Caffeine for Sports Performance
||Burke L, Desbrow B, Spriet L
| Year Published:
Caffeine for Sports Performance is a thorough review of research on how caffeine affects athletic performance.
Recommended for: Competitive Athletes. Although it is intended for advanced athletes, the content is fairly academic. Thus, some readers might find this book too scientific.
ABOUT THE AUTHORS
• Louise Burke is listed as a "professor" and "sports dietician." Since 1990, she has served as the head of sports nutrition at the Australian Institute of Sport and the team dietician for the Australian Olympic team from 1996-2012. Burke is also director of the International Olympic Committee diploma in sports nutrition and is a member of the Nutrition Working Group of the IOC.
• Ben Desbrow, PhD is a sports dietician and associate professor at Griffith University in Queensland, Australia. He completed his PhD in 2008, researching the effects of cola beverages on endurance exercise performance. In 1999, he was awarded the first Nestle Fellowship in Sports Nutrition at the Australian Institute of Sport. Since then, he has worked with many sports groups, including the 2000 British Olympic team and the Australian Institute of Sport Cricket Centre of Excellence.
• Lawrence L. Spriet, PhD is a professor in the department of Human Health and Nutritional Sciences at the University of Guelph in Ontario, Canada. Dr. Spriet received his BS in kinesiology, his MS in exercise physiology, and his PhD in medical sciences. He has published extensively in the field of sports nutrition, exercise physiology, and athletic performance.
This 205-page text is organized as follows:
- Chapter 1: A Brief History of Caffeine in Sport
- Chapter 2: How Caffeine Works
- Chapter 3: Finding Caffeine in Our Diets
- Chapter 4: Caffeine Use in Daily Life
- Chapter 5: Effectiveness
- Chapter 6: Known Side Effects, Health Risks, and Cautions
- Chapter 7: Permissibility of Caffeine Use in Sport
- Chapter 8: Recovery and Other Considerations
- Chapter 9: Individual Considerations for Caffeine Use
- Chapter 10: Putting It All Together
The authors have done a pretty thorough job of summarizing current scientific research on how caffeine affects athletes and athletic performance.
The Preface briefly summarizes what each chapter contains. While this book is appropriate for both athletes and academics, the content is fairly scientific in nature. This may not appeal to some athletes.
Chapter 1 focuses on the history of caffeine use. This chapter is only 4 1/2 pages and is weak. The discussion on p. 2-3 provides mostly useless trivia, while omitting other details that would be more relevant....for example, in addition to stating that coffee, tea, and cola drinks are the 3 biggest sources of caffeine in the human diet, why not provide per capita usage stats for these 3 beverages? (The authors list country-specific usage data on coffee, tea, cocoa, and yerba mate in chapter 4, but this table does not include stats on cola drinks.) The section titled "History of Caffeine Use in Sport" discusses caffeine research more than caffeine usage. Which types of athletes use the most caffeine? cyclists? triathletes? These data are not provided here. Absence of any discussion of energy drinks is another notable omission. The last paragraph in this chapter recognizes Dave Costill as an important researcher in this field, however, the bibliography for this chapter doesn't cite any of his publications.
Chapter 2 provides 14 pages that discuss the metabolism and pharmacologic actions of caffeine. There is good information here, but clarity could have been enhanced by also providing a table summarizing the salient pharmacologic properties of caffeine in bullet points, ie., one list of cellular effects and another list of clinical/performance effects. The authors explain that the performance-enhancing effects of caffeine are mostly due to its actions in the brain and CNS. This is a good discussion; the authors devote 5 pages to this. However, it would have been helpful to compare the CNS actions of caffeine to other well-known CNS stimulants such as amphetamine, methylphenidate, and modafinil. This could have been done succinctly in a table as well. In addition, the effects of using caffeine with sympathomimetics such as ephedrine should be discussed as this combination can be risky, ie., hypertension, hyperthermia.
Chapter 3 provides 26 pages discussing dietary sources of caffeine. There is a lot of good information in this chapter. Several tables summarize the caffeine content in specific coffees, teas, energy drinks, and sports supplements. However, I was disappointed that the authors did not clarify the caffeine amounts of some of the most common herbal sources of caffeine: eg., guarana, kola nut, etc. This information is not easy to find, even for academics. It would be relevant because of the explosion in the popularity of energy drinks. Many of these beverages do not list the amount of caffeine on the label, instead, only stating the amount of the herbal substance. At the end of this chapter, the authors present a comparison of actual vs. stated caffeine amounts in various coffee drinks in Australia. This is useful because these data are not widely known.
Chapter 4 is 19 pages and discusses caffeine usage. The first 12 pages discuss usage in the general population and by military personnel. Most of this content is extraneous and inconsistent with the title of the book. Table 4.1 provides usage data for coffee, tea, cocoa, and yerba mate in 42 countries. The decision to include yerba mate in lieu of cola drinks in this table is odd: only 3 countries consume yerba mate in any significant quantity, whereas, according to chapter 1, cola drinks are the 3rd largest source of caffeine worldwide. In various places (p. 69, p. 131) the authors mention athletes who use cola drinks for their ergogenic properties, so, this is another reason to provide data on cola drinks. Also odd: stats are provided for small countries like Ivory Coast and United Arab Emirates while no data are provided for countries well-known for coffee consumption such as Cuba, Jamaica, Puerto Rico. Regardless, considering the title of this book, it would be more appropriate to detail caffeine usage by specific sports, not by country. The remaining 7 pages discuss caffeine usage by athletes. This section begins to provide a perspective on how much caffeine is used by various categories of athletes. This is revealed by summarizing urinary caffeine concentrations of various types of athletes. This chapter should also discuss the usage of energy drinks (eg., Monster, Red Bull), and caffeine-containing sports gels (eg., GU) by athletes.
