A new study suggests that heart attacks often occur when temperatures drop.
According to a report published in the Journal of the American Heart Association, based on medical data and weather information, over a period of more than 15 years, the researchers linked the increased exposure to heart attacks and low temperature, air pressure and increase wind speed and decrease the periods of sunshine.
"All the heart attacks in an entire country have been followed for 16 years, as well as weather data on the day of the heart attack," he said.
"We have data on more than 280,000 heart attacks and three million meteorological data," Dr. David Erling, head of cardiology at Lund University and Sweden's Scona Hospital in Sweden, told Reuters Health.
Irling and his colleagues examined Swedish heart records, which record all patients who had heart attack-like symptoms and were transferred to intensive care units or coronary catheterization laboratories. The records include health information about patients, including age and body mass, whether or not smoking, results of ECG, types of surgical interventions, drugs and diagnosis.
For weather information, the researchers used the Swedish Meteorological Institute, which records data from 132 air stations across the country.
Irling and his colleagues analyzed weather and weather data from 1998 to 2013 for 274,000 and 29 patients, half of whom were 71 or older.
While lower atmospheric temperature, atmospheric pressure, increased wind speed and reduced sun brightness were all associated with a statistically significant increase in the risk of a heart attack, the most obvious effect was associated with temperature.
The researchers found an increase in heart attack in days of less than freezing. The incidence rate dropped when temperatures rose by three or four degrees Celsius.
But why could the cold weather raise the risk of a heart attack?
"Cold temperatures increase the narrowing of arteries and veins ... and with someone who has a 70 to 80 percent blockage in the arteries, which may not cause any symptoms, the arteries may narrow," said Dr. Nisha Galani of the Interventional Vascular Center in New York. Enough to stop the flow of blood to the required degree. "
Cold may also increase the risk of blood clotting, she said.
Other factors linked to winter may increase the risk of heart attacks, such as removing snow that raises blood pressure, Galani said. She said caffeine had a similar effect on arteries, though much less.
"So the worst thing you can do is go out in under-zero temperatures, then remove the snow and then have coffee to feel warm.
