Australian reseachers find that timing matters

By Scott Douglas

That caffeine can boost endurance performance is well-known. It's logical, then, to think that the biggest boost comes when the caffeine reaches its peak concentration in your bloodstream.

But that's not what Australian researchers found in a study on caffeine timing and performance in a 40K cycling time trial. Writing in the Journal of Science and Medicine in Sport, they report that caffeine's biggest ergogenic (performance-enhancing) effect came about an hour after ingestion, although peak caffeine concentration in the cyclists' bloodstreams occurred two to two-and-a-half hours after ingestion.

In the study, experienced cyclists and triathletes ate a typical pre-workout meal, and later in the day did a 40-kilometre time trial under one of three conditions: an hour after taking a placebo, an hour after taking caffeine pills or when the caffeine concentration had peaked in their bloodstream, which was an average of 120 to 150 minutes after taking the caffeine pills.

Performance on the time trial increased by two per cent when the cyclists had caffeine compared to a placebo an hour before. But performance when the time trial coincided with peak caffeine concentration was no better than when they'd taken the placebo. This result surprised the researchers, whose hypothesis had been that doing the time trial coincident with peak serum (bloodstream) caffeine concentration would be the fastest result. They wrote:

“[A]chieving peak serum concentration prior to endurance exercise performance may not be as important as some other, as yet unknown, variable related to caffeine intake. Clearly, it is not the serum caffeine concentration per se that is important to the ergogenic potential of caffeine...”

For those of us without a means to measure peak serum caffeine concentration while sipping our morning coffee, this is good news. To get a performance boost from caffeine, have it about an hour before your workout.

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