The effects of caffeine on ambulatory blood pressure, heart rate, and mood in coffee drinkers

The present study examined the effects of caffeine as typically ingested through coffee, on ambulatory systolic and diastolic blood pressure (BP), heart rate, and mood. Normotensive coffee drinkers wore a BP monitor for two 24-hr periods, consuming decaffeinated coffee. Each cup was supplemented with 125 mg caffeine or cornstarch. Systolic and diastolic BPs were elevated on the day caffeine was consumed (maximum, 3.6 and 5.6 mm Hg, respectively), most notably shortly after ingestion. Heart rate was higher overnight following caffeine consumption Negative Affectivity was also increased by caffeine, but Positive Affectivity and tiredness were unaffected.