This article by Peat:
http://raypeat.com/articles/articles/co2.shtml
contains this passage:
"In eccentric exercise and denervation, less oxygen is used and less carbon dioxide is produced, while lactic acid increases, displacing carbon dioxide, and more fat is oxidized. Prolonged stress similarly decreases carbon dioxide and increases lactate, while increasing the use of fat."
I certainly understand the idea that some kinds of exercise favor anaerobic glycolysis, and yes that creates lactic acid instead of CO2. But why would he believe that anaerobic glycolysis oxidizes more fat? Why would fat burning create lactic acid instead of CO2?
When we are at rest or low levels of exertion, are we always in anaerobic metabolism, or is this also krebs cycle? How much of this activity gets fuel from fat instead of glucose?
I thought that sustained periods of aerobic metabolism at some point switch from glucose to fat burning? What aerobic metabolism cycle is involved in such fat burning as part of aerobic metabolism? Does that process not have CO2 as the output?
Assuming that the fat burning in aerobic metabolism is "oxidative phosphorylation" this article from Wikipedia seems to support my line of questioning:
http://en.wikipedia.org/wiki/Oxidative_phosphorylation
Quoted section:
"The amount of energy released by oxidative phosphorylation is high, compared with the amount produced by anaerobic fermentation. Glycolysis produces only 2 ATP molecules, but somewhere between 30 and 36 ATPs are produced by the oxidative phosphorylation of the 10 NADH and 2 succinate molecules made by converting one molecule of glucose to carbon dioxide and water,[4] while each cycle of beta oxidation of a fatty acid yields about 14 ATPs. "
http://raypeat.com/articles/articles/co2.shtml
contains this passage:
"In eccentric exercise and denervation, less oxygen is used and less carbon dioxide is produced, while lactic acid increases, displacing carbon dioxide, and more fat is oxidized. Prolonged stress similarly decreases carbon dioxide and increases lactate, while increasing the use of fat."
I certainly understand the idea that some kinds of exercise favor anaerobic glycolysis, and yes that creates lactic acid instead of CO2. But why would he believe that anaerobic glycolysis oxidizes more fat? Why would fat burning create lactic acid instead of CO2?
When we are at rest or low levels of exertion, are we always in anaerobic metabolism, or is this also krebs cycle? How much of this activity gets fuel from fat instead of glucose?
I thought that sustained periods of aerobic metabolism at some point switch from glucose to fat burning? What aerobic metabolism cycle is involved in such fat burning as part of aerobic metabolism? Does that process not have CO2 as the output?
Assuming that the fat burning in aerobic metabolism is "oxidative phosphorylation" this article from Wikipedia seems to support my line of questioning:
http://en.wikipedia.org/wiki/Oxidative_phosphorylation
Quoted section:
"The amount of energy released by oxidative phosphorylation is high, compared with the amount produced by anaerobic fermentation. Glycolysis produces only 2 ATP molecules, but somewhere between 30 and 36 ATPs are produced by the oxidative phosphorylation of the 10 NADH and 2 succinate molecules made by converting one molecule of glucose to carbon dioxide and water,[4] while each cycle of beta oxidation of a fatty acid yields about 14 ATPs. "