Dear Editor,

We read with great interest the article published in BJSM by Dickinson et al (February 2006) (1) on challenge methods for screening elite winter athletes for exercise induced asthma (EIA). We are in agreement with the commentary by Professor Rundell that this is a solid and clear paper reaffirming the efficacy of eucapnic voluntary hyperventilation (EVH) in diagnosing EIA. However, we believe that the negative findings observed by the authors in regards to the laboratory based exercise challenge may in fact be due to a number of procedural limitations of the method selected. Anderson and Holzer (2) assert that EIA is primarily determined via the level of ventilation achieved and sustained during exercise, which reflects the intensity of exercise and the water content of the inspired air; thus explaining recommendations for the 2006 Turin Winter Olympic Games (3) “that the exercise test should be performed breathing dry air for 8 minutes with the intensity of exercise close to maximal for the last 4 minutes.” Indeed, in our laboratory, when we conduct exercise challenge tests on elite athletes with physician- diagnosed EIA we typically exercise them to volitional exhaustion (4). Therefore the use of 90% of maximum heart rate for elite endurance athletes by Dickerson et al (1) does not seem to be an adequate intensity to allow them to ventilate at sufficiently high rates in order to elicit airway drying and hence evoke symptoms of EIA. Perhaps reporting the ventilation rates for each challenge would allow a better comparison of the different testing procedures.

In addition, Evans et al. (5) recently demonstrated that dryness of the test conditions rather than a cold temperature is essential to the EIB response. It is generally accepted that inhaling cold-dry air at high ventilation rates initiates EIA (4, 5). Rundell and coworkers (6) have shown that out of 23 subjects who tested positive for EIA in cold-dry air, 18 (78%) subjects tested negative in ambient conditions (21oC and 50% relative humidity). This suggests that the exercise protocol performed in ambient conditions in the Dickinson et al. (1) study may have been less sensitive to identifying changes in airway hyperresponsiveness following exercise due to inadequate environmental stress.

Sincerely,

Martin R. Lindley, Ph.D.

Timothy D. Mickleborough, PhD. FACSM.

Indiana University.

References

1. Dickinson JW, Whyte GP, McConnell AK, Harries MG. Screening elite winter athletes for exercise induced asthma: a comparison of three challenge methods. Br J Sports Med 2006; 40: 179-183.

2. Anderson SD, Holzer K. Exercise-induced asthma: is it the right diagnosis in elite athletes? J Allergy Clin Immunol 2000; 106: 419-428.

3. International Olympic Committee. Beta2 adrenoceptor agonists and the Olympic Games in Turin. 2005. http://multimedia.olympic.org/pdf/en_report_981.pdf (accessed 12 February 2006).

4. Mickleborough TD, Murray RL, Ionescu AA, Lindley MR. Fish oil supplementation reduces severity of exercise-induced bronchoconstriction in elite athletes. Am J Respir Crit Care Med 2003;168: 1181-1189.

5. Evans TM, Rundell KW, Beck KC, Levine AM, Baumann JM. Cold air inhalation does not affect the severity of EIB after exercise or eucapnic voluntary hyperventilation. Med Sci Sports Exerc 2005; 37:544-549.

6. Rundell KW, Wilber RL, Szmedra L, Jenkinson DM, Mayers LB, Im J. Exercise-induced asthma screening of elite athletes: field versus laboratory exercise challenge. Med Sci Sports Exerc 2000; 32: 309-316.

Dear Editor,

Having trained for, competed in, and served as ringside physician for numerous full-contact martial arts competitions, I took great interest in reading Dr. G.H. Bledsoe’s letter “Mixed martial arts not all bad.”[1] I appreciated his feedback regarding my article[2] and applaud his drive to research combat sports with utmost objectivity. Acknowledging the dangers of participation both from the perspective of a researcher and former fighter, I would like to address some of Dr. Bledsoe’s insights regarding mixed martial arts (MMA).

Dr. Bledsoe commented, “Sanctioning [of MMA] brought about many rule changes that mandated weight classes, time limits for rounds and matches, and eliminated many of the most dangerous techniques including stomps, head butts, and groin attacks.”[1] Unsanctioned until 2000, the United States-based MMA organisation (USMMAO) used in my study had already mandated rounds in 1995, weight classes in 1997, and “protective” MMA gloves shortly thereafter. Since its inception in 1997, the Japan-based MMA organisation (JMMAO) used in my study mirrored the same rules and regulations of the sanctioned USMMAO events. In addition, no matches in my study were stopped as the direct result of head butts (when legal) and 2 of the 642 matches (0.3%) were stopped due to stomps to the head. At the time this letter was released, head stomps remained a legal technique in the JMMAO despite sanctioning.

