A growing body of research suggests that heart attacks, angina, and other heart conditions increase in winter and summer.
Recent research may explain why.
Researchers looked at an international registry of 1,113 people with acute coronary syndrome, the majority of whom were Japanese. A heart attack is a type of acute coronary syndrome that occurs when the blood supply to the heart muscle is suddenly reduced or cut off.
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The researchers used images of fatty deposits in participants’ coronary arteries to categorize people into groups with plaque rupture, plaque erosion, and calcified plaque. Each plaque scenario can block blood flow and cause a heart attack or other cardiac event. However, rupture is more immediate and occurs when the calcified plaque breaks down. Erosion can occur over time.
“We looked at these three underlying mechanisms to see if they differed by season. As expected, we found significant differences,” said the study, published in the Journal of the American Heart Association. said lead author Dr. Ik-Kyung Jang.
Dr. Jang is an interventional cardiologist and director of the Integrative Physiology and Imaging Cardiology Laboratory at Massachusetts General Hospital in Boston.
Seasonal differences
In those with plaque rupture, the prevalence of hypertension was also higher in winter. However, people with plaque erosion or calcified plaque were not more likely to have high blood pressure.
One reason why ruptures increase in the winter is that cold temperatures cause blood vessels to constrict and narrow, and high blood pressure can trigger plaque rupture, Dr. Zhang said.
Another potential culprit? “Infections, especially influenza, can cause systemic inflammation, and plaque rupture is also associated with inflammation, so that may also contribute to the higher incidence of acute coronary syndromes in winter.” he said.
Meanwhile, plaque erosion increased in summer. According to Dr. Chan, it’s easy to become dehydrated during hot weather, which causes your blood to thicken. This puts stress on the endothelium, the thin layer of cells lining blood vessels, which can cause erosion.
Dehydration symptoms, effects of stress
Dr. Tom Stith, a cardiologist at Sanford Health, sees many heart problems commonly associated with summer and winter weather.
“Hot weather and dehydration can have a very negative impact on heart health,” Dr. Stith told Sanford Health News. “Stay hydrated and be aware that summer weather can make you more prone to heart problems, including heart attacks. Along with staying hydrated, eat a heart-healthy diet. Please be careful.”
Dr. Stith said illness can also put stress on the heart.
Other lifestyle factors
Dr. Robert Kroner, chief scientific officer and scientific director of the Heart and Vascular Institute at the Huntington Medical Institute in Pasadena, California, said the increase in winter cardiac events holds true even in warmer climates. He was not involved in the recent research.
However, in an earlier study, Dr. Kroner and his colleagues analyzed deaths from coronary heart disease in Los Angeles County between 1985 and 1996. They reported that mortality rates were highest in December and January and lowest in summer and early fall.
“This applies not only to climates known to be cold, such as the northeastern United States, but also to more moderate climates,” Dr. Kroner said. “People get used to the weather, but if it gets even a little bit colder, that alone can increase cardiac events.”
Related: Heart attack signs and risks
Dr. Kroner said lifestyle factors may also explain the increase in plaque rupture in the winter, although more research is needed.
For example, during the winter holidays, people tend to eat salty foods that make them fat and drink too much alcohol, which increases the risk of heart disease. Additionally, smoke from fireplaces can further worsen indoor air pollution and cause cardiovascular events.
Shoveling snow can also increase the strain on your heart.
“There are studies showing an association between snow shoveling and snowstorms and an increase in cardiac events,” Dr. Kroner said.
What you can do
Dr. Chan suggested that doctors educate high-risk patients (those who are elderly or have risk factors such as diabetes, obesity, high blood pressure, or high cholesterol) about the risks of cold weather and how to protect themselves.
“If people take steps to stay warm in the winter and stay hydrated in the summer, we can expect to see fewer cases of acute coronary syndrome throughout the year,” said Dr. Chan.
Dr. Stith said if you have signs or symptoms of heart disease, the first step to seek treatment is to call your doctor’s office or 911.
“As we already know, and this evidence-based study shows, having a heart-healthy lifestyle saves lives,” he said.
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Categories: Family Medicine, Heart, Specialty Care
