Weekend warriors are flocking to military-style obstacle races, but recent events question the safety of this fast-growing and poorly regulated enterprise. Meanwhile an alarming number of deaths continues to plague the swim leg of triathlons. And even real warriors can face undue problems when their leaders decide to build Rome in a day. Let me explain.
Outdoor obstacle races are all the rage. Modeled in part after military-style obstacle courses, and with colorful names like Tough Mudder, Warrior Dash, and Spartan Race, these untimed events offer a chance to overcome a tough physical challenge — to earn a badge of courage — and to bond with friends in teamwork and rowdy fun. Obstacles can include wall climbs, monkey bars, fire jumps, two-story slides into rocky ravines, a belly crawl through mud and under barbed wire, a run through water while dodging dangling electrical wires, and a 15-ft drop into a pool of cold, deep, murky water. It was this last obstacle, called Walk the Plank, that led to the drowning death of Avishek Sengupta, 28, in a Tough Mudder event in West Virginia in April 2013 (9,14,15).
Some call for a governing body and better safety standards for this fast-growing industry, which this year expects up to 1 million participants. They point to a few other deaths, including two from heat stroke, and to many injuries, including paralysis after falling from a wall or diving headfirst into a shallow pond or mud pit. The Tough Mudder events that led to the drowning death in West Virginia sent 20 patients to one hospital. Problems included heart attacks, electrical shock, hypothermia, and a variety of orthopedic and head injuries (9,14,15).
A similar spate of injuries occurred on a Tough Mudder weekend in Pennsylvania in June 2013, when 38 patients were seen in the same hospital emergency room. Problems included heat injuries, syncope, rhabdomyolysis, seizures, asthma, broken bones, dislocations, and other orthopedic injuries. One young man experienced a stroke during the event, and four patients were hurt by electrical shocks to the head, chest, or back, including one with electrical burn marks and one who fell when shocked in the head and landed face first in hard dirt (6). The diagnoses of myocarditis and possible pericarditis from electrical shock (in two of these patients) seem implausible, but they bring to mind the hot debate on how often TASER causes fatal ventricular fibrillation and how to prevent this tragedy (8,16). At least the robust TASER debate has vital social merit, because the TASER also saves lives. In contrast, the Electroshock Therapy obstacle in the Tough Mudder course is just a dumb idea that should be discarded.
The Walk the Plank death of Avishek Sengupta was tragic, and Tough Mudder safety measures are under attack (9,14,15), but this may be the only drowning death in Tough Mudder events. In contrast, the wave of swim deaths in triathlons is alarming. In a 7-year span from 2007 to late 2013, at least 52 triathletes died in action, 44 (38 men, 6 women) during or right after the swim (5). In 2011, I covered the mystery of swimming deaths in athletes (3). I mentioned the study of 13 triathlon swim deaths from 2006 to 2008. In that study, evidence for clinically important heart disease was minimal. Drowning was the declared cause of death in each case (7). I discussed ways to die in the swim, and keyed on dense, mass starts in deep, choppy water. It seems to me that such triathlon starts can cause chaos, trauma, panic, and drowning. In that setting, strong swimmers can overtake, bang into, kick in the head, and even swim over weak swimmers, who may then panic, hyperventilate, inhale water, and drown (3).
Heart attacks account for some triathlon swim deaths. More than half of the 44 who died were men in their 40s and 50s, and some had cardiac atherosclerosis or prior paroxysmal arrhythmias. Race anxiety, tight wetsuits, no warm-up, heroic effort, and cold water may combine to trigger arrhythmias. Inherited cardiac channelopathies also may contribute. In a recent autopsy series, postmortem genetic testing found that nearly 30% of 28 victims of unexplained swimming-related drowning had mutations for long QT syndrome or catecholaminergic polymorphic ventricular tachycardia (13). Swimming is well-known to trigger fatal arrhythmias in both of these conditions.
Panic drowning, however, with no underlying heart disease, seems to be the cause of some or many triathlon swim deaths. Some race directors may favor victim blaming over fact finding, but safety measures are increasing. These include shortening or canceling the swim if the water is too choppy or cold; encouraging preswim water warm-ups; eliminating mass starts; adding more lifeguards, spotters, and boats; and placing more marker buoys and even recovery docks along the course. We can hope that these and other safety and educational precautions will stem the tide of triathlon swim deaths.
Team Rhabdomyolysis in the Navy
Recently I covered pearls from team rhabdomyolysis in college and high school sports (2). Now I report “team rhabdomyolysis” in the U.S. Navy, proving the following Army adage: “The drill sergeant is not your friend.”
At a base in Hawaii in August 2013, during chief-selectee training, 12 sailors were hospitalized for exertional rhabdomyolysis (ER). One fine day, their leaders decided to push them much harder, to mimic a drill favored by an honored Navy SEAL who had been killed in combat in Afghanistan. So they ordered a group of 20 sailors to run from one training site to another, to do as many pull-ups as possible in repeat bouts to exhaustion over 20 min, followed by 200 push-ups in 15 min, followed by 300 squats in 15 min. These sailors had never done this much in physical training, or any pull-ups at all. No one quit, although some threw up. The next day, however, some had swollen, painful arms from ER, and 12 were hospitalized for up to 3 d (4).
This “team outbreak” of ER in the Navy parallels those in sports: By far, the most common cause of ER in healthy athletes or warfighters is novel overexertion enforced by a coach or drill instructor. Live and learn, even in the Navy.
A final pearl is on creatine kinase (CK) levels in ER. In gauging return to duty, the U.S. military stratifies ER cases into low or high risk for recurrence. One article lists 10 high-risk factors, including peak CK >100,000 U·L−1 (10). This cutoff is conservative, but is arbitrary, not evidence based. In the absence of heat stroke or sickle cell trait, ER from novel overexertion in healthy athletes or warfighters is almost never fatal, and peak CK >100,000 U·L−1 is common in ER that proves benign.
For example, of the 13 Hawkeye football players hospitalized for ER in January 2011, CK values were published on 10 (12). A total of 9 were >100,000, 4 of them >200,000, 1 of them >300,000 U·L−1, yet the clinical courses were fairly benign. And I have in my files more than 50 cases of ER from novel overexertion in which CK was >100,000 U·L−1 (many >200,000 or 300,000 U·L−1), yet the clinical courses were benign. Two young men who underwent extreme novel weightlifting had ER with CK >1 million U·L−1 yet benign courses (1,11). All this proves yet again, that medicine is a humbling profession.
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