Overtraining can make your muscles worse at using sugar for energy, so they store less fuel and produce more lactic acid, making you tire faster.
Evidence from Studies
No evidence studies found yet.
What Would Prove This
Per GRADE and EBM methodology, here is what ideal scientific evidence would look like to definitively prove or disprove this claim, ordered from strongest to weakest.
Provide pooled estimates of insulin sensitivity and GLUT4 expression differences in OTS.
A meta-analysis of 10+ studies using hyperinsulinemic-euglycemic clamps and muscle biopsies to assess insulin sensitivity and GLUT4 expression in athletes with OTS versus controls, with at least 200 participants.
Show that metabolic changes precede clinical OTS diagnosis.
A 6-month prospective study of 150 endurance athletes, measuring insulin sensitivity (clamp or HOMA-IR), muscle GLUT4 (biopsy), glycogen (MRS), and lactate during graded exercise, tracking training load and performance to predict OTS onset.
Compare glucose metabolism parameters between OTS and non-OTS athletes.
A cross-sectional study of 100 endurance athletes (50 OTS, 50 controls), assessing insulin sensitivity, GLUT4 expression, glycogen storage, and lactate threshold using standardized protocols.
Synthesize current understanding of metabolic dysfunction in OTS.
A narrative review by exercise physiologists and endocrinologists summarizing evidence on muscle metabolism in overtrained athletes, discussing mechanisms and implications.