Effects of two glucose ingestion rates on substrate utilization during moderate-intensity shivering.
Although the importance of food consumption to survive in the cold is well established, most shivering studies have focused on fuel selection in fasting subjects. Therefore, the aim of the present study was to provide the first estimates of exogenous glucose as well as liver and muscle glycogen oxidation rates of non-cold acclimatized men (n = 6) ingesting glucose in trace amounts (Control; C), and at rates of 400 mg min(-1) (Low Glucose; LG), and 800 mg min(-1) (High Glucose; HG) during moderate-intensity shivering (~3 times resting metabolic rate or ~20% VO(2max)) using indirect calorimetry and stable isotope methodologies. Exogenous glucose oxidation peaked at ~200 mg min(-1) at the lowest glucose ingestion rate (~400 mg min(-1)). In addition, glucose ingestion increased the contribution of plasma glucose to total heat production by ~50% but did not change the role played by muscle glycogen (~27% of heat production for control condition and ~23-28% for LG and HG). Instead, the contribution of liver-derived glucose to total heat production was reduced by 40-60% in LG and HG, respectively. In conclusion, glucose ingestion even at low rates contributes a significant proportion of total heat production during moderate intensity shivering and reduces the utilization of liver-derived glucose but not muscle glycogen.
Faculty of Health Sciences, School of Human Kinetics, University of Ottawa, 125 University St., Ottawa, ON, K1N 6N5, Canada.
Denis P
DP
Blondin
Isabelle
I
Dépault
Pascal
P
Imbeault
François
F
Péronnet
Marie-Andrée
MA
Imbeault
François
F
Haman
D001786:Blood Glucose / Q000378:metabolism; D005947:Glucose / Q000378:metabolism*; D006003:Glycogen / Q000378:metabolism; D006801:Humans; D008297:Male; D010084:Oxidation-Reduction; D012768:Shivering / Q000502:physiology*; D013696:Temperature; D055815:Young Adult
D001786:Blood Glucose; D006003:Glycogen; D005947:Glucose