Jan 29, 2015
Too Much Too Soon: Examining the threat of exertional rhabdomyolysis
By Dr. Stan Reents

The”no pain, no gain” concept is ingrained in athletic culture, but a serious condition called exertional rhabdomyolysis should have athletes and coaches on guard.

strength and conditioningIn mid-August, the McMinville (Ore.) High School football team was the center of a flurry of national news reports. It would have been nice if the media coverage was about the team’s upcoming season or a star player. But instead, reports said many athletes on the squad had been stricken with some sort of mysterious illness.

According to an Oregon Public Health Division preliminary report, over the course of three days, about half of the 43 players who attended a training camp before the start of official practices went to a local hospital complaining of severe muscle pain in their arms. At first, it was assumed the athletes had misused a creatine supplement, but days later a different theory emerged: the players were suffering from exertional (or “exercise-induced”) rhabdomyolysis (ER).

According to the report, the athletes had undergone a short, repetitive triceps workout — the main cause for the condition. Other factors that likely contributed included a hot environment — one media outlet stated the workout was held indoors in a 100-plus degree room — and undetected dehydration. Of the 22 players with exertional rhabdomyolysis symptoms, three underwent emergency surgery for compartment syndrome, 12 were hospitalized for treatment of ER, and all made a full recovery.

In a nutshell, ER is the extensive breakdown of skeletal muscle that can lead to kidney failure and even death. During any challenging workout, muscle damage is expected — we stress our muscles, they break down, then build back up stronger than they were to meet the demands of the stress placed on them. But when that process occurs at a massive rate, some bodies can’t always handle the processes necessary for recovery.

While considered to be uncommon, people of any age or fitness level can be stricken with ER. The condition most commonly occurs in “crushing” injuries, such as those experienced in earthquakes or car accidents, where muscles are severely damaged by impact, but athletes can and do fall victim to ER. Fortunately, with early and proper treatment, athletes who develop ER can make a complete recovery.

Exertional rhabdomyolysis explained

When muscle cells break down, the damaged contents leak out and are deposited into the bloodstream. Two of the products released are the enzyme creatine kinase (CK) and the muscle protein myoglobin. The kidneys can only handle a certain amount of protein, so when too much myoglobin reaches the kidneys, it can result in kidney damage and even complete failure.

The elevated levels of CK are what help physicians diagnose ER. While the normal range of CK levels is 60 to 320 units per liter (U/L) of blood, in severe cases of exertional rhabdomyolysis, CK levels can reach above 300,000 U/L. It’s important to note, however, that elevated CK levels don’t always mean the athlete is experiencing ER. For example, it rarely occurs in trained runners after a marathon, even though their post-race CK levels exceed 3,000 U/L.

There is a race in Greece called the Spartathlon that requires running from Athens to Sparta (152 miles!) in under 36 hours. Within 15 minutes after completing the event, participants’ CK levels are sky high, though very few require medical attention during or after the race. This phenomenon is called asymptomatic rhabdomyolysis. Because the runners who participate in the Spartathlon, and ultra marathoners everywhere, train their bodies to become accustomed to this sort of prolonged demanding activity, their fitness levels are so elite that less muscle trauma occurs and ER symptoms do not occur.

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ER follows a progression. Within hours of muscle breakdown, CK and myoglobin levels become elevated. Though CK levels can only be determined with a blood test, when a person has too much myoglobin in their bloodstream, their urine turns a dark brown color — a symptom commonly referred to as “Coca-Cola urine.” Within 24 to 48 hours of the workout, ER sufferers experience severe, even incapacitating muscle pain, swelling, and profound weakness in the overworked area of the body. For example, if an athlete were to perform an intense biceps workout and it triggered ER, the athlete would feel pain only in their arms.

If there’s any sign of ER, the athlete must seek medical help immediately — at an urgent care facility or an emergency room. IV fluids are often necessary, as rehydration is an important component for recovery. If treatment is not sought, kidney damage can result several days later.

ER symptoms generally last a couple of days, after which muscle pain subsides and CK levels return to normal. But in severe cases, there may be irreversible muscle damage. If this happens, an athlete can lose muscle strength and range of motion that may never return. ER has also been shown to cause compartment syndrome, a painful condition that includes intense pressure on nerves, blood vessels, and muscles in an enclosed area (compartment) of the body and generally requires surgery to relieve pressure.

What causes exertional rhabdomyolysis?

As implied by its name, exertion is the most important risk factor for ER. For someone with a low activity level, all it may take is a challenging workout session for symptoms to appear. And even in a well-conditioned athlete, higher than normal stress on the muscles can put them at risk for ER.

