The Effect of Caffeine Ingestion on the Rating Perceived Exertion and Heart Rate during Exercise

This study aims to find out the effect of ingestion of 3㎎·kg-1 caffeine on rating perceived exertion (RPE) and heart rate (HR) during exercise under heat environment of 30~32℃ (40-50% humidity). Five trained males who routinely trained for approximately 60min·d-1, 3-6d·wk-1 (age; 28.20±3.56yrs, height; 174.56±5.46cm, body mass; 76.13±9.02kg, body fat; 14.24±3.99% VO2max; 54.00±4.30㎖·kg-1·min-1, exercise career; 4.20±1.95yrs, heart rate; 74.4±5.27beat·min-1) performed 40min of treadmill running in heat chamber. The study was a double-blind, randomized, crossover in design. There are three groups; control (CON), placebo (PLAC), and caffeine (CAFF). Caffeine ingestion significantly decreased in RPE during exercise compared with CON. CAFF displayed the lowest heart rate and increase ratio (125%), but there was no significant differences between the groups (p=0.560). In conclusion, it was confirmed that the consumption of caffeine prior to exercising under high temperature environment does not impart negative effect on HR and it may lower the cognition of fatigue from exercise.