The Impact of Weight Training on High 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. 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.

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. 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. Intensive muscular exercise, e.g., weightlifting, should also be considered as a cause of asymptomatic elevations of liver function tests in daily clinical practice.

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. This is especially important for men on testosterone replacement therapy (TRT) who usually workout, 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.


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