Weight Training Can Increase Liver Enzymes

Author: Nelson Vergel

High AST and ALT in Bodybuilding: How Weight Training Can Affect Liver Function

Understanding Liver Function Tests

Liver function tests (LFTs) are essential tools in assessing an individual’s overall health. These tests evaluate the liver’s ability to perform its vital functions, such as detoxification, metabolism, and the production of essential proteins. By measuring specific enzymes and proteins in the blood, LFTs can detect liver damage or disease, allowing for early intervention and treatment. In the context of exercise and muscle damage, LFTs are particularly valuable as they help differentiate between liver damage and muscle damage, which can both cause elevated liver enzymes.

Importance of Liver Function Tests in Monitoring Health

Liver function tests play a crucial role in monitoring an individual’s health. They provide insights into the liver’s performance and can detect early signs of liver damage or disease. Elevated liver enzymes, such as ALT and AST, can indicate liver inflammation or damage. However, these enzymes can also be released into the bloodstream due to muscle damage from strenuous exercise. By conducting LFTs, healthcare professionals can determine whether elevated liver enzymes are due to liver damage or muscle damage, ensuring accurate diagnosis and appropriate treatment.

What Liver Function Tests Measure

Liver function tests measure the levels of various enzymes and proteins produced by the liver. The most common LFTs include:

Alanine transaminase (ALT): An enzyme that helps convert proteins into energy for liver cells. Elevated levels can indicate liver damage.
Aspartate transaminase (AST): An enzyme found in the liver and other tissues, such as the heart and muscles. Elevated levels can indicate liver or muscle damage.
Alkaline phosphatase (ALP): An enzyme related to the bile ducts; often increased when they are blocked or inflamed.
Gamma-glutamyl transferase (GGT): An enzyme involved in the metabolism of drugs and toxins. Elevated levels can indicate liver or bile duct damage.
Bilirubin: A waste product from the breakdown of red blood cells. Elevated levels can indicate liver dysfunction or bile duct problems.

These tests help identify liver damage or disease and monitor the effectiveness of treatment, providing a comprehensive picture of liver health.

Normal Ranges for Liver Enzymes

The normal ranges for liver enzymes can vary slightly depending on the laboratory and the individual’s age, sex, and other factors. Generally, the normal ranges are:

ALT: 0-40 U/L
AST: 0-40 U/L
ALP: 30-120 U/L
GGT: 0-60 U/L
Bilirubin: 0.1-1.2 mg/dL

It’s important to note that these ranges can vary, and a healthcare professional should interpret the results in the context of the individual’s overall health and medical history. Understanding these normal ranges is crucial for accurately interpreting liver function tests and diagnosing potential liver issues.

High AST and ALT in Bodybuilding: How Weight Training Can Affect Liver Function

Understanding Liver Function Tests

Importance of Liver Function Tests in Monitoring Health

What Liver Function Tests Measure

Liver function tests measure the levels of various enzymes and proteins produced by the liver. The most common LFTs include:

Alanine transaminase (ALT): An enzyme that helps convert proteins into energy for liver cells. Elevated levels can indicate liver damage.
Aspartate transaminase (AST): An enzyme found in the liver and other tissues, such as the heart and muscles. Elevated levels can indicate liver or muscle damage.
Alkaline phosphatase (ALP): An enzyme related to the bile ducts; often increased when they are blocked or inflamed.
Gamma-glutamyl transferase (GGT): An enzyme involved in the metabolism of drugs and toxins. Elevated levels can indicate liver or bile duct damage.
Bilirubin: A waste product from the breakdown of red blood cells. Elevated levels can indicate liver dysfunction or bile duct problems.

These tests help identify liver damage or disease and monitor the effectiveness of treatment, providing a comprehensive picture of liver health.

Normal Ranges for Liver Enzymes

The normal ranges for liver enzymes can vary slightly depending on the laboratory and the individual’s age, sex, and other factors. Generally, the normal ranges are:

ALT: 0-40 U/L
AST: 0-40 U/L
ALP: 30-120 U/L
GGT: 0-60 U/L
Bilirubin: 0.1-1.2 mg/dL

The Impact of Weight Training on Elevated Liver Enzymes

If you have high levels of transaminases, especially alanine transaminase (ALT) and aspartate transaminase (AST), it could mean that your liver is damaged or even has cancer, or it could mean that you are hitting the gym hard. Vigorous exercise, such as intense weightlifting, can also cause a temporary increase in liver enzyme levels. The liver has transaminases, such as ALT levels, to synthesize and break down amino acids and to convert energy storage molecules. The concentrations of these transaminases in the serum (the non-cellular portion of blood) are normally low. However, if the liver is damaged, the liver cell (hepatocyte) membrane becomes more permeable, and some of the enzymes leak out into the blood circulation. A blood test can show elevated liver enzymes. The blood test checks for raised levels of AST and ALT, which are enzymes that the liver releases when it becomes inflamed or damaged. If a doctor finds that a person has raised AST or ALT levels, they are likely to carry out further tests to determine the underlying cause of liver damage, such as acute viral hepatitis, chronic viral hepatitis, or cirrhosis of the liver. Other medical conditions can increase liver enzymes, like hepatitis B or C and a condition that runs in families called hemochromatosis. Chronic liver disease, such as non-alcoholic steatohepatitis (NASH), can also lead to elevated liver enzymes.

