There’s new evidence shingles may come with health consequences beyond an agonizingly painful rash: It could mess with your heart health too. People who developed herpes zoster, or shingles, had an almost 60% higher risk of heart attack and a 35% higher risk of stroke than those who avoided the resurgence of chicken pox, warns a research letter published in the Journal of the American College of Cardiology this week.

The risks were highest in the first year after experiencing shingles, and the threat of stroke was highest in people under 40, the researchers wrote. Exactly why shingles would impact your heart isn’t clear, but it’s not a direct link, said Dr. Mary Norine Walsh, president of the American College of Cardiology. “Having herpes zoster is a sign of a slight decrease in your immune system and that alone may be responsible for the higher stroke rates.”

For the study, the researchers analyzed a national database of more than 500,000 people who had undergone a medical check-up in South Korea. More than 23,000 of them were diagnosed with shingles. Compared to shingle-free people, they were more likely to be female and have high blood pressure, diabetes and high cholesterol, but they also smoked and drank alcohol less and exercised more, the authors noted. Shingles raised their overall risk of having a cardiovascular event by 41%. Previous studies have also found the shingles-heart health link.

About one out of three Americans will develop shingles, which is caused by the same virus that triggers chickenpox. Although anyone who’s had chickenpox is at risk for shingles at any point in their life, about half of all cases involve people 60 or older, according to the Centers for Disease Control and Prevention.

The main symptom is a painful rash that develops on one side of the face or body, with blisters that scab over in about a week. The only way to reduce the risk is to get vaccinated, so the CDC recommends people 60 and older get the shingles vaccine regardless of whether or not they recall having had chickenpox.

The new study could offer more motivation to get the shot. To prevent chickenpox in the first place, the CDC recommends two doses of vaccine for children, teens and adults.

The basic advice to lower your heart attack and stroke risk remains the same: Don’t smoke, exercise 30 minutes most days and know what your cholesterol level is. Maintain a normal body weight, be screened for diabetes and have it under control; know your blood pressure and if it’s high and talk to your doctor about treatment.