A study presented at the Asian Conference of the American College of Cardiology (ACC) showed that long-term daily intake of 400 milligrams of caffeine (equivalent to 4 cups of coffee) significantly affects the autonomic nervous system, increasing heart rate and blood pressure over time. Research has found that people who consume more than 600 milligrams of caffeine per day still experience significant increases in heart rate (over 100 beats per minute) and blood pressure (over 140/90 mmHg) after a 5-minute break following a 3-minute step test. Researchers suggest that due to the impact of caffeine on the autonomic nervous system, frequent heavy coffee consumption may put otherwise healthy individuals at risk of hypertension and other cardiovascular diseases. Numerous previous studies have shown that an increase in heart rate can increase the risk of metabolic syndrome, heart failure, kidney disease, pulmonary heart disease, dementia, suicide, and other conditions. The study also found that women, business professionals, and managers drink coffee the most. Long term caffeine intake is defined as consuming any caffeinated beverage 5 days a week for a period of more than a year. 19.6% of participants reported daily caffeine intake exceeding 400 milligrams. (New Society)