Caffeine and Running Performance – The Latest Research

My articles the last few weeks might have been a bit disappointing if you are looking for a quick and easy way to boost your performance.

We saw that abdominal exercises aren’t all they’re cracked up to be (though hip strength is underrated), and the newfangled compression gear popular in running stores today might squeeze out a marginal benefit, though that’s not certain.

But the good news is that we’re looking at a reasonably reliable performance-booster today: caffeine! Caffeine has long been known to increase endurance, but the details of how, why, and when it can boost endurance are being revealed in some clever new studies published in the last few years.

The Research Behind Caffeine for Runners

Caffeine and exercise perception

The first study we’ll look at was done by Susan Backhouse et al. at Leeds Metropolitan University in the United Kingdom.1  Her study attempted to figure out whether the performance boost from caffeine has psychological roots.

Twelve “trained” men who had abstained from caffeine for three days were given a baseline endurance test on an exercise bicycle, as well as a psychological quiz to estimate how “aroused” (i.e. energized) they felt and to gauge their overall mood before and after the endurance test.  The subjects then participated in two 90min trials: one in which they were given caffeine beforehand, and one in which they were given a placebo.  Again, they were administered the “mood quiz” before and after each test.

Interestingly, physiological markers like oxygen consumption and heart rate were no different between the “caffeinated” and “decaffeinated” trials, but the cyclists’ perceptions were markedly different.  In psychologist-speak, they reported feeling more aroused and having a more pleasurable mood—in normal-speak, they felt better.

Unfortunately, for some reason this study didn’t actually measure raw performance in the exercise trials, so we’ll have to turn elsewhere to see if the caffeinated athletes really were performing better or just felt like it.

Caffeine and running performance

Fortunately, a study published just a few weeks ago by Todd Astorino and other researchers at California State University addresses the issue of whether caffeine actually helps athletes perform better.2

Using a similar procedure to Blackhouse et al., sixteen men (eight of them trained athletes, eight of them recreational athletes) completed two 10km cycling time trials, one after consuming caffeine, and one after consuming a placebo.

Unlike the previous study, arousal was not significantly different, but both groups reported feeling better vs. the placebo condition, although only the recreational athletes’ reports reached statistical significance (despite the averages of the two groups being very similar—alas, the problems of small sample sizes!).

More importantly though, this study found that performance increased by 0.3-2.0% over the 10km time trial (corresponding to about a 4-24 second improvement).

How much caffeine is optimal

Both of the previous studies used doses of 5-6 mg/km of caffeine—that’s milligrams of caffeine per kilogram of body weight, so 6 mg/kg would work out to 360 mg of caffeine if you weigh 60kg (132 pounds).

For reference, that’s three cups of coffee, which has somewhere in the neighborhood of 120 mg of caffeine per cup.  That’s quite a bit of coffee, enough to cause some serious pre-race jitters if consumed an hour before a race or workout, as was the protocol in these studies.

Can you get away with less?

Whether caffeine’s effects on performance are dose-dependent(i.e. increase with larger doses) was the subject of another study published last month by Ben Desbrow et al. at Griffith University in Australia.3  His study used sixteen well-trained cyclists who underwent three 60min cycling time trials: one control, one after a 6 mg/kg dose of caffeine, and one after a 3 mg/kg dose.

Fortunately for the jitter-averse, Desbrow et al. found a 3-4% improvement in both caffeine dosesover the placebo, but no significant differences between the doses.

Desbrow’s study also asked the participants to rate their perceived exertion levels and found no difference between the different dosage levels.  So the subjects always felt they were giving the same effort, but in the “caffeinated” state, they ended up going faster!

Does caffeine have the same effect on those runners who are caffeine addicts

One common criticism of research into caffeine and performance is that researchers are essentially measuring the detrimental effects of caffeine deprivation: since 90% of the population consumes caffeine in some amount on a daily basis, and since most studies require participants to abstain from caffeine for several days prior to the endurance test, the “control” group is really a caffeine-deprived group, which could skew results because caffeine withdrawal may reduce performance.

Until March of last year, no studies had confronted this criticism. Luckily, the research group at Griffith University turned out another study which used quite a clever design to address this issue.4

Twelve well-trained cyclists undertook four experimental trials.  For each trial, the subjects abstained from all dietary sources of caffeine for four days.  Each of these days, they were instructed to consume capsules given to them by the researchers, which contained either a placebo or caffeine, depending on the trial.

On the day of the endurance test (a 60min cycling time trial), the subjects were given another capsule to consume before the test, which was again either a placebo or caffeine.  So, there were four separate conditions: two in which the subjects were deprived of caffeine for four days, and two in which they were not. This design allowed the researchers to determine whether the performance “boost” was really a performance drop due to caffeine deprivation.

The results were good news for coffee drinkers: In both cases (caffeine deprived and not), a 3 mg/kg dose of caffeine improved endurance by about 3% vs. the placebo.  And whether the subjects were caffeine deprived or not made no difference in the performance boost!

Research short comings

However, there are still some shortcomings in all of these studies.  Small sample sizes are the bane of nearly all studies on caffeine and performance, and none of the ones we looked at today used actual runners.

Another reservation I have about all of these studies is that they were all essentially laboratory time trials.  I’d like to see some research done on runners in an actual race.  Maybe a jolt of caffeine just makes sitting on an exercise bike in a lab more bearable!

While we didn’t look at the specific ways caffeine can boost performance in this article, we have detailed the 6 ways caffeine can boost your performance here

How you can use caffeine

In any case, if you are looking for a quick way to boost performance, a large cup of coffee an hour or so before a race or workout just might do the trick.

If you do want to give it a shot, recall that Desbrow’s work showed that a dose of 3 mg/kg was just as effective as a larger dose.  So you can do the math if you want to get technical, or just drink a big mug of coffee—an average-sized runner would need between 1.5 and 1.75 standard 7-oz. cups of coffee (or about one 200mg no-doze tablet if you want to cut to the chase) to get the right dosage.

As with any “intervention,” it makes sense to test it out in a workout before you gulp down coffee before your next marathon, only to find yourself searching frantically for a port-a-potty five minutes before the race!

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References

1. Backhouse, S. H.; Biddle, S. J. H.; Bishop, N. C.; Williams, C., Caffeine ingestion, affect and perceived exertion during prolonged cycling. Appetite 2011, 57 (1), 247-252.
2. Astorino, T. A.; Cottrell, T.; Talhami Lozano, A.; Aburto-Pratt, K.; Duhon, J., Effect of caffeine on RPE and perceptions of pain, arousal, and pleasure/displeasure during a cycling time trial in endurance trained and active men. Physiology & Behavior 2012.
3. Desbrow, B.; Biddulph, C.; Devlin, B.; Grant, G.; S, A.-D.; Leveritt, M., The effects of different doses of caffeine on endurance cycling time trial performance. Journal of Sports Sciences 2012, 30 (2), 115-120.
4. Irwin, C.; Desbrow, B.; Ellis, A.; O'Keefe, B.; Grant, G.; Leveritt, M., Caffeine withdrawal and high-intensity endurance cycling performance. Journal of Sports Sciences 2011, 29 (5), 509-515.
5. O'Rourke, M. P.; O'Brien, B. J.; Knez, W. L.; Paton, C. D., Caffeine has a small effect on 5-km running performance of well-trained and recreational runners. Journal of Science and Medicine in Sport 2008, 11 (2), 231-233.

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