Preventing Exertional Sickling Deaths

Introduction The Ig Nobel Prizes for 2013 were awarded recently at Harvard. Now in their 23rd year, the Ig Nobels celebrate the unusual, honor the imaginative, and spark interest in science and medicine. The awards make you laugh, then think. The Psychology Prize went to a study entitled “Beauty is in the eye of the beer holder” (2). This study shows that “beer goggles” can be imaginary. In Part 1, in a barroom in France, the more alcohol the volunteers drank, the more attractive they rated themselves. This is no surprise, just “beer goggles” trained on the self. Part 2 was more intriguing. In a balanced placebo design, 94 French men drank an alcoholic or a non-alcoholic beverage, half of each group believing they had consumed alcohol and half believing they had not. Then they gave a speech and rated how attractive, bright, original, and funny they thought they were. The speeches also were rated by 22 sober judges. Subjects who thought they had consumed alcohol (but got no alcohol) rated themselves higher on positive attributes than those who thought they had not consumed alcohol. In other words, if you just think you are drunk, you also think you are attractive. The judges, however, saw it differently. By their ratings, neither the real nor the imagined drunks were all that attractive. This study relates to placebo effects in sports and life. The second award introduces what I will cover here. The Ig Nobel for Probability went to a study entitled “Are cows more likely to lie down the longer they stand?” (16). Researchers in Scotland wanted to fathom how cows decide when to lie down and when to stand up. They put pedometers on 73 cows and studied 59,000 “lying behaviors.” They were half-right in their hypothesis. Sure enough, the longer a cow lies down, the sooner she will stand up. But unexpectedly, the reverse was not true: Once a cow stands up, you cannot easily predict when she will lie down again. Also some cows spend far more time standing than others. As researcher Bert Tolkamp said in his acceptance speech, “These cows just kept hanging around.” Some notions in sports medicine just keep hanging around. Let me explain. Exertional Sickling: American Society of Hematology Remains in Left Field In a noted study, Kark et al. (11) showed that, among black military recruits, sickle cell trait (SCT) increased the risk of exertional death 28-fold. Believing that sickling was secondary to heat stroke or major heat illness, Kark then led a decade-long military prevention study (1982 to 1991) that adjusted training and hydration to the heat. This study was never published, but Kark (10) wrote (in 2000) that during the study, based on prior rates of death, 15 deaths related to SCT would have been expected, but none occurred. This led the Army to stop screening recruits for SCT and to apply “universal precautions” for the heat. This is “The Army Way” to prevent death from “exercise collapse associated with SCT,” or ECAST (13). We know that SCT also can increase the risk of death for some athletes, notably in football conditioning. In data from the National Collegiate Athletic Association (NCAA), among black Division 1 football players, SCT increased the risk of exertional death 22-fold (8). To prevent ECAST deaths, the NCAA screens for SCT and tailors precautions to it. So “The NCAA Way” differs from “The Army Way.” Alas, the American Society of Hematology (ASH) disputes “The NCAA Way” and trumpets “The Army Way.” Their first essay said, “[The Army Way] has resulted in a marked decline in deaths ... in all soldiers ... including those with SCT” (15). I commented on their ill-informed stance (4). Unfortunately ASH has done it again. Their second essay, last May, characterizes their “response to a misguided NCAA policy” as a “paradigm” that “may improve public awareness and health.” They urge the NCAA to follow “The Army Way” as the only way. To her credit, the ASH writer admits to no expertise in this field (1). Indeed. ASH is unaware that “The Army Way” is not working. On SCT in soldiers and athletes, ASH remains deep in left field. The Army Way Is Not Working Recall, the Kark study “prevented” 15 ECAST deaths that decade (1982 to 1991). Soon after the study ended, however, the ECAST body count rose to prestudy levels and continues apace. I know of 17 military ECAST cases (14 fatal) in the past decade, eight reported in the medical literature and five in articles easy to find (3,6,7,14). Most collapses were during timed runs on the track, on days that were cool or only warm. Heat injury was a trigger in few or none, but sustained maximal intensity was a trigger in all. The evidence supports the conclusion that the military ECAST body count is the same “post-Kark” as it was “pre-Kark.” This despite fewer blacks (about 8% have SCT) in our active duty military in the past decade (about 17% of <1.5 million) than in the Kark study decade (about 20% of >2 million). In other words, “The Army Way” is not working. Nor is “The Air Force Way” working consistently. The Air Force screens for SCT, but evidently can lose track of it on occasion. We reported two Army recruits who died from ECAST (2008 and 2009), trying to run 2 miles fast enough to suit the Army; one died on her fifth try, on her son’s first birthday (7). Two in the Air Force experienced similar ECAST deaths (2011 and 2012), trying on cool days to run 1.5 miles as fast as they could. One ran “slowly and awkwardly” on the final lap, had a “controlled collapse” 80 yd from the finish, said he did not know what happened or why (his legs went out), “affirmed” he could finish, got up on his own, walked, jogged with a pained expression, and collapsed again, face first, 60 yd from the finish. The Air Force fitness personnel on site were not trained on ECAST. Within 10 min of his second collapse, he became unresponsive. He soon developed pulseless electrical activity, a typical arrhythmia from the “metabolic storm” (profound lactic acidosis, hyperkalemia, falling calcium) of fulminant rhabdomyolysis from exertional sickling. He was pronounced dead about 1 h after he began the run in good health. What to Do These ECAST deaths occur because maximal intensity sustained for several minutes can evoke the sickling foursome of 1) major hypoxemia, 2) profound lactic acidosis, 3) hyperthermia in working muscles, and 4) dehydration of red cells coursing through those muscles (5) — along with a sharp rise in circulating levels of epinephrine, which makes SCT red cells sticky (12). The result is exertional sickling, “logjamming” in the microvasculature of working muscles, and ischemic rhabdomyolysis, which can be explosive, evoking a metabolic storm that causes a lethal arrhythmia in a normal heart (5). At least Kark kept SCT awareness high during his prevention study in the military. We need to do the same in sports, especially football and basketball. It surely makes no sense to follow “The Army Way” in NCAA Division 1 football, for example. I agree with the team physicians who call for targeted precautions (9). In fact, “The NCAA Way” seems to be working. In NCAA Division 1 football conditioning, after 10 ECAST deaths in 10 years (2000 to 2010), with wider screening and tailored precautions for SCT, no ECAST death has occurred in nearly 4 years. We also need pediatricians to extend targeted precautions to some high school sports — and even youth league sports. In the past three seasons, for example, at least four (and maybe five) of the six black high school players who collapsed (nontrauma) on-field in summer football practice (and soon died) experienced ECAST. At this writing, in three of the four, medical examiners implicated exertional sickling in the deaths. Bottom line: We still have work to do. And ASH should bone up or clam up.