Smoking releases thousands of chemicals into your body. The result isn’t only damage to your lungs, but also your heart and many other body structures.

But even if you’ve smoked for many years, you can reverse these effects and experience health benefits from the first hours you stop smoking to the decades after you quit.

Below are some of the many health milestones you can experience by quitting smoking today.

The positive health effects of quitting smoking begin 20 minutes after your last cigarette. Your blood pressure and pulse will start to return to more normal levels.

In addition, fibers in the bronchial tubes that previously didn’t move well due to constant exposure to smoke will start to move again. This is beneficial for the lungs: These fibers help move irritants and bacteria out of the lungs, helping reduce the risk for infection.

Within eight hours, your carbon monoxide levels will return to a more normal level. Carbon monoxide is a chemical present in cigarette smoke that replaces oxygen particles in the blood, lowering the amount of oxygen your tissues receive.

When carbon monoxide goes away, your oxygen levels start to increase to more normal levels. This increased oxygen helps nourish tissues and blood vessels that were getting less oxygen while you were smoking.

By the one-day mark, you’ve already decreased your risk of heart attack. This is because of reduced constriction of veins and arteries as well as increased oxygen levels that go to the heart to boost its functioning.

Nicotine levels in your bloodstream have also decreased to negligible amounts at this time.

At 48 hours, previously damaged nerve endings start to regrow. You may also start to notice that senses that were previously dulled due to smoking improve. You may realize you’re smelling and tasting things better than you were before.

Within three days after quitting smoking, you’ll often find yourself breathing more easily. This is because the bronchial tubes inside the lungs have started to relax and open up more. This makes air exchange between carbon dioxide and oxygen easier.

In addition, your lung capacity, or ability of the lungs to fill up with air, increases about three days after quitting.

The one-week milestone is important not only for your health, but for your success rate in quitting smoking successfully long term. Smokers who successfully make it one week without smoking are nine times as likely to successfully quit.

The chances of quitting smoking for good increase with every attempt. If you can make it to one week, you can make it for a lifetime.

Within two weeks of quitting smoking, you may start to notice you’re not only breathing easier. You’re also walking easier. This is thanks to improved circulation and oxygenation.

Your lung function also increases as much as 30 percent about two weeks after stopping smoking, notes the University of Michigan.

In just one short month, you can experience many health changes related to stopping smoking. One is feeling a sense of heightened overall energy.

You may also notice that many smoking-related symptoms have decreased, such as sinus congestion and shortness of breath with exercise.

In addition to these benefits, fibers in the lungs that help keep the lungs healthy are growing back. These fibers can help reduce excess mucus buildup and protect against bacterial infections.

Within three months after quitting, a woman can improve her fertility as well as reduce the risk that her baby will be born prematurely.

After six months of quitting, many people often notice they’re better able to handle stressful events that come their way without feeling like they need to smoke.

They may also notice they’re coughing up much less mucus and phlegm. This is because the airways are much less inflamed without the constant exposure to cigarette smoke and the chemicals contained within cigarettes.

After one year of quitting smoking, your lungs will have experienced dramatic health improvements in terms of capacity and functioning. You’ll notice how much easier you breathe when you’re exerting yourself and how much less coughing you have compared to when you smoked.

In addition to these health benefits, you’ll have saved a dramatic amount of money. Smoking cigarettes is expensive. If you smoked a pack of cigarettes per day, you’ll have saved thousands of dollars at the one-year mark.

In three years after quitting smoking, your risk of a heart attack has decreased to that of a nonsmoker.

Smoking not only limits oxygen flow to the heart. It also damages the lining of the arteries. Fatty tissue starts to build up, making it more likely that a person will experience a heart attack or stroke. Quitting smoking can help reverse these effects and promote a healthier heart in the years to come.

Five years after you stop smoking, your risk of death from lung cancer has dropped by half compared to when you smoked, according to the University of North Carolina.

At the 15-year mark, your risk for heart attack and stroke has decreased to equal that of a person who’s never smoked before. While it can take time to turn back the clock on the effects of smoking, having 15 smoke-free years represents a major milestone for your health and overall well-being.

With so many health benefits of quitting smoking, the time to quit is now. You can start by making a plan using resources from the Centers for Disease Control and Prevention and talking to a smoking cessation counselor by calling 1-800-QUIT-NOW.

You can enlist your doctor, family, and friends to support you in your quest to live a healthier, smoke-free lifestyle. Be sure to celebrate each time milestone along the way — you’re worth it.