Dr. Bledsoe noted that MMA was sanctioned in September 2001. Although this referred to the first MMA event in Las Vegas approved by the Nevada State Athletic Commission, the New Jersey State Athletic Control Board was actually the first to sanction the sport in Atlantic City one year prior.

I compared match stoppages due to head impact in the USMMAO during 1993-1997 (MMA gloves not mandatory) to those during 1998-2003 (MMA gloves mandatory). Twenty-four of 120 matches (20.0%) were stopped due to head impact from 1993-1997, while 98 of 287 matches (34.1%) were stopped due to head impact from 1998-2003 (chi square analysis, p=0.01). Hence, mandatory wear of MMA gloves and subsequent sanctioning of USMMAO events were not associated with a reduction in match stoppages due to head impact. Sanctioned or not, the sport will remain inherently risky so long as the primary intent of the MMA encounter is to inflict trauma on one’s opponent.

Dr. Bledsoe stated, “The fact that MMA has no ‘standing eight count’ enabling a concussed participant time to recover and continue fighting is a tremendous step toward diminishing traumatic brain injury.”[1] The validity of this statement should be assessed via neuropsychological testing, neuroimaging, and/or neural biomarkers.[3,4] Since concussion (e.g., transient loss of consciousness following a blow to the head) does not reliably correspond to injury severity,[5] the MMA competitor that is removed from a match following concussion may receive no advantage in neuronal preservation over the boxer who continues fighting following a standing eight count. Independent of rules, blunt head trauma sustained among those who train and compete in MMA merits further research.

I look forward to reading the article by Dr. Bledsoe and colleagues,[6] as their work will serve to further elucidate those medical issues most salient to this burgeoning sport. I appreciate your objective consideration of the combat sports and, through our continued efforts, we will hopefully prevent undue morbidity and mortality.

Sincerely,

George J. Buse MD, CSCS

Department of Aerospace / Preventive Medicine, Cannon USAF Clinics, Cannon Air Force Base, New Mexico

References

1. Bledsoe GH. Mixed martial arts not all bad. Br J Sports Med, 9 Feb 2006, http://bjsm.bmjjournals.com/cgi/eletters/40/2/169 (accessed 15 Feb 06).

2. Buse GJ. No holds barred sport fighting: a 10 year review of mixed martial arts competition. Br J Sports Med 2006;40:169-72.

3. Erlanger DM, Kutner KC, Barth JT, et al. Neuropsychology of sports -related head injury: dementia pugilistica to post concussion syndrome. Clin Neuropsychol 1999;13:193-209.

4. Chen DQ, Zhu LL. Dynamic change of serum protein S100b and its clinical significance in patients with traumatic brain injury. Chin J Traumatol 2005;8:245-8.

5. McCrory P, Johnston K, Meeuwisse W, et al. Summary and agreement statement of the 2nd International Conference on Concussion in Sport, Prague 2004. Br J Sports Med 2005;39:196-204.

6. Bledsoe GH, Hsu EB, Grabowski JG, Brill JD, Li G. Incidence of injury in professional mixed martial arts competitions. The Journal of Sports Science and Medicine (in press).

Disclaimer: The views expressed herein are not to be construed as reflecting the policies of the United States Air Force or Department of Defense.

Reply: Right type of ball used in study

This is a forward-looking study in which modern day footballs were employed to assess the possible impact on the brain by heading. Old style heavy footballs, however, may well have been associated with brain damage as pointed out by Dr Breimer.

That the brains of woodpeckers would be full of plaques and signs of neuronal damage is a tall story. One case of cerebral amyloid angiopathy (a very common and unspecific ageing sign) has been reported in an aged great spotted woodpecker (Nakayama H, et al., Neurobiol Aging. 1999 Jan-Feb;20(1):53-6). In contrast, the woodpecker is very well adapted by evolution to repeated head blows by different anatomical structures that protect the brain (see May PR, et al., Lancet. 1976 Feb 28;1(7957):454-5; and Schwab IR, Br. J. Ophthalmol. 2002;86;843 for examples).

We are pleased that Dr. Shephard agrees with our views. In contrast to his retrospective assertions, dispassionate analysis of what he has written in the past shows that his conversion to our drinking guidelines has occurred only with the publication of his most recent letter.

