Effects of acute caffeine supplementation on hemodynamic and cardiorespiratory responses during incremental aerobic exercise

Abstract

Objective: to analyze the effects of acute caffeine supplementation on hemodynamic and cardiorespiratory responses during incremental aerobic exercise. Methods: quasi-experimental, crossover, double-blind study with 10 physically active men (29.4 ± 4.2 years). Participants performed a treadmill (ramp) protocol under two conditions: caffeine (400 mg) and placebo, with a seven-day interval. Heart rate, blood pressure, double product, VO2max, and exercise tolerance (stages) were assessed. Results: caffeine supplementation significantly increased mean heart rate during the protocol (138.76 ± 11.69 vs.
131.33 ± 6.16 bpm; p=0.016) and resulted in higher diastolic blood pressure at peak effort compared to placebo (p=0.029; Δ=8.00 mmHg). No significant interactions were observed for systolic blood pressure, double product, VO2max (p=0.655), or number of stages achieved (p=0.196). Both sessions showed the expected physiological behavior of elevation and post-exercise recovery for heart rate and systolic blood pressure. Conclusions: acute ingestion of
400 mg of caffeine promoted greater cardiovascular overload, evidenced by an increase in mean heart rate and diastolic blood pressure at peak exercise, without, however, translating into improved maximum oxygen consumption or functional performance in active men.