The great coffee debate: harmful or beneficial?

Coffee is single-handedly the most consumed beverage worldwide, and there is a long-standing debate on whether it is beneficial or harmful to our health. It turns out, the answer is not simple. A new study from the American Heart Association has found that, in the short term, coffee has both harmful and beneficial effects.

The study has revealed that while coffee consumption does have negative side effects such as abnormal heart rates and reduced sleep duration, it also reduces the frequency of supraventricular tachycardia episodes in addition to increasing overall physical activity.

“While the majority of long-term observational studies have suggested multiple potential benefits of drinking coffee, this is the first randomized trial to investigate the real-time, physiologic consequences of coffee consumption,” explained study lead author Gregory Marcus.

The ambivalent conclusion resulted from the ECG tracking of 100 adult volunteers, with a particular focus on physical activity and sleep. 

The study participants, who had an average age of 38, were randomly assigned to either consume or avoid coffee for two consecutive days over a two-week period. The ECG monitor had a button to indicate the specific beverage, and trips to coffee shops were also noted through GPS tracking. 

Finally, questionnaires were conducted daily in order to assess exactly how much coffee the participants had consumed.

Coffee consumption ultimately resulted in conflicting heart-rate data, showing a correlation with a 54 percent increase in premature ventricular contractions or “skipped heartbeats,” despite reducing the number of episodes of supraventricular tachycardia. 

Coffee drinkers also tended to log an additional 1,000 steps than they would otherwise, yet also had 36 minutes less of sleep on average. Whilst the positive and negative effects were balanced, the results also showed that participants who minimized the amount of coffee they drank presented more positive changes than negative.

“More physical activity, which appears to be prompted by coffee consumption, has numerous health benefits, such as reduced risks of Type 2 diabetes and several cancers, and is associated with greater longevity,” explained Marcus. “On the other hand, reduced sleep is associated with a variety of adverse psychiatric, neurologic and cardiovascular outcomes.”

“More frequent abnormal heartbeats from the upper heart chambers influence risk of atrial fibrillation, and more frequent abnormal beats from the lower chambers, or ventricles, increase the risk of heart failure. These results highlight the complex relationship between coffee and health.”

The research was presented at the American Heart Association Scientific Sessions 2021.

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By Calum Vaughan, Earth.com Staff Writer