A new study found that, after all, drinking coffee for a long time does not increase the risk of heart disease. The study looked at 128,000 subjects, men and women, for as long as 20 years, and found no link between heart disease and a daily intake of 6 or more cups of coffee. Volunteers were asked to fill out questionnaires about their diet, exercise, other health habits, and to undergo regular physical exams. It was shown that heavy coffee drinkers tend to smoke and drink alcohol more than usually, things which do raise this risk. 30% of men, who drank 6 or more cups of coffee a day, were more likely to smoke cigarettes, drink alcohol and use aspirin, and were less likely to drink tea, exercise or take vitamin supplements. "We can't exclude the association between coffee consumption and the risk of coronary heart disease in small groups of people," said Rob van Dam, a research scientist at the Harvard School of Public Health and co-author of the study. The study does not show that coffee is safe for everyone. In March, a study showed that people with slow metabolism, if they drink more coffee, have a higher risk of cardiovascular disease that those with a fast one. "If you perceive unpleasant symptoms, such as difficulty falling to sleep when consuming caffeinated coffee, that means you drink too much," van Dam said. He also warned pregnant women to limit themselves to 3 cups of coffee a day, because "the child is very sensitive to caffeine."