Smoking is the leading preventable cause of death in the United States, contributing to chronic bronchitis, emphysema, heart disease, stroke and several types of cancer. The good news is that if you quit, your increased risk for most of these diseases will drop and, eventually, disappear altogether. Here is a timeline of ways the body heals itself after you stub out your last cigarette.
After 2 hours
About two hours after you quit the habit, your pulse rate decreases and blood pressure drops. Nicotine in cigarettes stimulates the corpse to produce adrenaline. This ‘fight or flight’ hormone causes the heart to beat faster. Nicotine also raises blood pressure by causing the walls of blood vessels to constrict. Increased heart rate and blood pressure mean that smokers’ hearts have to work harder than non-smokers’ hearts.
After 8 hours
Eight hours after you stop smoking, oxygen levels in the blood return to normal. Tobacco smoke contains up to 5% carbon monoxide. When you smoke, this chemical enters the bloodstream and attaches to hemoglobin in the red blood cells, decreasing the blood’s ability to carry oxygen to the tissues. After you finish your final cigarette, carbon monoxide levels begin to drop and your circulation improves. You may notice that your hands and feet feel warmer as more oxygen is carried to the extremities.
After 48 hours
Within two or three days without a smoke, your ability to smell and taste will begin to improve. Olfactory nerves located in the back of your nose carry odor signals to your brain. Smoking compensation these nerves, resultant in a reduced sense of smell. Smoking also alters the shape of taste buds, making them less sensitive. When you quit smoking, the olfactory nerves and taste buds have a chance to heal. You may find that coffee smells stronger and food tastes saltier.
After 1 week
Within a week of abstinence from cigarettes, your respiratory system will begin to repair itself. The nose and respiratory tract are lined with tiny hairs called cilia which filter out dust and debris from the air as you breathe. Smoking damages the cilia, allowing impurities to enter the lungs. If you find yourself coughing more frequently in the first two weeks after you stop smoking, this is a sign that the cilia are regenerating and helping to rid the lungs of toxins.
After 3 months
Three months after you stop smoking, your lung capacity will increase by approximately 30%. The lungs contain tiny air sacs called alveoli which transfer oxygen from inhaled air to the blood. Smoking damages the alveoli, making it more difficult to take in oxygen. This is what causes smokers to experience shortness of breath following moderate physical activity. After you stop smoking, the alveoli begin to heal, allowing you to climb stairs without gasping.
After 1 Year
About a year after your last cigarette, your risk of coronary heart disease falls to half that of active smokers. Smoking is the leading behavioral risk factor for cardiovascular disease, ahead of an unhealthy diet and physical inactivity. Nicotine raises blood pressure, carbon monoxide impedes circulation and another chemical in cigarette smoke, acrolein, affects the way the body processes cholesterol, allowing greater amounts to remain in the blood. Acrolein also decreases the ratio of HDL (the ‘good’ cholesterol) to LDL (the ‘bad ‘cholesterol).
After 3 Years
Approximately three years after you stop smoking, your risk for stroke can fall to that of a lifetime non-smoker. High HDL cholesterol caused by smoking can lead to atherosclerosis, where plaque deposits form on artery walls. Carbon monoxide increases your blood’s tendency to form clots. If a clot forms in a narrowed artery leading to the brain, it can cause a blockage, cutting off the blood supply and causing an ischaemic stroke.
After 5 years
Five years after you give up smoking, the risk for developing cancers of the mouth, throat, and esophagus is cut in half. Tobacco use is estimated to cause more than 90 % of oral cancers in men and 60% of oral cancers in women. Known carcinogens in cigarettes include formaldehyde, arsenic, cadmium, benzene and tar, the brown substance that stains a smoker’s teeth. These agents can cause mutations of cells in the mouth which leads to uncontrolled cell growth and cancer.
After 10 years
Ten years after you stop smoking for good, your risk of dying from lung cancer drops to half that of someone who continues to smoke. Lung cancer accounts for one in four of all cancer deaths and 86% of cases are linked to smoking. Carcinogens in cigarettes are inhaled into the lungs where they damage the DNA of the cells and cause them to become precancerous. If you stop smoking before developing cancer, you stop subjecting these abnormal cells to carcinogens. After ten years, most cells that were precancerous have been replaced with healthy ones.
After 15 – 20 years
Eventually, the body heals itself of the majority of damage caused by smoking. After 15 cigarette-free years, the risk of coronary heart disease is the same for a former smoker as for someone who has never smoked. After 20 years, the risk of death from almost all other natural causes is similar to that of lifetime non-smokers. The risk for lung cancer remains higher and every year spent smoking increases it. Knowing this, it makes sense to stop smoking sooner rather than later.