Research
Hormonal
Prolonged exercise stimulates hepatic gluconeogenesis, with an increasing fraction of glucose output derived from blood-borne precursors like lactate, glycerol, and amino acids (especially alanine) as exercise continues.
Your liver makes new glucose from other substances (like amino acids and glycerol) during long exercise. This is a normal process that helps maintain blood sugar when glycogen runs low.
GoodSupportsHIGH confidence
Splanchnic uptake of gluconeogenic precursors (lactate, pyruvate, glycerol, alanine) had increased 2- to 10-fold after 4 h of exercise, and was sufficient to account for 45% of glucose release at 4 h as compared to 20-25% at rest and at 40 min of exercise.
Why this rating
Direct measurement of splanchnic exchange of precursors.
Source
Substrate Turnover during Prolonged Exercise in Man
G. Ahlborg et al. · Journal of Clinical Investigation · 1974
DOI 10.1172/jci107645
crossover · n=6Cited 786×
Read the paper DOI resolved against Crossref · corpus check 2026-06-10
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