Can weight training cause elevated Lactate Dehydrogenase (LDH), Aspartate Aminotransferase (AST), and Alanine Aminotransferase (ALT) levels?

Weight Training Can Cause Elevated LDH, AST, and ALT Levels

Yes, intensive weight training can cause significant elevations in LDH (800), AST (400), and ALT (140) due to skeletal muscle injury rather than liver damage. 1, 2

Mechanism of Enzyme Elevation in Weight Training

• Intensive exercise, particularly weight lifting, can lead to acute elevations in liver enzymes due to muscle injury that can be mistaken for acute drug-induced liver injury (DILI) 1
• Muscle damage from weight training releases intracellular enzymes including:
  • Lactate Dehydrogenase (LDH)
  • Aspartate Aminotransferase (AST)
  • Alanine Aminotransferase (ALT) 2, 3
• While ALT is more liver-specific, it is still present in skeletal muscle and can be elevated with significant muscle damage 1, 4

Pattern of Enzyme Elevation in Exercise-Induced Muscle Injury

• AST/ALT ratio is typically >3 in acute muscle injury cases, distinguishing it from most liver pathologies 4
• In exercise-induced elevations, AST tends to decline faster than ALT, with the ratio approaching 1 after several days 4
• Olympic rowers and highly trained athletes demonstrate higher resting CPK and AST levels compared to untrained subjects 3
• Unilateral lower body resistance exercise causes higher skeletal muscle damage than bilateral exercises 5

Confirming Muscle Origin vs. Liver Origin

• Testing for blood levels of creatine phosphokinase (CK), aldolase, or other muscle-related enzymes can confirm the non-hepatic origin of enzyme elevations 1
• CK is markedly elevated in exercise-induced muscle damage and serves as the primary marker to differentiate muscle injury from liver injury 1, 6
• Ultra-endurance exercise can cause extreme enzyme elevations - one study of 246-km runners showed CK levels of 43,763 IU/L, LDH of 2,300 IU/L, AST of 1,182 IU/L, and ALT of 264 IU/L 6

Clinical Approach to Elevated Enzymes in Athletes

• When evaluating elevated liver enzymes in someone who exercises intensely:
  • Check CK levels to confirm muscle origin 1, 2
  • Consider timing of blood draw in relation to exercise (peak enzyme levels typically occur 5-60 minutes post-exercise) 3
  • Evaluate AST/ALT ratio (>3 suggests muscle injury in acute cases) 4
  • Assess for symptoms of liver disease versus muscle soreness 1

Differentiating from Other Causes

• Mild asymptomatic increases in ALT/AST (<3× ULN) without elevated bilirubin may be related to:
  • Nonalcoholic fatty liver disease (NAFLD)
  • Changes in diet
  • Vigorous exercise 1
• ALT elevation of ≥5× ULN is rare in NAFLD/NASH and usually should not be attributed to these conditions 1
• Alcoholic liver disease typically presents with AST:ALT ratio >2:1, different from the pattern seen in exercise 2, 1

Key Takeaway

• The specific enzyme elevations mentioned (LDH 800, AST 400, ALT 140) are consistent with the pattern seen in exercise-induced muscle damage rather than primary liver disease 6, 4
• These elevations are typically transient and resolve with rest 7
• If concerned about potential liver pathology, measuring CK levels can help confirm muscle origin of enzyme elevations 1, 2