Downing just one-and-a-half large cans of energy drink is enough to narrow your blood vessels, scientists say.

Drinks filled with sugar and caffeine block vessels, which can then lead to a stroke or heart attack if the products are consumed regularly.

According to a new study, young, healthy men and women experienced notably diminished function soon after consuming a single regular 24 US oz can – equivalent to nearly three 250ml cans of Red Bull cans or one-and-a-half 500ml cans of Monster Energy.

Drinks filled with sugar and caffeine block vessels, scientists say, which can then lead to a stroke or heart attack if the products are consumed regularly (Picture: PA)

The study is the first to shed light on the possible mechanism linking high consumption of energy drinks to an increased risk metabolic syndrome.


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This is a group of disorders such as diabetes, high blood pressure and obesity that trigger cardiovascular disease and other conditions affecting blood vessels.



The finding presented at an American Heart Association conference in Chicago was based on 44 non-smoking medical students in their 20s.

Flexibility of their blood vessels was measured using a technique called artery flow-mediated dilation (FMD).

Beforehand vessel dilation was on average 5.1 per cent in diameter.

What happens when you drink energy drinks regularly? Vessels become less flexible as the cells that line them respond to food and drink derived fats and sugars circulating in the blood. This makes them more susceptible to the build-up of cholesterol that can lead to heart disease. Short term changes are normal and usually last for several hours. But if we repeatedly have unhealthy foods or drinks it can lead to cardiovascular diseases. FMD is an ultrasound measurement. The researchers believe caffeine, taurine, sugar and herbal ingredients in energy drinks are bad for the endothelium – the lining of the blood vessels. Caffeine can cause the walls of blood vessels to contract – leading to a narrowing of them. It also releases extra stress hormones – such as adrenaline – which can temporarily increase blood pressure.

But 90 minutes after downing the unnamed energy drink this fell to 2.8 per cent.

Dr John Higgins, of Texas University in Houston, said that this suggested ‘acute impairment in vascular function.’

Energy drinks have been associated with many health problems associated with the heart, nerves and stomach.

Some experts believe the cardiovascular side effects could be related to their impact on blood vessel – or endothelial – function.

So Dr Higgins and colleagues tested this before and after the participants consumed the drink.

Energy drinks have been associated with many health problems associated with the heart, nerves and stomach (Picture: DPA/PA Images)

Dr Higgins said: ‘As energy drinks are becoming more and more popular, it is important to study the effects of these drinks on those who frequently drink them and better determine what, if any, is a safe consumption pattern.’

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Earlier this year it was revealed nearly 70 per cent of 10 to 17 year-olds in the UK consume energy drinks – more than anywhere else in Europe.

The drinks, which have been linked to headaches, abdominal pain and insomnia, can contain 160mg of caffeine, despite 105mg being the safe daily limit for 11 year olds.

Sales of the energy drinks in the UK increased by 185 per cent between 2006 and 2015, making the market worth more than £2 billion.

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