Hi everyone,

Who had a cup of coffee this morning? One of the reasons people consume 2.25 billion cups of coffee a day (1) is because of its caffeine content. Take college students for example – you drink a cup of coffee before a sports game and you see improved performance. Is it a coincidence? My friend last year used to drink an iced coffee before every baseball game saying that he hit more home runs doing so. Is it simply superstition? I wanted to find out for myself.

It is important to note that coffee and caffeine are not the same. Caffeine is present in coffee, but consuming pure caffeine has different effects on performance then when consumed via coffee (2). It was found in one study that consuming pure caffeine improved the endurance of high quality runners from 32 min (at 10 km pace) to 41 min, while consumption of regular coffee had no effect (3). Caffeine is a trimethylxanthine and is catabolized by the cytochrome P450 system in the liver to dimethylxanthines. Consuming pure caffeine correlated with expected increases in free fatty acids (FFA) and epinephrine which could be tied to performance (3). While this study suggested that pure caffeine improved endurance but coffee did not, other studies have found coffee to also be ergogenic (2).

Many studies have shown that caffeine can be ergogenic in endurance activities where fatigue sets in between 30 and 60 min (2). Even if fatigue is at 30 min, it is unlikely that muscle glycogen has been depleted. One study showed that over half of the muscle glycogen remained at fatigue at 30 min, suggesting it is not the limiting factor regarding endurance here (2). So what about for longer feats of endurance? Ivy et al. had individuals perform 2 hours of
cycle exercise and, after caffeine ingestion, the participants generated a 7.3% greater total power output (4). This is not the only study to show a similar result in long distance, endurance exercise – in fact there are many (2). So, what about short, high intensity exercise? Less consensus has been placed here – while one study showed improved high intensity endurance, another showed no difference in caffeine vs. non-caffeine subjected participants (2).

There is much more research to sort through – about strength, endurance, power, etc. For my presentation, I will continue to sort through this research, but it is already readily apparent that caffeine does affect human performance in some, if not all, athletic and exercise endeavors. It is even more interesting that the dosage of caffeine necessary to improve performance may be lower than the acceptable standards of performance enhancing drug regulation committees of the Olympics (2).

Overall, I am excited to continue to tackle this issue and conduct my own correlative/anecdotal studies – I will see if I can’t repeat some of these findings by seeing how drinking coffee before a workout affects my own performance. I also cannot wait to hear about everyone else’s topics!

1. Nieber, K. (2017). The Impact of Coffee on Health Author Pharmacokinetics and Mode of Action Bioactive Components in Coffee. Planta Medica, 83, 1256–1263. https://doi.org/10.1055/s-0043-115007
2. Graham TE. (2001). Caffeine and Exercise: Metabolism, Endurance, and Performance. Sports Medicine. (11):785-807.
3. Graham TE, Hibbert E, and Sathasivam P. (1998). Metabolic and exercise endurance effects of coffee and caffeine ingestion. Journal of Applied Physiology. 85(3):883-9.
4. Ivy JL, Kammer L, Ding Z. Wang B, Bernard JR, Liao YH, and Hwang J. (2009). Improved cycling time-trial performance after ingestion of a caffeine energy drink. International Journal of Sport Nutrition and Exercise Metabolism. 19(1):31-78.