Have you ever wondered what is happening in your body after you complete that Ironman Triathlon or that Ultra Run of 50 or 100 miles? As these events become more popular, especially in the masters competition. These events bring tremendous amounts of joy and a sense of accomplishment. But most athletes don’t have any idea about what such an event does to a body past muscle soreness.


Example Number One – Liver Function Tests

This is a masters female Ironman Triathlete who is good health and takes no medications. Her preparation for the event was uneventful and she completed the Ironman in about 14 hours. She experienced severe cramping near the end of the run, but nothing out of the ordinary and she was able to reach the finish. After the race she experienced the normal post exercise soreness. She had a normal dinner and the next day she felt fine. She performed her labs some days before the event, and again retested 3 days after the event. The results were pretty remarkable.

Before the race, her labs were completely normal. After the race, her liver enzymes were highly abnormal. In fact, they were so high, that if a doctor had looked only at the labs, he/she would think of a horrible liver disease.

Pre race metabolic panel showing the LFT's
Post race metabolic panel showing the elevated LFT's

The liver enzymes pre race are clearly normal, suggesting everything is status quo. The LFT’s after the Ironman are very high. In fact, it is rare to see them this high. When Liver Function Enzymes  (LFT) increase into the thousands, that signifies that many liver cells were damaged and released their enzymes into the blood stream.  This is why when we measure the blood, the LFT’s are elevated. In medical speak, we call this phenomenon of elevated LFT’s, or Transaminitis.

In medicine, we develop something called a differential diagnosis. The differential diagnosis for elevated LFT’s in the 1000’s is ischemic hepatitis, acute viral hepatitis, drug or toxin induced liver injury (usually from Tylenol).  Since this athlete had a rapid fall in LFT’s, the most likely diagnosis is ischemic hepatitis. This makes sense because during exercise, especially long endurance type exercise, blood is diverted to other areas.

Keep in mind she never felt bad, or abnormal and she recovered just fine after the event. A literature search revealed a couple of studies on the effects of prolonged exercise on blood laboratory markers in humans.

How Prolonged Exercise Affects your Liver

Alanine aminotransferase (ALA) and aspartate aminotransferase (AST) are specific markers for hepatic injury and are often increased after exercise. Unlike other laboratory values, liver enzymes tend to remain elevated for some days after prolonged exercise. Potential hepatic cell injury after prolonged exercise is related to damage of muscle cells, but to a minor degree. It is thought that the increase in liver enzymes are actual damage to the liver cells from the stress of prolonged exercise. This liver injury is suggested to be from direct hepatic cell injury and obstruction of the biliary system. This probably happened as a the damage to the liver is directly correlated to the workload of the exercise. Certainly, factors such as hydration, core temperature, baseline liver health, and more all play a role in how much the liver enzymes will be affected post exercise.

It is well known that prolonged exercise can result in electrolyte abnormalities, rhabdomyolysis (destruction of muscle cells), kidney injury and hepatic (liver) injury. Even acute myocardial infarction and sudden cardiac death has been reported in endurance athletes. Beside the effects of marathon running on the heart and fluid homeostasis, the degree of potential organ damages, that is of the liver and kidney subsequent to rhabdomyolysis, has been rarely studied and we just don’t know a lot about what is really happening. Keep in mind this is an isolated case, and does not represent the general population. It does show the potential of what can happen to the liver during an Ironman Triathlon.