20 minutes: The nicotine in cigarettes forces your heart to work harder, increasing your heart rate and blood pressure. After just 20 minutes after your last cigarette, both begin to decrease to normal levels. Since smoking narrows blood vessels, it reduces blood flow to the extremities, and many smokers report that they regularly experience cold hands and feet. After the 20-minute-mark, these effects also reduce, and your body returns to its normal temperature.
8 hours: After 8 hours, the level of carbon monoxide and nicotine in your body is reduced by half. Carbon monoxide displaces oxygen in your bloodstream, meaning that the more you smoke, the more your cells are starved of the oxygen they need to function properly. This is most noticeable with things like dizziness or headaches after smoking (the effects of carbon monoxide on the brain) and shortness of breath (the effects of carbon monoxide on the lungs).
12 hours: Only halfway through the first day and your carbon monoxide levels are already back to those of a non-smoker, meaning your oxygen levels are back to normal too! A massive achievement!
24 hours: Your risk of having a heart attack has already reduced, and your lungs are beginning to clear themselves of mucus. As time passes your risk of other diseases (lung disease, chronic obstructive pulmonary disease, coronary heart disease and cardiovascular disease)
48 hours: After two days, you’ve managed to rid nicotine from your body. Your sense of smell and taste will gradually begin to return as your nerve endings start repairing. Treat yourself to something tasty!
72 hours: Your bronchiole tubes in your lungs begin to relax, making breathing a whole lot easier. Your lungs also become much better at filling with air. What’s more, you’ll find that your energy levels begin to increase too. You’ll probably find that physical activity isn’t so much of a struggle anymore as your lung function improves.
1 week: You’re over the worst of your nicotine withdrawal symptoms, and your body has already done a great deal of repair. Now it’s all about utilizing quit smoking therapies to make sure you remain smoke-free. If you’ve successfully managed a week without cigarettes, you can manage a lifetime! Congratulations!