Abnormal Lactate Levels Affect Motor Performance in Myotonic Dystrophy Type 1.

Area of Science:

• Exercise Physiology
• Metabolic Disorders
• Neuromuscular Diseases

Background:

• Myotonic Dystrophy type 1 (DM1) is a multisystemic genetic disorder.
• Patients frequently experience exercise intolerance due to fatigue, impacting rehabilitation adherence.
• Mitochondrial dysfunction and oxidative stress are implicated in DM1 pathophysiology.

Purpose of the Study:

• To evaluate the efficiency of oxidative metabolism in DM1 patients compared to healthy controls.
• To investigate exercise-induced changes in lactate levels as an indicator of metabolic function.

Main Methods:

• 18 DM1 patients and 15 healthy controls underwent a submaximal incremental exercise test on a treadmill.
• Blood lactate levels were measured at rest and at 5, 10, and 30 minutes post-exercise.
• Exercise performance (steps completed) was recorded.

Main Results:

• DM1 patients completed significantly fewer exercise steps (mean 9) compared to controls.
• Resting lactate levels were similar, but post-exercise lactate was significantly higher in DM1 patients at all recovery points.
• These findings indicate an early shift to anaerobic metabolism during exercise in DM1.

Conclusions:

• DM1 patients demonstrate impaired oxidative metabolism and early exercise fatigue.
• Elevated post-exercise lactate suggests reduced oxidative capacity and impaired lactate clearance.
• Aerobic training may improve oxidative capacity and lactate removal, aiding DM1 rehabilitation.