol in your body and lowers your blood pressure. In the short run, though, exercise can be risky. You need to increase your heart rate during exercise to improve your fitness enough to reduce your risk of premature death, heart attack and stroke. An increased heart rate dramatically increases your risk of sudden death. In fact, you're seven times more likely to die while jogging than while doing sedentary activity, Ornish wrote.
Bad Combination
The short-term impact of nicotine and exercise on your body can be a deadly combination, Ornish wrote. Nicotine's impact on your heart rate, blood vessels and lungs is particularly profound for at least two hours after your most recent cigarette. Since nicotine and exercise both increase your heart rate, your heart rate is more likely to be unsafe enough to trigger a heart attack if you smoke within two hours of exercising. Your exercise heart rate should not be higher than 220 heartbeats per minute, minus your age. Nicotine's negative impact on oxygen supply is also more detrimental if you exercise shortly after smoking because your body needs more oxygen while you exercise. A lack of oxygen can also cause a heart attack.
After Exercise
The impact of nicotine can make the period after your exercise very dangerous. Without nicotine in your system, approximately 60 percent of your blood is below your waist, according to exercise expert Dr. Kenneth Cooper. Stopping exercise suddenly rather than slowing down gradually can cause your blood to remain below your waist rather than circulating to your brain and heart. This can increase your risk of a heart attack or stroke. If you smoked recently, nicotine's constriction of your blood vessels can increase your risk of a heart attack or stroke even more, wrote Cooper.
References
- American Cancer Society: Cancer Prevention Facts & Figures 2009
- "An Invitation to Health"; Dianne Hales; 2010
- "Dr. Dean Ornish's Program For Reversing Heart Disease"; Dr. Dean Ornish; 1996
- "Controlling Cholesterol The Natural Way"; Dr. Kenneth Cooper and William Proctor; 1999