But coaches conduct tough workouts all the time. How can someone know how much is too much? There is no simple answer, but the key is if the athlete’s body is accustomed to a particular workout. In published cases, the following workout examples led to ER:

  • A 22-year-old college senior whose exercise routine included running three to five miles per day and lifting weights five days per week developed ER after her fitness trainer increased her weight lifting load and reps in one session. The trainer pushed her to continue the workout and had to assist her from one exercise machine to the next as her legs shook noticeably during the session. Forty-eight hours later, the emergency room found her CK value was 234,000 U/L.
  • A 29-year-old man developed ER after starting a new abdominal workout: 30 to 40 sit-ups per day for five consecutive days.
  • A former Navy sailor and wrestler was put through a three-round workout of dumbbell thrusters, air squats, and burpees at a gym and claims the resulting severe bout of ER left him permanently disabled. He sued the gym and was awarded a settlement in 2008.

The type of exercise may be another risk factor. Eccentric exercises, in which the muscle lengthens, have been shown to cause more muscle injuries than concentric exercises, in which the muscle contracts. The more muscle damage there is, the higher the risk of ER. In one case, a 40-year-old male developed ER in his biceps after doing several sets of negative curls — in which a spotter assists in lifting a barbell up to the ready position and then the subject lowers the barbell on his own until his arms are in an extended position. Roughly 18 hours after doing negative curls, this athlete experienced severe biceps pain and could not fully extend his arms.

Some people may be at higher risk due to genetic predisposition. For example, people with carnitine palmitoyltransferase (CPT) II deficiency, an inherited metabolic disorder, have a higher likelihood of developing ER. This was the case for a 19-year-old college freshman who experienced two episodes of ER while playing competitive ultimate Frisbee.

The first episode occurred following a five-hour tournament (her actual playing time was estimated to be three hours) when she developed severe muscle soreness. The athlete was unable to straighten her elbows and knees and had difficulty standing because of soreness in her back. Though her urine turned a brownish color, she did not seek medical attention.

After muscle soreness resolved in three days, she continued her normal activity level. But two weeks later, she had a relapse when she participated in a two-hour Frisbee scrimmage followed by a two-hour karate class. Shortly thereafter, she experienced severe muscle cramping and this time sought medical attention. The following day, her CK levels peaked at 59,000 U/L. Although the athlete had no history of ER and had been active all her life, it was subsequently determined that she had CPT II deficiency.

Hot weather and dehydration may also contribute to an athlete developing ER. Though there is no scientific evidence to support that a hot environment contributes to the onset of ER, in many documented cases, the workout room temperature or outside humidity has been unusually high.

It’s possible that certain drugs could put someone at higher risk for ER. Published case reports point to two categories of prescription drugs: phenothiazine-type neuroleptics (antipsychotics) and statins (cholesterol-lowering drugs). Anabolic steroids have also been blamed for the development of ER in bodybuilders, though this is not proven. Unfortunately, it’s not possible to predict which patients taking these drugs will develop ER, but it’s important to be aware of the increased risk.

Ephedra, its closely-related replacement synephrine, and creatine have made the list as possible contributors, too. In one case, a healthy 21-year-old soldier developed ER after a physical fitness test, and admitted to taking two tablets of an herbal supplement containing ephedra daily for a month leading up to the test. The evidence that says creatine supplementation could be at fault for ER is far less substantial. Still, many researchers hypothesize that it could contribute to increased risk.

An exertional rhabdomyolysis prevention program

The guidelines for preventing ER are very similar to general advice for anyone beginning a new workout routine. Because the main culprit is doing too much at once, gradually moving into a workout program or a gradual increase to an already-instituted workout program is best. For athletes who take the summer off, resuming training with intense two-a-day preseason sessions can be dangerous. Coaches should encourage their athletes to stay active when school is out of session.

Keeping athletes’ core temperatures as close to normal as possible will also help. Hydration plays a key role in keeping core temperatures under control and allowing an athlete’s body to perform physical tasks in a healthy way. Wearing breathable clothing and not performing intense workouts in extreme heat are other suggestions.

And although research is lacking regarding ephedra’s link to ER, it would be best to steer clear of any supplements with ephedra in them. Ephedra can cause problems because it may increase core body temperature and/or may allow the athlete to train harder than is safe.

If it’s not already a ritual for them, athletes should consider adding a post-workout recovery beverage to their routine. Several recent studies have shown that post-exercise CK levels are lower in athletes who regularly consume a sports drink that contains protein.

The human body talks to us all the time. When a muscle group is shaking or no longer able to contract, that’s a major signal to stop activity. In fact, at this point, muscle damage may have already occurred.

The concept of “no pain, no gain” should be discouraged. Sport coaches, strength coaches, fitness trainers, and athletes all need to better understand that training gains can still be achieved by “moderately” challenging the muscle group. Pushing the athlete past his or her limits isn’t always the best approach and certainly isn’t worth the risk.

Stan Reents, PharmD, is the Editor in Chief of AthleteInMe.com and author of Sport and Exercise Pharmacology. A member of the American College of Sports Medicine, he holds Personal Trainer and Lifestyle Counselor certifications from the American Council on Exercise and is a United States Tennis Association certified coach.

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