Right amount of coffee reduces heart palpitations by 13%

A cup of coffee with latte art on wooden table
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Drinking coffee can reduce heart palpitations, according to recent research. Three cups a day can lower potentially deadly heart palpitations by up to 13 per cent, reducing the risk of a heart attack or stroke say scientists.

A study of more than 340,000 people found both tea or coffee protect against common heart rhythm disturbances. Healthy antioxidants in caffeine are probably behind the phenomenon, said cardiologist Professor Peter Kistler.

It's commonly assumed coffee can cause the heart to beat faster - potentially causing illness. Lead author Professor Kistler, director of electrophysiology at the Alfred Hospital in Melbourne, said: "There is a public perception - often based on anecdotal experience - that caffeine is a common acute trigger for heart rhythm problems.

"Our extensive review of the medical literature suggests this is not the case."

His team showed caffeine protected against both atrial fibrillation (AF) and ventricular arrythmia (VA). The life-threatening conditions occur in each of the heart's two upper and lower chambers respectively.

Prof Kistler said caffeine blocks a molecule that fuels AF - the most common heart beat problem that can progress to heart failure. It affects about 1.4 million adults in the UK. It causes the heart to beat irregularly or very fast.

In AF the heart pumps blood less efficiently around the body - potentially leading to a stroke-causing clot. VA's are an erratic, disorganised firing of impulses from the organ's ventricles and are the most common cause of sudden cardiac death.

It caused England cricketer James Taylor to retire from the game at the age of just 26. Tony Blair was successfully treated for AF while he was prime minister. He blamed his heart problems on too much strong coffee during an EU conference and doctors advised him to cut back.

Now Prof Kistler and colleagues suggest his doctors may have been wrong and coffee may have had nothing to do with it. They said many doctors advise patients with AF or VAs to avoid coffee, tea and other caffeinated beverages.

But their review published in JACC: Clinical Electrophysiology said coffee and tea are safe and can cut the frequency of irregular heartbeats. The researchers found multiple studies investigating the link have consistently shown a decrease in AF with an increase in consumption of caffeine.

Pooling data from 115,993 showed a 13 percent reduction in risk among regular coffee drinkers. A further 'meta-analysis' of 228,465 participants found AF frequency fell by six percent in those with higher intake of caffeine.

Prof Kistler said arrhythmias are abnormal heart rhythms that cause the organ to beat too fast, slow or unevenly. Some may be harmless or even go unnoticed in patients but others can increase risk for sudden heart attack or stroke.

Prof Kistler said a single cup of coffee contains about 95 mg of caffeine and acts as a stimulant to the central nervous system. Once in the body it blocks the effects of adenosine a chemical that can cause AF.

His team also determined caffeine improved the hearts of patients with VAs. Up to 500 mg daily - equivalent to six cups of coffee - did not increase their severity or rate.

In fact the study of 103 patients who had suffered a heart attack found those selected at random to receive an average of 353 mg per day - almost four cups - had better heart rates and no significant disturbances. Only two studies showed an increased risk for VAs - where patients ingested at least 10 cups and nine cups a day, respectively.

Prof Kistler said: "Caffeinated beverages such as coffee and tea may have long term anti-arrhythmic properties mediated by antioxidant effects and antagonism of adenosine. 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."

But the researchers said energy drinks should be avoided by patients with pre-existing heart conditions. One energy drink can contain anywhere from 160-500 mg of concentrated caffeine. Three quarters of patients with pre-existing heart conditions who consumed two or more energy drinks a day reported palpitations within 24 hours.

Both large population studies and randomised control trials suggest caffeine intake of up to 300 mg/day - just over three cups - may be safe for arrhythmic patients. However, there may be individual differences in susceptibility to the effects of caffeine on the factors which trigger arrhythmias - with up to 25 percent of patients reporting coffee as a cause.

These should be advised to abstain. Future research looking at the impact of this on patients with heart disturbances could clarify this issue, said Prof Kistler.