Acute Cardiovascular Effects of Turkish Coffee Assessed by VO₂ Test: A Randomized Crossover Trial

Turkish coffee (TC), a traditional unfiltered coffee preparation method, contains unique bioactive compounds due to its specific brewing process. While TC's cultural significance is well-documented, its acute physiological and psychological effects remain understudied.

This randomized, controlled crossover trial investigated the acute effects of a standardized TC dose (3 mg caffeine/kg body weight) on metabolic and psychological parameters in healthy female university students (n = 52, age: 20.25 ± 1.20 years).

TC was prepared with a 1:1 ratio of medium and dark roasted Arabica beans. The chemical analysis showed the caffeine content to be 2.8 ± 0.3 mg/mL and the chlorogenic acid content to be 1.9 ± 0.2 mg/ml. Participants were randomized to receive either TC or water control, with a washout period of 8 weeks between treatments. Cardiovascular parameters, metabolic markers, and validated visual analog scales (VAS) were assessed at baseline, 60-, 90-, and 120-min post-consumption.

Heart rate showed significant time-dependent reductions in both groups (control: p < 0.05; TC: p-value < 0.01 at 60, 90, and 120 min vs. baseline). Heart rate dropped significantly in the Turkish coffee group, from 78.0 ± 10.2 bpm at baseline to 71.5 ± 9.5 bpm after 90 min (p-value = 0.002). Sleep scores also declined, from 4.38 ± 2.91 at baseline to 1.88 ± 1.45 after 120 min (p < 0.05), indicating a stimulating effect of caffeine. TC consumption significantly affected appetite sensations (p < 0.05) and sleep scores (F = 3.174, p-value = 0.029), with the TC group showing progressive reductions in sleep scores from baseline (4.38 ± 2.91) to 60 min (2.58 ± 2.04), and further decreases at 90 and 120 min.

These findings suggest that TC exerts significant acute effects on cardiovascular function and psychophysiological parameters in healthy young females, potentially due to its unique phytochemical profile and preparation method.