Comparison between sprint and endurance swimming records in the morning and evening following caffeine consumption

Research has shown that the time of day to absorb caffeine is an intervention variable which should be considered when evaluating caffeine ergogenic. The purpose of this study is to comprise sprint and endurance swimming records on female swimmers in the morning and evening following consumption of caffeine.

Fourteen female swimmers (age 24.6 ± 4 years, BMI 23.10 ± 0.73 kg/m2) participated as volunteers in the Study. The study design was crossover and subjects were examined 8 times in 5-day intervals placed in either caffeine (6 mg/kg) or placebo (6 mg/kg). Swimming records for 50m and 400m free style were measured one hour after consumption of caffeine or placebo during morning and afternoon (8 am and 6pm).

Results indicated that there was a significant difference between the results of swimming performance of 50 m (speeding) at morning and afternoon and 400 m (endurance swimming) in the morning and evening hours (P<0.05). Caffeine supplement consumption has significant influence on the 50m and 400m free style during the mornings (P<0.05) whereas it was negligible during evenings (P>0.05).

Therefore it can be concluded that consumption of 6 mg/kg of caffeine during the morning can result in a significant increase in the sprint and endurance swimming records that suggesting consumption time of caffeine influence on performance independent of caffeine dose.