Muscle Damage and Elevated Liver Enzymes

Did you know that heavy workouts can bump up your liver enzymes? Elevated levels may not be your liver, but rather your muscles talking. When you push hard in the gym, your muscle fibers can slightly tear, causing them to release these enzymes. This isn't a liver issue but a sign of your muscles repairing themselves after a tough workout. Let's further explore the connection between muscle damage and elevated liver enzymes.

How liver enzymes signal liver function

The liver is the main “chemist” in our body. It is the primary location for the conversion of one compound to another. Because of this, the liver can be thought of as the body’s detoxifier. If you have a liver, there is no need to “detox” through juice cleanses or lengthy fasts—your liver does that for you every day.

InsideTracker tests AST, ALT, GGT, and albumin to evaluate overall liver function. The first three are enzymes, and albumin is the main protein produced by the liver. Albumin is the primary transporter of hormones, drugs, and other compounds in our blood and helps control the pressure in our circulatory system.

Albumin levels outside of the normal range are rare for InsideTracker users.

Low levels are likely caused by severe liver damage, and high levels are typically due to dehydration or excessively high protein intake. Both high and low require medical attention.

Exercise and liver enzymes

The other three markers in our liver group are enzymes that initiate or support the detoxifying, energy-producing, and overall housekeeping reactions that keep our bodies functioning. They are:

• ALT: Alanine transaminase
• AST: Aspartate transaminase
• GGT: Gamma-glutamyl transpeptidase

These markers are found in large quantities in the liver and can be elevated in the blood when there is liver damage; however, they are also present in other tissues. While GGT is fairly specific to the liver, ALT, and AST are also found in significant quantities in skeletal muscles.

» Do you love a good workout? Find out how alcohol affects your athletic performance

ALT and AST levels post-exercise

ALT and AST levels can remain elevated after strenuous exercise for seven days or more. Some factors that can greatly impact these levels are:

• Intensity and duration: The more intense and prolonged the exercise, the higher the peak levels of ALT and AST, and the longer these levels remain elevated.
• Untrained vs. trained athletes: Untrained athletes typically experience larger and more prolonged increases in these enzymes than their trained counterparts.
• Effect of training: As athletes train, their work capacity increases. This allows them to handle greater training loads/volumes without a proportional increase in ALT, AST, and Creatine Kinase (CK) levels.
• Type of exercise: While resistance training generally causes greater muscle damage, significant damage can also occur in ultra-endurance events, especially those with significant changes in elevation.
• Susceptibility in sports: At InsideTracker, we've observed that trail runners, road cyclists, and mountain bikers are more prone to elevations in these enzyme levels.
• Creatine kinase: CK, an enzyme found in muscles, is another marker of muscle damage. It follows a similar pattern to AST and ALT after strenuous exercise.
• Protein intake: Eating or drinking protein after exercising helps repair muscle damage.



The general pattern of increases in aspartate transaminase (AST), alanine transaminase (ALT), and Creatine Kinase (CK) in response to muscle damage.

Monitoring muscle recovery through enzymes

Monitoring your levels of AST, ALT, and CK levels in training can help you determine if your muscles are recovering as they should be. Elevated levels of these enzymes after a workout might suggest more than a tough session. It could indicate that your muscles are taking longer to recover, raising concerns about overtraining, especially if you engage in intense workouts. Prolonged elevations in any of these markers may also mean that your training load is high.

The role of testosterone and cortisol in training

Testosterone and cortisol are vital for your training regimen. Here's a closer look:

• Testosterone: It's key for muscle repair in both men and women. If your testosterone starts dropping, it might mean your muscles aren't repairing as well as they should.
• Cortisol: This hormone increases when you're under a lot of training stress. It's your body's way of responding to increasingly intense or frequent workouts.
• The balance: Keeping these hormones in check is important. If testosterone drops, it could signal that your muscles struggle to recover properly from your workouts.

At the same time, as a response to the demanding frequency and intensity of workouts, cortisol uses muscle and fat to maintain energy levels.

» Discover 6 science-backed ways to naturally increase testosterone

Understanding hormone ratios and training impact

The Testosterone to Cortisol (T: C) and free Testosterone to Cortisol (fT: C) ratios are commonly used metrics to assess recovery and gauge if an athlete is pushing too hard. Athletes, particularly those involved in endurance or high-intensity sports, should be aware of these ratios as indicators of their training's effectiveness and sustainability.

Adapting training to biomarker feedback

Monitoring these enzymes and hormones helps athletes adapt their training effectively. It helps in identifying the fine line between optimal training and overtraining. Adequate recovery, including proper nutrition and rest, is essential to ensure these markers remain within a healthy range, aiding in sustainable athletic performance.

GGT and liver health

GGT (Gamma-glutamyl transpeptidase) stands apart from enzymes like AST and ALT.

Unlike AST and ALT, GGT isn't found in muscle tissue. Elevated GGT levels in your blood tests typically aren't linked to muscle damage from regular exercise routines.

Significance for liver health

GGT levels are a more specific indicator of general liver health. Factors such as alcohol consumption, usage of certain medications like Tylenol, or an overall unhealthy lifestyle can cause GGT levels to rise.

Connections with other biomarkers

An increase in GGT is often seen alongside other important health indicators when looking at InsideTracker's user population. While it's linked with lower levels of beneficial HDL cholesterol and vitamin D, it's also associated with higher levels of:

• Glucose
• LDL cholesterol
• hs-CRP (inflammation marker)
• Higher triglycerides

Observations from user data

Data show that individuals with elevated GGT levels often have imbalances in these other critical biomarkers, emphasizing the need for a comprehensive health and lifestyle management approach.

5 tips for keeping GGT levels within the optimal range

1. Drink alcohol in moderation (1 drink/day for women; 2 drinks/ day for men)
2. Use over-the-counter pain relief sparingly
3. Engage in moderate aerobic activity or HIIT
4. Maintain a healthy weight
5. Follow a healthy diet within your calorie needs that is high in fiber and low in saturated fat and added sugars



Keeping your liver in the game

Keeping an eye on liver enzymes like AST, ALT, and GGT is important, especially if you're into intense workouts or have a lifestyle that could affect your liver health. This knowledge helps you understand how your body responds to exercise and guides you in making smart choices for your health and training.

Sources:

[1] https://pubmed.ncbi.nlm.nih.gov/37025214/

[2] https://pubmed.ncbi.nlm.nih.gov/17764474/

[3] https://pubmed.ncbi.nlm.nih.gov/25117722/

[4] https://pubmed.ncbi.nlm.nih.gov/25948428/

[5] https://pubmed.ncbi.nlm.nih.gov/18354148/

[6] https://pubmed.ncbi.nlm.nih.gov/19067776/