Acute Effects of Coffee Consumption on Health

Quick Takes

  • Caffeinated coffee was not associated with an increase in atrial premature contractions, and a mild increase in premature ventricular contractions.
  • Caffeinated coffee was associated with approximately 30 minutes less sleep on a daily basis and a mild increase in daily steps.
  • No difference was noted in serum glucose levels.

Study Questions:

Is coffee associated with acute health effects?


CRAVE (Coffee and Real-time Atrial and Ventricular Ectopy) was a prospective, randomized, case-crossover trial to examine the effects of caffeinated coffee on cardiac ectopy, arrhythmias, daily step counts, sleep duration, and serum glucose levels. The study population included adults aged ≥18 years who consumed caffeinated coffee at least once a year, were willing to abstain from coffee for ≥2 consecutive days over a 14-day period, and owned a smartphone. Adults with a history of atrial fibrillation, heart failure, or who had an implanted pacemaker or defibrillator were excluded. Also excluded were those taking beta-blockers, non-dihydropyridine calcium channel blockers, or Vaughn-Williams class 1 or 3 antiarrhythmics.

Participants wore a continuously recording electrocardiogram device, a wrist-worn accelerometer, and a continuous glucose monitor. Participants also downloaded a smartphone application to collect geolocation data. Daily text messages were sent to participants over a 14-day period to randomly instruct them to consumer caffeinated coffee or avoid caffeine. The primary outcome was mean number of daily premature atrial contractions. Secondary outcomes included daily number of premature beats, episode of supraventricular tachycardia or ventricular tachycardia, daily step counts, minutes of sleep, and serum glucose levels. Adherence to the randomization assignment was assessed with the use of real-time indicators recorded by participants, daily surveys, reimbursements of data-stamped receipts for coffee purchases, and virtual monitoring (via geofencing) of coffee-shop visits.


A total of 100 participants were included in the study. The mean (± SD) age was 39 ± 13 years; 51% were women, and 51% were non-Hispanic White. The consumption of caffeinated coffee was associated with 58 daily premature atrial contractions as compared with 53 daily events on days when caffeine was avoided (rate ratio [RR], 1.09; 95% confidence interval [CI], 0.98-1.20; p = 0.10). The consumption of caffeinated coffee as compared with no caffeine consumption was associated with 154 and 102 daily premature ventricular contractions, respectively (RR, 1.51; 95% CI, 1.18-1.94); 10,646 and 9,665 daily steps (mean difference, 1,058; 95% CI, 441-1675); 397 and 432 minutes of nightly sleep (mean difference, 36; 95% CI, 25-47); and serum glucose levels of 95 mg/dL and 96 mg/dL (mean difference, −0.41; 95% CI, −5.42 to 4.60). Adherence to the random assignments was assessed to be high.


The authors concluded that consumption of caffeinated coffee did not result in significantly more daily premature atrial contractions than the avoidance of caffeine.


This well conducted trial suggests that caffeinated coffee is not associated with an increased risk for arrhythmias. It should be noted that the study population was relatively young and healthy.

Clinical Topics: Arrhythmias and Clinical EP, Prevention, Implantable Devices, EP Basic Science, SCD/Ventricular Arrhythmias, Atrial Fibrillation/Supraventricular Arrhythmias, Sleep Apnea

Keywords: Accelerometry, Arrhythmias, Cardiac, Atrial Premature Complexes, Caffeine, Cardiac Complexes, Premature, Coffee, Electrocardiography, Glucose, Primary Prevention, Sleep, Smartphone, Tachycardia, Supraventricular, Tachycardia, Ventricular, Text Messaging, Ventricular Premature Complexes

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