Affects of caffeine on running performance

It has been known for some time that caffeine has the capability to affect endurance performance. In the past, caffeine has been accredited with the ability to enhance fat burning, but more recently attention has been focussed towards its potential effects upon the central nervous system (CNS).

Several studies have set out to determine if caffeine in some way “dampens” the pain signals during exercise, allowing athletes to compete harder. Much research is currently focussed upon the “central governor theory” which suggests that our brain is primarily responsible for deciding when we slow down. If this is the case, some stimulants may allow us to perform at a higher rate by “scrambling” messages within the CNS.

Bridge (2005) set out to determine if caffeine ingestion would benefit runners over a distance of 8km. Run time, perceived exertion, heart rate and lactate levels were monitored and results analysed. The study involved athletes racing on a track, as opposed to testing in a lab. They completed the 8km on three different occasions, consuming either 3mg of glucose per kg bodyweight, 3mg caffeine per kg bodyweight or a placebo.

Findings
Following caffeine ingestion, athletes ran an average of 23.8 seconds faster (these athletes were competitive runners, averaging approx 6 minutes per mile). Lactate levels and heart rate were slightly higher following caffeine ingestion and perceived exertion was slightly lower (although not statistically significant).

So they ran 23.8 seconds faster, but had higher lactate – does that make sense? We associate lactate with pain and failure to make our muscles work – how can lactate be higher and performance be better?

One possible explanation is CNS control, when lactate levels and heart rate rise to a large extent, the brain detects these changes and may inhibit your muscles by reducing signals via motor nerves. It’s a protection mechanism to stop you “frying” yourself. Maybe the caffeine “raised the bar”, allowing higher lactate and heart rate, before theon the runners. An important thing to note is that although lactate and heart rate were higher, “perceived exertion” was lower!

Conclusion
There’s increasing evidence to suggest that caffeine may help you to improve performance, if taken in the correct form and dosage.


* Taken from Bridge et al (2005) The affect of caffeine ingestion on 8km run performance in a field setting. Journal of Sports Sciences 2006, 1-7.


About the author of this training article
Marc Laithwaite, is Sports Science & Coaching Director, at The Endurance Coach. Mark has a Bsc (Hons) sports science and is working towards his Phd sports science. He is a member of the British Association of Sports and Exercise Scientists (BASES), a British Cycling Federation Blood Analyst, BTF Level 3 Coach & Coach Educator, UKA Level 3 Coach and ABCC Level 3 Coach.

The Endurance coach, provides sports science and coaching support services for endurance athletes. Their services include VO2 max testing, lactate profiling and metabolic assessment for endurance athletes of all standards in their own sports testing lab. The Endurance Coach also runs a range of training camps throughout the year and offers physiotherapy and rehabilitation services. For more information or if you are looking for world leading coaches to assist you, e-mail The Endurance Coach.

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