Cold snaps and air pollution can trigger heart failure, and breathing dirty air day in and day out may help heart disease develop in the first place, several studies have shown.
Stress is probably causing the effects in both cases, four teams of researchers told a meeting of the American Heart Association in New Orleans yesterday.
Dr Gad Cotter of Duke University in North Carolina studied 300 patients last winter in Israel. When the temperature dropped below about 7 degrees - a cold snap for Israel - between two and three times the usual number of people were taken to hospital with acute heart failure than on warmer days."During days when there was high pollution we also had more patients with acute heart failure," he said.