Chapter 5 is one of the most important chapters. It summarizes published research on the effectiveness of caffeine in various sports. Over 100 studies are reviewed. The authors group them into 5 categories: (1) endurance, (2) high-intensity, (3) stop-and-go, (4) strength and power, and (5) skill sports. These tables occupy 16 pages. In my opinion, 2 changes would make these tables easier to use: (a) In the left-most column, instead of listing the citation, list the name of the sport, using the fewest words possible (ie., "cycling" as opposed to "well-trained cyclists"). (b) Combine the "Measurement of Sports Performance" and the "Was It Enhanced?" columns and call it "Results" and summarize the effect on performance with the consistent use of standardized descriptors (eg., "aerobic performance", "strength", "timed performance", "muscle endurance", "reaction time", etc.). These changes would make it easier for a reader to compare research that studied similar groups or measured similar parameters. The "Technical Comments" column should be renamed "Limitations" and the text presented here should be reduced by using bullet points. Nevertheless, there is a lot of good information in these tables.
Chapter 6 discusses side effects of caffeine. This is also an important chapter, but, unfortunately, it comes up a bit short. On pages 97-99, case reports of caffeine overdoses are summarized. However, the authors' names and the year published are not provided for any of these reports. Although the citation is listed in the bibliography for this chapter, it is frustrating to try and determine which citation pertains to a specific discussion point. Further, when summarizing reports of caffeine toxicity, careful attention should be paid to whether the subject(s) also ingested sympathomimetics (amphetamine, ephedrine, modafinil, phenylpropanolamine, pseudoephedrine, etc.) The combination of caffeine with ephedrine has been shown to cause serious increases in blood pressure and body temperature (ie., the death of Baltimore Orioles pitcher Steve Bechler.) Combining caffeine with other CNS drugs or herbal supplements that contain sympathomimetics (eg., Citrus aurantium) may pose similar risks.
Chapter 7 discusses how sports governing groups have dealt with caffeine regarding its status as a performance-enhancing substance. This chapter is thorough and done well.
Chapter 8 discusses "recovery." It seems odd to place a discussion of the diuretic properties of caffeine here. This discussion would be more appropriate in chapter 2 (pharmacologic actions) or chapter 6 (side effects). Regardless, the authors do a good job of debunking the myth that caffeine causes dehydration by summarizing several good studies.
Chapter 9 is titled "Individual Considerations." There is good info here, though many different topics are addressed. The sections discussing placebo effect associated with caffeine, trained vs. untrained subjects, and sex differences are good discussions, but these would be more appropriate for chapter 5 where the bulk of the exercise performance research is reviewed. The section "Caffeine Withdrawal" seems like it would be more appropriate for the chapter on side effects (chapter 6). The authors also discuss the use of caffeine with other supplements. The discussion of how caffeine interacts with creatine supplements is an intriguing topic. The authors should expand this discussion as there appear to be differences between the effects of caffeine on creatine supplements vs. the effects on endogenous muscle creatine.
Chapter 10 is titled "Putting It All Together." I think this chapter could have been improved by restating some of the conclusions of how caffeine affects performance in the 5 groups of athletic activities used for the tables in chapter 5. For example, caffeine appears to be ergogenic for middle-distance and distance running, but not helpful for sprint running. For each of the 5 groupings in chapter 5, bullet point statements should be offered. Some guidance on dosage and timing should be provided. While this may be perceived as an endorsement, on the other hand, it might also prevent some toxicity in athletes who use too much caffeine.
• Photos & Illustrations: This book doesn't contain any photos or illustrations.
• Tables & Graphs: There are quite a few tables throughout this book. Generally, these are well done.
• Documentation / Accuracy: The authors cite roughly 300 publications. This is a good thing. However, numerous instances were discovered where (a) their discussion of research did not provide the authors' names and the year published, thus making it very difficult to determine which paper they were summarizing, and (b) sometimes a study that was summarized in the text was not included in the bibliography for that chapter. Since all 3 authors are veteran academics, this sort of sloppiness shouldn't occur. Copy editors may not have the time or skill to uncover these omissions. While this may seem like nit-picking, most, if not all, academic readers often want to review the original research.
• What I Liked: Even though the book is fairly academic, it is, nonetheless, easy to read.
• What Could Be Better: As noted above. The major critiques include: delete much of the discussion pertaining to use of caffeine by the general public; include more sports-specific and product-specific (eg., energy drinks, sports gels) content; improve the design/layout of the tables in chapter 5 to aid their usefulness.
In summary, Caffeine for Sports Performance is a pretty good review of scientific research on how caffeine affects athletic performance. It is easy to read. A major flaw with this book is that the authors devote too much content to the use of caffeine by the general public. This content goes beyond what the title suggests.
Conversely, the authors do not provide enough discussion on the specific caffeine products that different types of athletes use....ie., what percentage of body-builders use energy drinks? what percentage of triathletes use caffeine-containing gels? The authors do attempt to report on caffeine usage in specific sports by presenting data on urinary caffeine concentrations. However, they also present a convincing argument on p. 10 that urinary caffeine tests are highly unreliable. In addition, in several discussions the authors suggest that very low or undetectable caffeine concentrations might still be ergogenic. This raises questions: are caffeine mouth rinses simply a placebo effect? are urinary caffeine levels useless, and, if so, should they be eliminated as a test in competition? should blood levels be explored?
Despite some of the deficiencies noted above, I can recommend Caffeine for Sports Performance. It does contain good information. A 2nd edition that addresses the concerns raised above would make this book the de facto resource on the use of caffeine in sports.
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|Reviewed by: Stan Reents, PharmD
||6/2/2014 2:10:28 PM