Really, Amy? You are asking me the color of my pee? Well I’m not suggesting you go examine it right now or report the color to me, however urine color can be an indicator of a condition that afflicts endurance athletes called acute exercise-induced rhabdomyolysis (AER). The media has once again brought this condition to the forefront with the recent hospitalization of several members of the Oregon Ducks football team.
AER is an acute, serious and potentially life threatening condition for which the hallmark symptom is cola colored urine. AER occurs when skeletal muscle is severely damaged through injury or profound overexertion.
AER can cause damage to the kidneys, liver and long term nerve and muscle damage. I discovered in my research of the topic, that the incidence of this condition in endurance athletes is not clear .
Acute kidney failure may be less likely in AER compared to other causes of rhabdomyolysis . Therefore, it is conceivable that some endurance athletes are not diagnosed and treated, yet suffer from other long-term complications such as damage to nerves and muscles.
The signs and symptoms of AER are listed below . Keep in mind that not all athletes with AER exhibit the following symptoms and these symptoms can also be caused by other conditions.
- Dark brown urine (cola colored)
- Muscle pain (not normal delayed onset muscle soreness)
- Generalized weakness
As with many issues afflicting the endurance athlete, the cause of AER is a combination of "the ‘perfect storm’ where there are several [contributing] factors (heat stress, dehydration, [muscle exertion], non-steroidal anti-inflammatory [e.g. Alleve, Ibuprofen] or other drug/analgesic use, and viral/bacterial infection).” 
The most common cause of AER is simply, "too much.”
- Too much too soon (e.g. returning to sport or starting a new form of exercise without a gradual introduction).
- Too much eccentric contraction of the same muscle group (e.g. high reps of heavy weight jump squats).
- Too much heat (running long distances or racing in high temperatures without proper acclimatization).
Other significant contributors to AER include high exertion in concert with:
- Certain medications namely statins and NSAIDs (Alleve, Ibuprofen)
- Hyponatremia (overhydration - too little sodium)
When you look at the list of causes, it is sobering right? How many triathlons and marathons have you raced under the "perfect storm" of extreme heat before being acclimated, dehydrated, taking pain killers (even though your coach told you not to) and/or coming off an injury or illness?
In one case study, four ultra distance runners in two separate years were tested after they ran the 95-mile off-road West Highland Way Race . All tested positive for severe cases of AER. Each of them raced in at least half of the "perfect storm" conditions.
The take-away from all this? Train smart with a solid training plan and expert coaching, do not take NSAIDS before or during a race, avoid racing when sick or after a recent illness, and acclimate to hot weather running or modify if you find yourself in those conditions unprepared.
As always, listen to your body. Be aware of contributors to AER and it’s symptoms. If you find yourself with cola colored urine after extreme exertion, seek immediate medical attention; AER can be reversed if treated quickly. The long-term consequences when not treated properly could be severe and once an athlete has suffered from AER, they are more susceptible to recurrence.
 Brudvig T, Fitzgerald P. Identification of Signs and Symptoms of Acute Exertional Rhabdomyolysis in Athletes: A Guide for the Practitioner. Strength and Conditioning Journal. 2007 Feb;29 (1):10-14
 Sinert S, Kohl L, Rainone T, Scalea T. Exercise-Induced Rhabdomyolysis. Annals of Emergency Medicine. 1994 June;23(6):1301–1306.
 Clarkson P. Exerctional Rhabdomyolysis and Acute Renal Failure in Marathon Runners. Sports Medicine. 2007 April;37(4):361-363.
 Ellis C, Cuthill J, Hew-Butler T, George S, Mitchell R. Exercise-Associated Hyponatremia with Rhabdomyolysis During Endurance Exercise. The Physician and Sportsmedicine Volume. 2009 April;7(1):126-131.