Liver Enzyme Tests and Exercise

The two transaminases commonly measured as part of a liver function panel are alanine transaminase (ALT) and aspartate transaminase (AST). These levels were previously called serum glutamate-pyruvate transaminase (SGPT) and serum glutamate-oxaloacetate transaminase (SGOT). Elevated levels are sensitive to liver injury, meaning that they are likely to be present if there is an injury. However, they may also be elevated in other conditions such as thyroid disorders, celiac disease, and muscle disorders. Elevated liver enzymes can also be a result of drug-induced liver injury, which requires careful interpretation of liver function tests to distinguish from exercise-induced elevations. Additionally, several studies have described enzyme elevations in response to running, whereas only a few have dealt with the effects of weight training. The effects of muscular exercise on clinical chemistry parameters may also vary depending on gender and the fitness level of the individual. But before 2008, no research looked at how weightlifting might affect lab tests that are often used to check how well the liver is working, how long that effect might last, or whether people with weightlifting had yellow eyes or skin, which is a common sign of jaundice. The gamma-glutamyltransferase (GGT) test is another liver enzyme test that can provide valuable insights into liver and bile duct damage.

The Effect of Weight Training on Liver Enzyme Tests: Study

The Swedish study, which was published in the February 2008 issue of the British Journal of Pharmacology, looked at what happened to liver enzymes in healthy men who did heavy weightlifting just once. The men were not used to doing heavy weightlifting regularly. A second goal was to look into what effect a single bout of intense muscle exercise (weightlifting) had on creatine kinase (CK) and myoglobin, two clinical chemistry markers that show muscle damage.

Fifteen healthy men, used to moderate physical activity, not including weightlifting, performed a 1-hour-long weight training program. The following clinical chemistry parameters were measured in the blood: aspartate aminotransferase (AST), alanine aminotransferase (ALT), lactate dehydrogenase (LD), gamma-glutamyl transferase (γGT), alkaline phosphatase (ALP), bilirubin, creatine kinase (CK), and myoglobin. These tests were done several times during the first week after exercise and again 10–12 days later.

Five out of eight studied clinical chemistry parameters (AST, ALT, LD, CK, and myoglobin) increased significantly after exercise (P < 0.01) and remained increased for at least 7 days post-exercise. Bilirubin, γGT, and ALP remained within the normal range.

The liver function parameters, AST and ALT, were significantly increased for at least 7 days after the exercise. In addition, LD and, in particular, CK and myoglobin showed highly elevated levels. These results show how important it is to limit weightlifting before and during clinical studies so that wrong assumptions are not made about how study drugs might hurt the liver. This is particularly important in patients with pre-existing liver disease, where elevated enzyme levels could be misinterpreted. Intensive muscular exercise, e.g., weightlifting, should also be considered as a cause of asymptomatic elevations of liver function tests in daily clinical practice.

Muscle Damage and Liver Enzymes

Exercise-Induced Muscle Damage and Liver Enzyme Release

Exercise-induced muscle damage can lead to the release of liver enzymes, such as AST and ALT, into the bloodstream. This occurs because muscle tissue contains these enzymes, and when muscle damage happens, they are released into the blood. Strenuous exercise, like weightlifting, can cause significant muscle damage, leading to a temporary increase in liver enzymes. This increase can sometimes be misinterpreted as liver damage, but it usually resolves on its own once the muscle damage heals.

It’s essential to recognize that muscle damage can also result from other factors, such as muscle conditions, medication use, or other medical conditions. A healthcare professional should evaluate the individual’s overall health and medical history to determine the cause of elevated liver enzymes.

In the context of exercise, it’s important to consider the type and intensity of the activity, as well as the individual’s fitness level and medical history. High-intensity exercises, such as weightlifting, can cause more significant muscle damage compared to low-intensity activities like yoga. Understanding this distinction helps in accurately interpreting liver function tests and avoiding misdiagnosis.

In conclusion, liver function tests are vital in monitoring an individual’s overall health. Understanding the normal ranges for liver enzymes is crucial for interpreting the results accurately. Exercise-induced muscle damage can lead to the release of liver enzymes, but this increase is usually temporary and resolves once the muscle damage heals. A healthcare professional should evaluate the individual’s overall health and medical history to determine the cause of elevated liver enzymes, ensuring accurate diagnosis and appropriate treatment.

Doctors Need to Know that Exercise Can Increase Liver Enzymes

Liver function tests are significantly increased for at least 7 days after weight training among men used to moderate physical activity but not used to performing weight training on a regular basis. In line with these findings and to rule out any possible exercise-related effects on liver function tests, it is important to limit weight training for at least one week before the start of clinical trials. The study also shows how important it is to think about weight training and probably other types of intense muscle training as possible causes of liver function tests that are elevated without any symptoms in everyday clinical practice. This will reduce the risk of erroneously attributing changes in liver function tests to a drug effect. Recognizing liver enzyme alteration due to exercise is crucial for accurate diagnosis and treatment. This is especially important for men on testosterone replacement therapy (TRT) who usually work out, and that may have led physicians to wrongly assume that TRT is causing liver abnormalities. Additionally, individuals with high blood pressure should also be cautious when engaging in weight training to avoid any potential impact on liver function. People can work with their doctor to treat NAFLD with weight loss. The doctor may advise a person to make lifestyle changes to lose weight, such as exercising more, eating a healthy, balanced diet, and trying to burn more calories than they consume. Speaking with a nutritionist or even a personal trainer can help someone stay on track with their weight-loss plan. Alcohol consumption can exacerbate the effects of weight training on liver function and should be avoided to maintain liver health.

Reference:

Br J Clin Pharmacol. 2008 Feb; 65(2): 253–259.

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