The Acute Effect of Espresso Coffee and Caffeine on Measures of Cardiovascular and Cognitive Function, a Single Blinded Cross Over Study

Abstract

Coffee is one of the most popular beverages in the UK. This study investigated the acute effects of espresso coffee and caffeine on markers of cardiovascular health and cognitive performance. The study had two hypotheses: Caffeine and coffee would increase blood pressure and arterial stiffness; caffeine and coffee would improve cognitive function. Blood pressure (BP) and haemodynamic parameters of pulse wave velocity (PWV), heart rate (HR) and augmentation index (AIx) were measured. Cognitive function was analysed using four validated tests. There were three interventions: coffee, decaffeinated coffee and caffeine. Caffeine content corresponded to 1.5mg/kg bodyweight. Seven healthy female participants took part. Measurements were taken at baseline and 45 minutes post-intervention. Coffee and caffeine significantly raised PWV (P≤0.05), with values rising from 6.46±0.96m/s to 6.8±1.03m/s and 6.32±0.95m/s to 6.73±0.93m/s respectively. Caffeine significantly raised systolic BP (P≤0.05) from 108.67±7.92mmHg to 114.67±7.92mmHg. There was no significant effect on HR and augmentation index. All interventions significantly improved Stroop test performance (P≤0.05), coffee resulted in improvements from 26.55±7.39s to 23.5±7.98s, decaffeinated coffee from 25.7±5.44s to 21.80±4.69s and caffeine from 25.36±6.08s to 21.84±6s. Decaffeinated coffee significantly increased Corsi block tap test scores (P≤0.05), with mean scores improving from 42.86±16.23 to 61.87±19.05. An acute negative effect on central arterial stiffness following ingestion of both coffee and caffeine was observed in habitual consumers, with caffeine alone having a more detrimental effect on cardiovascular health. Only decaffeinated coffee induced positive results in every test and also had significant improvements in two out of four cognitive tests. This study shows the importance of considering both coffee and caffeine ingestion prior to analysing arterial stiffness. Neither hypothesis was fully proven: Caffeine alone has a more detrimental effect on cardiovascular health compared to coffee; coffee and caffeine did not increase overall cognitive performance in habitual consumers.