Dangerous number of coffees per day revealed

The exact number of coffees that is safe to drink per day has been revealed by scientists.

Too much coffee can be a latte for the heart to handle, with a new study linking over 400 milligrams of caffeine a day to an increased risk of cardiovascular disease even for otherwise healthy people.

“Regular caffeine consumption could disturb the parasympathetic system, leading to elevated blood pressure and heart rates,” explained lead study author Nency Kagathara, of Zydus Medical College and Hospital in Dahod, India.

Kagathara’s team measured the blood pressure and heart rates of 92 healthy adults after they performed a three-minute step test. Participants were 18 to 45 years old with normal blood pressure at the start of the experiments, the New York Post reports.

Nearly 20 per cent of participants consumed more than 400 mg of caffeine every day, which is the equivalent of about four cups of coffee, 10 cans of soda or two energy drinks.

For reference: there’s 75mg of caffeine in a 100ml long black, there’s 87mg of caffeine in a 100ml flat white, a 100ml cappuccino contains 101.9mg of caffeine and a short black espresso contains 107mg of caffeine.

Chronic daily consumption of 400 mg was found to raise heart rate and blood pressure over time. The study findings were presented on Thursday at the American College of Cardiology conference in Delhi, India.

Too much coffee can be too much for the heart to handle. Picture: Getty

The US Food and Drug Administration has said that 400 mg of caffeine a day is “not generally associated with dangerous, negative effects,” while acknowledging that some people are more sensitive to caffeine and it can be metabolised at different rates.

The Mayo Clinic says up to 400 mg of caffeine “appears to be safe for most healthy adults.”

Caffeine is a stimulant that can promote the production of the stress hormones noradrenaline and epinephrine, increasing heart rate and raising blood pressure by narrowing blood vessels.

But it’s also been found to elevate mood and possibly lower the risk of certain cancers, among other benefits.

Kagathara reported that urban women in business and management roles had the highest daily caffeine intake in her study.

Those who consumed more than 600 mg of caffeine a day had significantly elevated heart rates and blood pressure after five minutes of rest following the step test.

“Due to its effect on the autonomic nervous system, regular caffeine consumption could put otherwise healthy individuals at risk of hypertension and other cardiovascular events,” Kagathara said.

“Increasing awareness of these risks is vital to improve heart health for all.”

This article appeared in the New York Post and was republished with permission.

Originally published as Dangerous number of coffees per day revealed