Endurance Training Increases Gluconeogenesis During Rest And Exercise In Men

[Hugh Johnson]

Abstract

The hypothesis that endurance training increases gluconeogenesis (GNG) during rest and exercise was evaluated. We determined glucose turnover with [6,6-2H]glucose and lactate incorporation into glucose by use of [3-13C]lactate during 1 h of cycle ergometry at two intensities [45 and 65% peak O2 consumption (V˙O 2 peak)] before and after training [65% pretrainingV˙O 2 peak], same absolute workload (ABT), and 65% posttrainingV˙O 2 peak, same relative intensity (RLT). Nine males (178.1 ± 2.5 cm, 81.8 ± 3.3 kg, 27.4 ± 2.0 yr) trained for 9 wk on a cycle ergometer 5 times/wk for 1 h at 75%V˙O 2 peak. The power output that elicited 66.0 ± 1.1% ofV˙O 2 peak pretraining elicited 54.0 ± 1.7% posttraining. Rest and exercise arterial glucose concentrations were similar before and after training, regardless of exercise intensity. Arterial lactate concentration during exercise was significantly greater than at rest before and after training. Compared with 65% pretraining, arterial lactate concentration decreased at ABT (4.75 ± 0.4 mM, 65% pretraining; 2.78 ± 0.3 mM, ABT) and RLT (3.76 ± 0.46 mM) (P < 0.05). At rest after training, the percentage of glucose rate of appearance (Ra) from GNG more than doubled (1.98 ± 0.5% pretraining; 5.45 ± 1.3% posttraining), as did the rate of GNG (0.11 ± 0.03 mg ⋅ kg− 1 ⋅ min− 1pretraining, 0.24 ± 0.06 mg ⋅ kg− 1 ⋅ min− 1posttraining). During exercise after training, %glucose Rafrom GNG increased significantly at ABT (2.3 ± 0.8% at 65% pre- vs. 7.6 ± 2.1% posttraining) and RLT (6.1 ± 1.5%), whereas GNG increased almost threefold (P < 0.05) at ABT (0.24 ± 0.08 mg ⋅ kg− 1 ⋅ min− 165% pre-, and 0.71 ± 0.18 mg ⋅ kg− 1 ⋅ min− 1posttraining) and RLT (0.75 ± 0.26 mg ⋅ kg− 1 ⋅ min− 1). We conclude that endurance training increases gluconeogenesis twofold at rest and threefold during exercise at given absolute and relative exercise intensities.

http://ajpendo.physiology.org/content/278/2/E244.long

I wonder if actually cardio has value. Glucose metabolism is superior to fat metabolism after all.

 

[burtlancast]

Maybe this is the explanation on why chronic exercise improves the general well being and performances ?

 

[LucH]

I wonder if actually cardio has value. Glucose metabolism is superior to fat metabolism after all.

We know that exercise increases metabolism at rest for 48-72 hours. So as for gluconeogenesis. And of course this increases the level of endorphins, which explains the feeling of well-being after sports.
Best if minimum half an hour, cardio frequency: Jogging, cycling, swimming, aerobics, interval training, football, athletics, etc.
We need some glucose for fueling up well. Not much: A orange is enough.
"We burn fat in contact with carbohydrates."
Glucose is superior but only in period of intense stress / brain work.

Exerpt:
Our genes really appreciate the frequent movements performed at a slow, comfortable rythm such as walking, hiking, biking or other light aerobic activities where the heart rate is between 55 and 75% of maximum heart rate.
Source: Mark Sisson. The Primal Blueprint

LucH

 

[Hugh Johnson]

Sorry, I can't take a man that sells fish oil seriously. I'm not going to take Sisson's word for anything.

Maybe this is the explanation on why chronic exercise improves the general well being and performances ?

Yeah, I do intent to look up some more studies when I have the time. Anecdotally it does work, and other studies I haven't read yet suggest the same. It's one more tool to more away from fat/stress metabolism.

Wouldn't recommend intense exercise to anyone in a lot of stress or with a lot of PUFA stores, though.

 

[paymanz]

isnt gluconeogenesis means catabolic state in which glycogen and proteins break down to form glucose?

 

[LucH]

isnt gluconeogenesis means catabolic state in which glycogen and proteins break down to form glucose?

yes, this is an aternative fuel, when deprived from carbo or fat. additionnal work for liver.

LucH

 

[Hugh Johnson]

isnt gluconeogenesis means catabolic state in which glycogen and proteins break down to form glucose?

Also fat. Catabolic state has to do with stress.

http://www.ncbi.nlm.nih.gov/pubmed/22584514

http://blog.cholesterol-and-health.com/ ... fatty.html