Professor Shephard continues to be dismissive of most of the work of our Cape Town research unit [1, 2]. To our knowledge we have largely single-handedly led the battle against overdrinking [3-6] beginning with our 1985 paper [7]; we are not aware that Professor Shephard ever contributed to that campaign although we obviously welcome his belated support. To state that this is a “relatively new insight for investigators in Cape Town” is perhaps the most remarkable distortion to be published in the British Journal of Sports Medicine in the past 40 years that the senior author has been reading this journal. It brings to mind the famous statement to the effect that truth goes through three distinct phases. First other scientists say that what you claim is completely wrong. Next they acknowledge that your claim is indeed true but they continue to dismiss it as “completely irrelevant”. Finally they claim your truth as their own declaring that “we always said it anyway”. About six years ago Professor Shephard concluded that the drinking guidelines in Lore of Running [8] were completely wrong, perhaps dangerous. Now apparently he was the first to propose those identical guidelines “26 years ago”.

Our analysis of what appears in Professor Shephard’s book is not “totally incorrect”. His book is cited only once in our paper (table 1) [9]. The book does not provide a set of drinking guideline for athletes. Instead at different parts of the text, there are references that Professor Shephard now claims can be cobbled together to produce a set of drinking guidelines. For example his assertions 1 and 3 in his letter (pp. 42 and 72 respectively in [10]) are not drinking guidelines. Assertion 2 is also not written as part of a drinking guideline. Rather it appears as part of a review of previous work of fluid intake and runners. For example on page 43 of his book Shephard writes: “…Kavanagh and Shephard (1977a) followed middle-aged men over a 4- to 5-hr run; their group sustained a fluid intake of up to 630 ml.hr-1, the largest volumes again being ingested by those who were provided with pure water” [10]. Nowhere in his text does Professor Shephard define optimum rates of fluid intake during exercise, what we would consider a core component of responsible drinking guidelines. Of course providing specific drinking guidelines involves personal accountability and not everyone is prepared to accept that responsibility.

A more complete examination of the book reveals further examples of advice that is so vague that it is of little value. For example on page 42 Professor Shephard writes: “the water balance of a distance runner or team sportsman can be improved if he is preloaded with up to 500ml of fluid 15-30min before exercise commences. Further small quantities of fluid should be taken at regular intervals as exercise proceeds” [10].

Finally in contrast to Professor Shephard’s certainty that his book does not contain advice which would encourage athletes to “drink beyond thirst”, page 309 contains the following specific advice: “During exercise or heat exposure, thirst is not a sufficient indicator of fluids needs (Adolph, 1947)”. Thus Professor Shephard’s book like most of the other material that we reviewed, does indeed promote overdrinking.

In summary, one of the points of our article was to show how textbooks can perpetuate old and often out-of-date advice. Professor Shephard’s response extends that argument by showing that some authors are unaware of exactly what is in their own textbooks and how dated and incorrect that advice might be.

References

1. Shephard RJ. Do the Numbers Add Up? Clin J Sport Med. 13(3):192, May 2003.

2. Shephard RJ. Hard evidence for a Central Governor is still lacking! J Appl Physiol, in press 2008.

3. Noakes TD. Drinking guidelines for exercise: What evidence is there that athletes should drink “as much as tolerable”, to “replace the weight lost during exercise” or “ad libitum”? J Sports Sci 2007;25(7):781- 796.

4. Noakes TD, Sharwood K, Speedy D, et al. Three independent biological mechanisms cause exercise-associated hyponatraemia: evidence from 2,135 weighed competitive athletic performances. Proc Nat Acad Sci USA 2005;102(51):18550-18555.

5. Hew T, Almond C, Ayus C, et al. Consensus Statement of the 1st International Exercise-Associated Hyponatraemia Consensus Development Conference, Cape town, South Africa 2005. Clin J Sport Med 2005;15:208- 213.

6. Noakes TD, Martin DE. IMMDA advisory statement on guidelines for fluid replacement during marathon running. New Studies in Athletics 2002;17(1):15-24.

7. Noakes TD, Goodwin N, Rayner BL, Branken T, Taylor RK. Water intoxication: a possible complication during endurance exercise. Med Sci Sports Exerc. 1985 Jun;17(3):370-5.

8. Noakes TD. Lore of running. 4th ed. Champaign, Il: Human Kinetics, 2003.

9. Beltrami FG, Hew-Butler T, Noakes TD. Drinking policies and exercise-associated hyponatremia: is anyone still promoting overdrinking? Br J Sports Med 2008; 42:496-501.

10. Shephard RJ. Physiology and Biochemistry of Exercise. New York: Prager Publications, 1982.