To assess early-onset differences in glucose metabolism in patients with sepsis during the first day of ICU hospitalization and evaluate these differences vis-à-vis shock resolution, we studied 10 (8 men; mean age+SD: 58+20 years) mechanically ventilated patients with a diagnosis of septic shock. On day 1 blood and microdialysis (MD) samples were collected twelve times per day (every 2 hours) for glucose and lactate in blood and for glucose, pyruvate, lactate and the lactate to pyruvate ratio in tissue (with MD). Six patients recovered from shock within 1-9 days. In patients with shock resolution significant (positive) correlations were noted for MD glucose and MD lactate versus blood lactate and MD pyruvate versus MD lactate, all with no lag. Septic shock patients that showed elements of persistent adipose tissue glycolysis early on had better prognosis compared to those patients that did not show glycolysis.