Here’s what the amount of coffee you drink could be doing to your body.

First up, what’s your coffee order?

Baristas reckon they can tell a lot about their customers by their coffee order. They say cappuccino drinkers are sociable and optimistic, artisanal brew lovers are so hip it hurts, and short black enthusiasts apparently tend to be high-energy and a bit… intense.

So if your favourite coffee says a lot about your personality, what can the amount of coffee you throw back in a typical day tell you?

Long-term effects of coffee:

Where coffee is concerned, one might assume less is better — after all, espresso addicts tend to admit to their habit rather sheepishly. However, there is some research to suggest more than a couple of coffees a day isn’t totally catastrophic for your health. (Hoorah!)

what coffee does to your body
The amount of coffee you throw back in a typical day says a lot about your health. Image via iStock.

Three to six cups of coffee per day:

“If you’re drinking between four to six cups of coffee a day, over a long period of time… it appears to lower your probability of dying overall,” Dr Ian Musgrave, senior lecturer in the University of Adelaide’s pharmacology department, told The Glow.

“It appears to lower your probability of [type 2] diabetes, it appears to lower your probability of cardiovascular disorders, it may lower your probability of getting Parkinson’s disease.”

Three to five cups of coffee per day:

A study of young Korean adults published this year found that when compared to subjects who drank no coffee, those who consumed three to five cups per day had 40 per cent less calcium deposits in their coronary arteries (which can be a sign of developing heart disease).

As if that’s not enough to alleviate your concerns, The Conversation reports a review of 20 studies showed those subjects who drank the most coffee had a 14 per cent lower risk of dying prematurely from any cause, compared to those who drank the least. Even one or two cups a day reaped some benefit.

Despite these benefits, research suggests no country in the world drinks more than three cups of coffee on the average day. The Netherlands comes in closest, with 2.4 cups per day per capita. (Post continues after gallery…)


That said, high coffee intake — in many studies, this term applies to 300-500mg of caffeine, i.e. around five or six cups of strong coffee — can affect individuals detrimentally in some respects. According to Professor Chris Semsarian, a cardiologist from Sydney’s Royal Prince Alfred Hospital, exceeding the recommended daily caffeine intake levels — 400mg for adults, 100mg for adolescents and children — can have “significant” cardiac and neurological symptoms.

“[These include] palpitations, fast heart rates, high blood pressure and insomnia … Chronic use of caffeine can lead to irritable behaviour, higher blood pressure and things like that,” he told The Glow.

One to three coffees per day:

There are also health benefits associated with low coffee intake.

For instance, in the aforementioned study regarding coffee’s effects on coronary artery calcium deposits, the benefits weren’t limited to those who drank more than three cups. Those who drank between one and three coffees a day had 35 per cent less calcium deposits than non-coffee drinkers — a better outcomes than subjects who drank more than five coffees. This group had just 19 per cent less deposits than those who abstained completely.

Another study published this year found strong evidence that consuming even one coffee per day could go some way in offsetting the health impacts of alcohol and decreasing the risk of liver cancer. Research from 2006 also found for each cup of coffee subjects consumed a day, they were less likely to develop alcohol cirrhosis, a liver disease.

Short-term effects of coffee:

When it comes to the immediate effects of coffee, it’s hard to say exactly what one or two or even five coffees will do to your body because the substance doesn’t have a uniform affect across the population. Absorption and metabolism rates, physical build and individual tolerance to caffeine can vary dramatically from one person to the next.

what coffee does to your body
“When it comes to the immediate effects of coffee, it’s hard to say exactly what one or two or even five coffees will do…” Image via iStock.

“What I’ve seen in clients is that coffee does affect people very, very differently. Some people, I’ve found, can do really well on two or three coffees a day; other people manage to get jittery after one coffee and are best to avoid it,” says nutritionist and dietician Arabella Forge.

The type of coffee roast and how it’s consumed — with or without milk, sugar, and other additives — also influences its effects. “One cup of instant coffee is around 60-100mg of caffeine. If you’re having a lot of additives and preservatives or having it with milk, the caffeine level will actually be less,” Forge explains.

Within one hour of drinking your coffee:

According to The Conversation, coffee peaks in the bloodstream within an hour of consumption; although 2008 research from the University of Barcelona suggests its stimulating effects can become present in as little as 10 minutes. Forge says the substance’s half-life is around five to six hours, meaning half of it has been metabolised in that time. (Post continues after gallery.)

However, in some people the effects can last a lot longer. Research has shown that in caffeine-sensitive people, just one cup of coffee in the day (even the morning!) can be detrimental to their sleep that night. Unlucky.

Generally speaking, Forge says you can expect to notice coffee’s stimulant effects and changes to your feelings of alertness. In higher doses, she says, this can lead to jittery or anxious sensations. Other short-term caffeine effects include the opening of the breathing tubes and constriction of blood vessels on the skin. Then there’s the whole ‘coffee runs’ issue. (Post continues after gallery…)

Dr Ian Musgrave previously told The Glow people who aren’t used to coffee can experience “very exaggerated” side effects if they suddenly drink a lot of it at once. “You may even show signs of caffeine intoxication where you get the tremors, the heart palpitations,” he said.

Ultimately, your coffee intake should be judged and adjusted according to your body’s response to it. “Choose good quality coffee, be wary of what you’re adding to it, and listen to how your body feels… The way I would gauge it is that if you’re feeling jittery, or its interfering with your sleep patterns or your ability to relax, then you’re probably having too much,” Forge says.

Ultimately, moderate coffee consumption isn’t something you should be worrying about. If you take it too far, your body — and your sleep patterns — will probably give you a big hint.

A version of this post was originally published on The Glow. 

How many coffees do you drink per day? What’s your limit?

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