As baby boomers reach the age at which heart disease is the leading cause of sickness and death, “we may see an increase in marijuana-associated heart attacks,” says Murray Mittleman, an assistant professor at Harvard Medical School and Harvard School of Public Health. The danger exists in the first hour after smoking pot, Mittleman told an American Heart Association meeting in 2000. “It causes the heart rate to increase by about 40 beats a minute,” he says. “Blood pressure increases then abruptly falls when the person stands up. This could precipitate a heart attack.” As an immediate trigger for heart attack, pot smoking is nearly twice as dangerous as sex for a sedentary person, exercise for a fit male or female, a tantrum of rage, or a bout of anxiety. But it’s less risky than a spurt of exercise for a couch potato or a snort of cocaine.