If you’ve just scheduled surgery for anything from a herniated disk to a knee replacement and you’re a smoker, now is the time to stop.

"Everyone knows that smoking is bad for you, but it’s even worse for people who are about to have surgery because it can increase the risk of complications and slow healing after surgery," said Geisinger general surgeon Ryan Rusnok, D.O.

Smokers who have surgery are also at a higher risk of death in the days and weeks following, compared to nonsmokers.

One risk is blood clots. Patients recovering from surgery are already at higher risk of having a blood clot following a procedure. Smoking further increases the risk of blood clots that can form in the legs and travel to the lungs. When a blood clot travels to the lungs, it’s called a pulmonary embolism, and it can be deadly.

During and after surgery, smokers are also at an increased risk for heart problems. Smoking damages your heart, which means that it has to work harder to keep blood pumping through your body during surgery.

Even if your surgery goes smoothly, smoking puts you at an increased risk for heart problems like stroke and a heart attack after surgery.

After you begin the healing process at home, smoking can also draw out the healing process.

"Smoking deprives your body of oxygen, which your wounds need to heal properly," said Dr. Rusnok. This prevents tissue from quickly repairing itself.

It can also increase the risk of the wound becoming infected after surgery.

But people who stop smoking—even longtime smokers who quit just a few weeks before surgery—may see fewer complications and a lower risk of these problems associated with smoking.

"The sooner you quit smoking before surgery, the better," said Dr. Rusnok. "Four weeks before surgery is recommended, but if you can do it before that, you can decrease the risk even more."

Even if you’ve tried quitting in the past, it’s important to try to quit smoking again.

Before you stop smoking, stock up on gum, hard candy and even carrot sticks as an oral substitute. Remove all of the cigarettes, lighters and ashtrays from your house, apartment, office and car.

You should also seek support.

"Reach out to friends and family members when you stop smoking so they can help hold you accountable," said Dr. Rusnok. Smoking cessation and support groups can help you deal with withdrawal symptoms and connect you with other people who have stopped smoking.

Your doctor can also help you get support and recommend oral substitutes such as nicotine replacement therapy or other medicines that can make quitting easier.

Making changes to your daily routine can also help.

"If you tend to smoke when you wake up, try going for a walk or run instead," said Dr. Rusnok.

Quitting smoking will not only reduce the likelihood of complications and risks during and after your surgery, it will also add years to your life.