For patients with cancer of the left breast, radiation therapy can be a cure that kills because it exposes a woman’s healthy heart and lungs to unnecessary radiation—which increases a woman’s risk of ischemic heart disease (blockage of heart vessels that ultimately result in heart attack). But good news! Researchers have found an ingenious solution that is remarkably simple. It’s based on something you naturally do every day—breathe.

But this heart-saving technique is not just any kind of breathing.

The technique involves holding your breath. By filling your lungs and holding your breath during radiation therapy, your lungs, heart and other organs are pushed out of the way of the radiation beam.

Patients using this technique aren’t expected to hold their breaths perfectly during radiotherapy. A machine called the Active Breathing Coordinator (ABC for short) helps them. The patient breathes through a mouthpiece connected to the ABC device, which monitors lung volume. When lung volume is just right and has pushed the heart and other organs out of the way of the radiation beam, the technician operating the machine closes a valve on its mouth piece to create a breath hold and instructs the patient to stay right there. The breath is held for about 20 seconds.

Also, instead of radiation being given all at once, it is given in pulses in lower doses than usual to also reduce the amount of radiation that might hit the heart, lungs or other organs. The pulses are coordinated with the breath holds.

Previous research has shown that this breathing technique does help protect the heart and lungs from radiation, but no one could say exactly how well it did so and especially whether lower doses of radiation were effective at efficiently beating the breast cancer until a research team from Thomas Jefferson University Department of Radiation Oncology in Philadelphia put it to the test.

They recruited 81 women with cancer of the left breast who had more than five cubic centimeters of their hearts located where a radiotherapy beam needed to be directed. Radiation was shot into breast tissue in pulses while patients held their breaths with the aid of the ABC machine. When measuring results, researchers accounted for age, tumor stage and conditions that contribute to heart disease such as high cholesterol and high blood pressure.

And the results were stellar. After an eight-year follow-up period in which patients received regular health checkups, the survival rate was 96%. Not only were the patients’ hearts kept safer and healthier in the aftermath of breast cancer radiotherapy, but 88% of the patients got the same cancer-fighting benefit with the lower doses of pulsed radiation as they would have gotten with the regular dose.

Not everyone will feel comfortable with the machine or qualify for it. You have to be able to hold your breath for up to 20 seconds, and it’s only for patients whose hearts are “in the line of fire” of a radiotherapy beam. But if you’re receiving radiotherapy for cancer of the left breast, it makes sense to ask your doctor if ABC is right for you and can be included in your treatment.