Elevated blood lactate in resting conditions correlate with post-exertional malaise severity in patients with Myalgic encephalomyelitis/Chronic fatigue syndrome. — CFSMEATLAS
Elevated blood lactate in resting conditions correlate with post-exertional malaise severity in patients with Myalgic encephalomyelitis/Chronic fatigue syndrome.
Ghali, Alaa, Lacout, Carole, Ghali, Maria et al. · Scientific reports · 2019 · DOI
Quick Summary
This study looked at lactate levels (a substance produced by muscles) in the blood of ME/CFS patients who were at rest. Researchers found that about 45% of patients had higher-than-normal lactate levels even when not exercising. Importantly, patients with elevated resting lactate tended to experience more severe post-exertional malaise (the symptom flare-ups that follow physical activity).
Why It Matters
This study provides objective biological evidence that resting lactate elevation may be a measurable biomarker in a subset of ME/CFS patients, potentially helping identify those at risk for severe post-exertional malaise. Identifying such biomarkers is important for understanding disease mechanisms and could eventually inform personalized management strategies.
Observed Findings
44.7% of ME/CFS patients (n=55/123) had elevated resting blood lactate (≥2 mmol/L)
Elevated and normal lactate groups were otherwise clinically comparable
Post-exertional malaise severity was significantly higher in the elevated lactate group
After adjusting for confounders, elevated resting lactate was associated with 2.47-fold increased odds of more severe PEM
55.3% of patients (n=68) had normal resting lactate levels despite confirmed ME/CFS diagnosis
Inferred Conclusions
Elevated resting lactate identifies a biologically distinct subgroup within ME/CFS patients
Resting lactate may be a useful clinical marker for identifying patients at higher risk for severe post-exertional malaise
Resting lactate assessment could potentially inform clinical management strategies and risk stratification
Remaining Questions
Does resting lactate elevation predict future PEM severity in prospective studies?
What is the mechanism linking elevated resting lactate to more severe post-exertional malaise?
Do lactate-elevated and lactate-normal ME/CFS subgroups differ in their exercise-induced lactate kinetics and responses?
What This Study Does Not Prove
This study does not prove that elevated lactate causes post-exertional malaise or identify the underlying mechanism. The retrospective design and lack of control group limits causal inference. The study cannot determine whether lactate elevation is primary or secondary to other disease processes, nor does it establish whether resting lactate predicts PEM severity prospectively.