The incarnations of coffee during the Corona period (Avi Rosenfeld)
Coffee is one of the most consumed beverages in the world, so it is not surprising that thousands of studies have already been conducted on its advantages and disadvantages.
New findings from a small study published Thursday in The New England Journal of Medicine suggest both upsides and downsides: Drinking at least one cup of coffee a day may make you move more but sleep less — and that could put you at higher risk for one common heart disease.
"Our findings show that there is not just one health-related outcome of coffee consumption, but that the reality is more complex than that," study lead author Dr. Gregory Marcus, a cardiologist and professor of medicine at the University of California, San Francisco, told CNN.
More active, less sleep
"The vast majority of research on the subject has been observational, meaning we just look and see what happens to people who drink and don't drink coffee, which limits the research greatly," Marcus said.
"The only way to mitigate the potential confounding effects was to conduct a randomized intervention trial."
To get a better idea of coffee's immediate health effects, the authors recruited 100 healthy adults who were an average of 39 years old and from the San Francisco area.
They equipped participants with Fitbits to track their steps and the length and quality of their sleep, in addition to a continuous blood glucose monitor and electrocardiogram devices that track their heart rate.
Each participant was randomly told to drink as much coffee as they wanted for two days, then abstain for two days, and repeat this over a two-week period.
On coffee-drinking days, participants walked an average of 1,058 more steps than on abstinent days, the authors found.
But on those days, sleep took a hit, with participants sleeping 36 minutes less.
The more coffee they drank, the more they exercised and the less they slept.
Iced coffee with milk (Photo: ShutterStock)
The coffee seemed to affect the heart as well.
Researchers found no evidence of a significant association between coffee consumption and atrial premature beats, which are "very common premature palpitations that we all experience that originate in the upper chambers of the heart," Marcus said.
They can feel like fluttering in the chest.
"People with atrial premature beats are at a higher risk of developing a clinically significant heart rhythm disorder called atrial fibrillation," he added.
But drinking more than one cup a day resulted in an approximately 50% higher incidence of ventricular premature beats, compared to days without coffee consumption. These arise from the lower chambers of the heart, and can also feel like a palpitation or palpitations. "So this provides some compelling evidence that coffee break trials may be worthwhile in those people who experience troublesome palpitations associated with premature ventricular beats," Marcus said.
"There is also evidence that in some people, more premature ventricular beats can lead to weakening of the heart or heart failure," Marcus added.
"So it could be that if someone is particularly concerned about the risks of heart failure - if, for example, they have a family history of heart failure or there is another indication that their doctor says puts them at risk - they may want to stay away from coffee."
Nutrition and diet