Based on: Lactate, Capnia, and Fat Oxidation as Therapeutic Axes for SARS-CoV-2 Spike Protein-Induced Sequelae — Hormone and Metabolic Research, 2026. DOI 10.1055/a-2794-9646
A large subset of people with post-acute COVID-19 syndrome — and those affected by post-acute COVID-19 vaccination syndrome — show changes in how the body produces and uses energy. Their symptoms frequently cluster into a trio: post-exertional malaise, fatigue, and cognitive impairment, sometimes described as "brain fog".
The review notes that this symptom pattern can be recreated by experimental perturbations that disrupt mitochondria. It also highlights laboratory (in vitro) work showing that the SARS-CoV-2 spike protein can disrupt mitochondria, offering a plausible mechanism for how these metabolic features arise.
The authors point to a striking physiological finding: patients with post-acute COVID-19 (vaccination) syndrome often have a severely reduced lactate threshold, meaning symptoms of overexertion can appear at low levels of physical output. Muscle biopsies in such patients have revealed disrupted mitochondria, and physiological studies show that fat (lipid) oxidation accounts for a significantly reduced share of total energy production and consumption.
Building on these observations, the review explores three connected therapeutic axes — lactate, carbon dioxide (capnia), and fatty-acid oxidation — as ways of approaching the underlying energy-production problem. It discusses interventions that aim to raise the lactate threshold, to increase tissue oxygenation (paradoxically, by raising the partial pressure of carbon dioxide), and to increase the proportion of energy obtained from fat oxidation relative to carbohydrate oxidation.
The authors draw analogies from exercise science to make the picture concrete: the condition resembles having an overabundance of fast-twitch muscle fibres, an oxygen supply more typical of high altitude, and what they describe as an inverse "fat adaptation" phenomenon — a state seen in endurance athletes, particularly those following low-carbohydrate diets.
By connecting these threads, the review frames the metabolic disturbances of post-acute COVID (vaccination) syndrome as interconnected rather than isolated, and argues that the lactate, capnia, and fat-oxidation axes deserve closer study.