The effect of different doses of caffeine on time to exhaustion and ventricular repolarization parameters at rest and immediately after the exhaustion in young men

Caffeine is a most widely consumed physiological stimulant worldwide. The present study was conducted to identify the effect of different doses of caffeine on time to exhaustion, Heart rate, QT and QTc interval in young men.
Thirty Healthy students in a randomized double-blind design were allocated into Three Low doses of caffeine(2.5 mg/kg), moderate doses of caffeine(5 mg/kg) and placebo groups. Exercise protocol included exhausting running on treadmill(Using bruce test). Subject's electrocardiogram was recorded by electrocardiograms sport, in three stages (before, 45 minutes after taking caffeine and immediately after exhaustion). Data was analyzed by ANOVA and repeated measure ANOVA at α ≤ 0.05.
Time to exhaustion significantly increased in both caffeine groups (2.5 mg/kg and 5 mg/kg) compared to placebo group(P≤0.05). Heart rate, QT and QTc interval Were not significant differences in three groups of study at rest (45 minutes after taking caffeine) compared to baseline and at rest and immediately after the exhaustion the three groups.
Considering the results of the current study, Both low and moderate doses of caffeine can increase endurance performance in healthy young men. But do not a devastating impact on ventricular repolarization parameters. more research is necessary, to draw firm conclusions.