Researchers say a 31-year-old woman’s case shows that doctors should ask about soda consumption during medical screenings.

A Monaco woman who drank nothing but soda for 16 years developed heart problems and a fainting disorder by age 31, according to the European Society of Cardiology.

Researchers say that kind of excessive soda consumption may have caused to woman to suffer from a potassium deficiency and a life-threatening arrhythmia, or irregular heartbeat.

Dr. Naima Zarqane and Prof. Nadir Saoudi from the Princess Grace Hospital Centre in Monaco say a 31-year-old woman was admitted to the hospital for a traumatic form of fainting.

After excluding other possible causes—including a family history of heart problems, digestive symptoms, and possible hormonal abnormalities—blood tests showed the woman had low levels of potassium and abnormally high heart muscle sensitivity, which can lead to a host of problems.

Doctors found the likely cause when they took her medical history—the woman had replaced her water intake with 2 liters of soda a day. After being instructed to stop drinking soda for one week, the woman’s potassium levels returned to healthy levels and her heart muscle sensitivity ceased.