Club member Ellen Reynolds is a Dietitian working at Warwick Hospital and in Leamington Spa. Has part of her focus on Sport Nutrition she has been studying the effects of caffeine on cycling performance. Read on to discover the fascinating insights from her recent research work.
While studying sports nutrition at Coventry university, I completed a research project exploring the effect of caffeinated coffee on the performance of a 10-mile time trial among female cyclists. Popular among elite and recreational athletes, Caffeine is one of the few dietary supplements with substantial research evidence supporting its use in cycling, boosting performance of aerobic endurance events  as well as high intensity and repeated sprint activities. However my own study found a lot of variation in participants’ responses to caffeine, with some demonstrating worsened TT performance upon caffeination. This reflects a common observation among existing research studies that not everyone responds positively to caffeine as an ergogenic aid. Individual responses are really important to consider if you are thinking of using caffeine to help optimise your own cycling performance.
What is Caffeine, and What Does it Do?
Caffeine is a stimulant naturally found in coffee beans, cocoa, cola nuts and tea leaves. Its isolated form is a white, bitter-tasting powder. It affects various bodily systems including hormonal, metabolic, cardiovascular, and respiratory functions, and there are several mechanisms of action proposed to explain its effects on exercise performance. In the central nervous system it acts as a competitor for receptors of adenosine, a signalling molecule in the body, leading to improved neurotransmission and reduced pain perception. Caffeine can also affect the body’s use of energy sources during exercise, such as increasing the use of free fatty acids as fuel and preserving muscle glycogen. Other mechanisms include increased calcium mobilization to improve muscle contraction speed and strength; phosphodiesterase inhibition, leading to accumulation of cell signalling molecules cAMP and cGMP, improving muscle and cardiac contractility; and increased activity of ion pumps in muscle membranes, enhancing muscle fibre contraction.
How Much Is Needed?
In general, a caffeine dose of between 3-6mg per kg bodyweight, taken 60 minutes in advance, is recommended to improve aerobic endurance performance. This is associated with an average performance improvement of 3.6% among time trials of 5-150 minutes in duration, however responses are highly variable between studies (ranging from −0.3% to 17.3% difference in performance), indicative of individual responses and differences in route of ingestion, timing, and habituation. Some people also benefit from lower doses of 2-3mg per kg – these lower doses can be taken during endurance events for prolonged performance benefit, and are associated with fewer side effects. Lower doses also appear to positively effect cognitive performance regardless of physiological effects. Meanwhile higher doses, above 9mg per kg, don’t appear any more beneficial, and may increase the risk of negative side effects such as nausea, anxiousness, insomnia, and restlessness.
How Can It be Taken?
Coffee may come to mind as a handy source of caffeine, with an 8oz brew providing around 95mg, however the amount in a cup, affected by the beans and preparation methods, can vary widely, making it hard to know how much you are actually ingesting. Alternatively it can be consumed in its isolated form as a capsule, or may be an ingredient in drinks, gels and bars, which can provide additional hydration and nutrition to support your performance.
If you are competing at a national or international level and considering sports foods and supplements, you are responsible for ensuring that the foods/drinks you consume are free of prohibited substances according to the World Anti-Doping Code. Sourcing certified products from an independent batch-tester (https://wetestyoutrust.com) will help minimise the risk of unintentional exposure to banned substances leading to an Anti-Doping Rule Violation.
Will Caffeine Work For You?
To see if caffeine will improve your own performance, test you own responses during training sessions – start with a lower dose, ~3mg per kg bodyweight, taken 60minutes before your session, and compare differences in performance of the same training session on different days with/without caffeine. Controlling variables between days such as dietary intake, hydration and time of day will generate more reliable results. Try different doses, routes and timings, and replicate the race day routine to help establish what works for you.
It is worth noting that most of the evidence for caffeine’s use to support exercise performance is generally conducted in young male participants, and it is possible that different hormonal and age-related physiological differences may contribute to different experiences in performance responses. Don’t be surprised if your own experiences with caffeine are wildly different!
A Final Note..
Remember that any performance benefits provided by dietary supplements such as caffeine will be small, and dwarfed by the importance of a dietary intake that meets your body’s requirements to perform optimally. Caffeine is no substitute for a sub-optimal nutritional strategy no matter how much you use. Feel free to contact myself (firstname.lastname@example.org) if you’d like any advice or support regarding nutrition to support your cycling performance.
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