Caffeine

Caffeine has for many years been used to help increase energy during exercise. There have been a wide range of studies looking at its effect on both the aerobic system, (1), and the anaerobic system, (2), with most studies use dosages between 5-7 mg.kg.

Although the true nature of how caffeine affects the body is yet to be fully determined it has been suggested that it can modulate central fatigue to attain greater use of fats as an energy source, thus sparing muscle glycogen, (3). One particular study observed 98 participants over an 18 km race and found a faster time in participants who took caffeine over the control group, (4).

In terms of its use with anaerobic exercise (strength and power), it is suggested that caffeine can help improve motor recruitment which can help especially with lower body exercise where large muscle groups are used, (5).

+ Can prolong exercise                                                                          – Too much caffeine can be fatal                                                    + Lower perceived fatigue                                                                    – Can lead to addiction                                                                      + Increase recruitment of motor units                                              – Can cause irritation if taken in excess

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1 Wiles, J. D, Bird, S. R, Hopkins, J. & Riley, M. (1992). Effect of caffeinated coffee on running speed, respiratory factors, blood lactate and perceived exertion during 1500-m treadmill running. British journal of sports medicine, 26 (11), 116-120.

2 –  Kalmar, J. M & Cafarelli. E. (1998). Effects of caffeine on neuromuscular function. Journal of Applied Physiology, 87(2), 801-808.

3 – – Costill, D. L., Dalasky, G. & Fink, W. (1978) Effects of caffeine ingestion on metabolism and exercise performance. Journal of Medicinal Science and sports exercise, 10 (3), 155–158.

4 – Van Nieuwenhoven, M. A., Brouns, F. J. P. H., & Kovacs, E. M. R. (2005). The effect of two sports drinks and water on GI complaints and performance during an 18-km run. International journal of sports medicine, 26(04), 281-285.

5 – Warren, G. L., Park, N. D., Maresca, R. D., Mckibans, K. I., & Millard-Stafford, M. L. (2010). Effect of caffeine ingestion on muscular strength and endurance: a meta-analysis. Medicine & Science in Sports & Exercise, 42(7), 1375-1387.