As temperatures drop, the risk of heart attacks may go up for the sick and elderly, London’s Daily Mail reported.

A new study found that a drop in temperature of 1 degree Celsius increases the risk of heart attack by two percent for the next 28 days. But the greatest risk is in the two weeks after the drop and threatens the elderly and heart disease patients the most.

“This translates to around 200 extra heart attacks, so if there are successive falls over a number of days there would be additional sets of extra heart attacks,” said Krishnan Bhaskaran, a researcher with the London School of Hygiene and Tropical Medicine.

Researchers from the London School of Hygiene and Tropical Medicine analyzed 84,000 hospital admissions for heart attacks between 2003 and 2006, and compared them to the daily temperature of 15 geographical locations in England and Wales, where the patients were admitted.

The researchers found that hotter weather didn’t result in a higher risk of heart attack, but noted that Britain’s mild climate, which rarely gets very hot, may be the reason.

Those who had used aspirin over a long period of time had a lower risk of heart attack.

Click here to read more from the Daily Mail.