Effect of caffeine on exercise performance among untrained medical students

The purpose of the study was to examine the effect of moderate dose (5mg /kg) of caffeine ingestion on pulse rate, blood pressure and energy expenditure during a steady state e xercise period with a standardized power output as well as during a set time period.  In this study participants were required to cycle with maximum effort.  Eighteen  healthy, overweight, sedentary, male, first year  MBBS students of  JNMC,  completed 15 minutes of steady state of cycling  exercise  at a standardized  power output equating to 65% of HRmax. This was followed by 10 minutes stationary cycling where they were required to cycle with maximum effort after ingestion of caffeine (5mg/kg) 60 min prior to exercise. Same subjects were used as control.  The study showed an increase in systolic blood pressure after caffeine ingestion but there was no significant change in diastolic blood pressure.  Pulse rate decreased after caffeine ingestion, which indicates decrease in heart rate. After caffeine ingestion energy expenditure in the 2nd part (10 min maximal) of exercise increased but it significantly increased in the 1st part of exercise (15 min submaximal exercise).