Swedish researchers looked at 20 years of records and discovered that the number of heart attacks dipped on the Monday after clocks were set back an hour, possibly because people got an extra hour of sleep.
And moving clocks forward in the spring appeared to have the opposite effect. There were more heart attacks during the week after the start of daylight saving time, particularly on the first three days of the week.
"Sleep affects our cardiovascular health," said Dr. Lori Mosca, director of preventive cardiology at New York-Presbyterian Hospital, who was not involved in the research. The findings show that "sleep not only impacts how we feel, but it may also affect whether we develop heart disease or not."
The study was described in a letter published in today's New England Journal of Medicine by Dr. Imre Janszky of the Karolinska Institute and Dr. Rickard Ljung of Sweden's National Board of Health and Welfare.
Janszky said he came up with the idea for the study after last spring's time change, when he was having problems adjusting.
Overall, in the week after "spring forward," there was a 5 percent increase in heart attacks. In the week after "fall back," the number of heart attacks was about the same, except on Monday, which had a 5 percent decrease.
"The finding that the possibility of additional sleep seems to be protective on the first workday after the autumn shift is intriguing," the authors wrote.
Good for the ticker
Standard time returns this weekend, so set your clocks back an hour Saturday night. Most Americans will get an extra hour of sleep, but it also means some will forget to change their clocks and show up an hour early for church or other events on Sunday.
Proportions not biblical, but close
The 2004 tsunami that killed 230,000 people in 14 countries was the biggest in the Indian Ocean in some 600 years, two new geological studies suggest. That long gap might explain how enough geological stress built up to power the huge undersea earthquake that launched the killer waves. The work appears in today's issue of the journal Nature. By digging pits and taking core samples in Thailand and northern Sumatra, research teams found evidence that the last comparably large tsunami struck between 1300 and 1400.
New book by Marx takes opposing view
Coming soon to German bookstores: a new Das Kapital from another Marx. But the author says it is not a defense of communism. Munich's Archbishop Reinhard Marx says his work is to some extent "an argument with Marxism." Marx wrote the first chapter of his Das Kapital: A Plea for Humanity as a letter to his "dear namesake" - Karl Marx. The archbishop writes that "the consequences of your thinking were in the end disastrous."
Ghana wants tribal leader's head back
The decapitated head of African tribal chief Badu Bonsu II has been sitting in a Dutch university since the 19th century, and Ghana wants it back. Officials at Leiden University Medical Center said they will consider returning it if a formal request is made. Bonsu was killed in retaliation for the deaths of two Dutch emissaries, whose heads were hung from Bonsu's throne as trophies.