THE HOUR AFTER SMOKING POT

Harvard researchers reported yesterday that the risk of a heart attack is
five times higher than usual in the hour after smoking a marijuana
cigarette. Murray Mittleman of the Harvard School of Public Health and
Boston's Beth Israel Deaconess Medical Center and colleagues questioned
3,882 male and female heart attack victims at 62 locations across the
country about their habits and found that 124 were marijuana users.

While marijuana use was uncommon among the elderly heart patients, 13
percent of those under age 50 said they smoke it, Mittleman reported at a
conference in San Diego of the American Heart Association. Among those
questioned, 37 had their heart attacks within a day of using marijuana,
including nine within an hour afterward. The researchers calculated that
someone's risk of a heart attack is five times higher during the hour after
using marijuana.

After an hour, the risk falls to twice normal.

It soon returns to the usual level.

Whether a fivefold increase is a worry depends on whether someone has other
risk factors, such as high blood pressure or diabetes.

The increased risk is probably insignificant for a 20-year-old, whose
chance of a heart attack is vanishingly small.

In any case, the risk of a heart attack from any single session of
marijuana smoking is likely to be low. Mittleman said that for an otherwise
healthy 50-year-old man, it is about 10 in 1 million.

Until now, marijuana has not been much of an issue in heart disease, since
older folks do not typically smoke pot. However, this could change as baby
boomers take their pot-smoking habits into middle age and beyond. Marijuana
typically makes the heart speed up by about 40 beats a minute.

It is unclear whether this contributes to heart attacks.