Experts at the Baker Heart and Diabetes Institute in Melbourne examined a series of studies looking at the effects of caffeine on conditions such as arrhythmias (aka, when the heart beats too fast, too slow or unevenly.)
Their findings? It minimises the effects of adensosine, which is the chemical that increases the risk of these abnormal rhythms.
“There is a public perception, often based on anecdotal experience, that caffeine is a common trigger for heart rhythm problems,” explained the lead researcher, Dr Peter Kistler.
“Our extensive review of the medical literature suggests this is not the case.”
In one study involving more than 200,000 people, the risk of atrial fibrillation - when the heart beats at an irregular rate – dropped by six per cent in regular coffee drinkers. Another involving 115,993 participants found a 13 per cent reduction, while in a third, the heart rate of 103 heart attack patients significantly improved after increasing their caffeine intake.
From this, the experts concluded that 300 milligrams or the equivalent of three cups of coffee a day, is safe for patients with heart conditions (pending their doctor’s approval, of course.)
“Caffeinated beverages such as coffee and tea may have long-term anti-arrhythmic properties mediated by antioxidant effects and antagonism of adenosine,” Kistler added. “In numerous population-based studies, patients who regularly consume coffee and tea at moderate levels have a lower lifetime risk of developing heart rhythm problems and possibly improved survival.”