Coinciding exercise with peak serum caffeine does not improve cycling performance.

Area of Science:

• Exercise Physiology
• Nutritional Science
• Sports Performance

Background:

• Caffeine is a widely used ergogenic aid in sports.
• The optimal timing of caffeine ingestion for endurance performance remains debated.
• Previous research suggests a performance benefit from caffeine, but timing strategies vary.

Purpose of the Study:

• To determine if timing peak serum caffeine concentration with exercise onset enhances endurance performance.
• To compare the ergogenic effects of caffeine ingested 1 hour before exercise versus at peak concentration.

Main Methods:

• Randomized, double-blind, placebo-controlled crossover study with 14 male cyclists/triathletes.
• Participants ingested 6 mg/kg caffeine or placebo 1 hour before (C(1h)) or at peak serum concentration (C(peak)).
• Performance was assessed via a 40 km time trial; peak serum caffeine was determined through a separate profiling session.

Main Results:

• A significant 2.0% improvement in 40 km time trial performance was observed in the C(1h) condition compared to placebo (p=0.002).
• No significant performance improvement was found in the C(peak) condition versus placebo (1.1%; p=0.240).
• Higher plasma glucose, norepinephrine, and epinephrine concentrations were noted post-exercise in the C(1h) trial.

Conclusions:

• Caffeine ingestion 60 minutes prior to exercise significantly enhances 40 km time trial performance.
• Timing caffeine intake to coincide with peak blood concentration at exercise onset does not improve endurance performance.
• The ergogenic effect of caffeine is not directly related to achieving peak serum concentration at the start of endurance exercise.