Type 2 Exercise with Type 2

Jim Lahey said:

I may be wrong, but I’m not sure that is entirely accurate. Although it’s commonly thought to be true, my understanding is that this perceived effect is brought about by muscle tissue being able to utilise glucose without the aid of insulin. In essence, any activity that requires even mildly strenuous use of skeletal muscle sucks up glucose like a sponge, irrespective of how much or how little insulin may be circulating at the time.

Obviously this would seem to materialise as increased insulin sensitivity, but in reality I think it’s just the body burning off glucose. Having said that, I guess it’s logical to argue that burning off glucose in cells does increases their ability to accept more from the blood, thus effectively increasing sensitivity. Hmmmm. Interesting.

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That is why I wrote the words "Basically (and I mean "basic" because that is all I understand) thereare two diabetes related things that happen when we exercise".
I find this easier to understand than lots of scientific sounding explanation the impact is the same.
I believe it is important to communicate in a language which is easy to understand.

Jim Lahey said:

burning off glucose in cells does increases their ability to accept more from the blood, thus effectively increasing sensitivity.

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Haven't you just explained reduced insulin resistance?

bulkbiker said:

Prof Noakes

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Big fan.
Loved him on Blue Peter.



Get Down Shep.

There is no Spoon said:

Haven't you just explained reduced insulin resistance?

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In a sense yes. Hence the last sentence that you didn’t quote EDIT: my point was that muscle tissue doesn’t require insulin at all in order to utilise glucose.

@helensaramay I wasn’t intentionally nitpicking your point, more just expanding on it.

Jim Lahey said:

muscle tissue doesn’t require insulin at all in order to utilise glucose.

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Hi Jim correct me if I wrong here, you're explanation was about increased insulin sensitivity and I was asking if that was another way of expressing IR as if they were two sides of the same coin.

"muscle tissue doesn't require insulin in order to utilise glucose" because the glucose is already present in the muscles and through exercise we use that glucose up? Am I correct not trying to put words into your mouth.

Exercise depletes stored glucose, forcing the body to replenish those stores internally "sucks up glucose like a sponge" with insulin facilitating the entry of glucose from the blood back into the muscles. As the muscles are less resistant they require less insulin to top up the stores thus more sensitive.

Perhaps its splitting hairs that increased sensitivity is not the same as less resistant.
But I think its a photo finish.

There is no Spoon said:

Hi Jim correct me if I wrong here, you're explanation was about increased insulin sensitivity and I was asking if that was another way of expressing IR as if they were two sides of the same coin.

"muscle tissue doesn't require insulin in order to utilise glucose" because the glucose is already present in the muscles and through exercise we use that glucose up? Am I correct not trying to put words into your mouth.

Exercise depletes stored glucose, forcing the body to replenish those stores internally "sucks up glucose like a sponge" with insulin facilitating the entry of glucose from the blood back into the muscles. As the muscles are less resistant they require less insulin to top up the stores thus more sensitive.

Perhaps its splitting hairs that increased sensitivity is not the same as less resistant.
But I think its a photo finish.

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Ah I see. Yes. Increased insulin sensitivity is essentially reduced insulin resistance. The other side of the same coin indeed. But again, my only point was that - to my knowledge - muscle tissue does not require insulin in order for it to to be able to utilise glucose in the blood. That being the case, exercise that uses significant skeletal muscle effort will burn glucose even if there is no insulin at all. In other words insulin sensitivity at that moment is moot, and not even required.

However, at the same time, because the body is burning the glucose (by hook or by crook), the overall sugar burden is reduced, thus improving sensitivity to insulin overall in the less immediate term...or reducing resistance. Perhaps a matter of perspective, or a chicken & egg question. Either way, the good news is that muscles continue to use glucose for several hours after the effort. To further complicate matters, there’s also muscle glycogen, which can only be used by the muscles, in the muscles. Unlike liver glycogen which can readily be converted back to glucose and shipped out into the blood for all the systems to use.

Also, as has already been touched upon, strenuous high-level aerobic or anaerobic exercise often triggers the release of stress hormones which will encourage the liver to to secrete glucose (the liver ‘dump’ that people speak of). That’s why many people experience raised blood glucose concentrations after exercising. I suspect this particular mechanism is probably influenced by whether or not the individual is well fat adapted, and how quickly their body is able to oxidise stored fat at a sufficient rate to cover the demand for fuel.

This is only my very broad understanding of the subject, and I’m not asserting it all as fact. Happy to be corrected on anything. Usually these things turn out to be way more complex than we could ever have imagined. I guess if it were easy we’d all have the answer to perfect human health. It’s fascinating stuff in any case

Jim Lahey said:

muscle tissue does not require insulin in order for it to to be able to utilise glucose in the blood

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That may well be the case Jim, I don't know enough about the molecular level stuff to even begin to tackle that statement with out a pot of coffee and a couple of hours to dive down the rabbit whole on google.

If you can throw up a link to something I would be interested.

That said insulin is, from everything I have read, the body's most efficient way of topping up the glycogen stores in the muscles and it seems one can say it is not required. That is not the same as saying it is not utilised. I would go further and say that for most people it is required.

You don't need carbs to live. But most people do eat them.
Just as most people to utilise insulin in replenishing glycogen stores with glucose stores. It seems to be the way it works for Joe Public, not some highly fat adapted long distance runner, so I assume it is the exception to the rule, to say insulin is not required. (this is just an guess on my part but seems to make sense, given my limited level of understanding)

Sorry Jim this can come across as nitpicking but its by whittling down these fine points that understanding is gained. So am I wrong is it more a specific case the insulin is not required? And not the general rule?

Jim Lahey said:

chicken & egg question.

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Egg. (I can prove it but sometimes I even bore myself)

Lastly

Jim Lahey said:

(the liver ‘dump’ that people speak of)

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Who are these people? Don't they know loose lips sink ships.

There is no Spoon said:

If you can throw up a link to something I would be interested.

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I found this link which seems to support the idea but of course doesn’t make it fact, particularly as the study used rats;

https://diabetes.diabetesjournals.org/content/34/10/1041

Abstract;

“It has recently been shown that insulin sensitivity of skeletal muscle glucose uptake and glycogen synthesis is increased after a single exercise session. The present study was designed to determine whether insulin is necessary during exercise for development of these changes found after exercise. Diabetic rats and controls ran on a treadmill and their isolated hindquarters were subsequently perfused at insulin concentrations of 0, 100, and 20,000 μU/ml. Exercise increased insulin sensitivity of glucose uptake and glycogen synthesis equally in diabetic and control rats, but insulin responsiveness of glucose uptake was noted only in controls. Analysis of intracellular glucose-6-phosphate, glucose, glycogen synthesis, and glucose transport suggested that the exercise effect on responsiveness might be due to enhancement of glucose disposal. After electrical stimulation of diabetic hindquarters in the presence of insulin antiserum, insulin sensitivity of 3-O-methylglucose transport was increased to the same extent as in muscle from healthy rats stimulated in the presence of insulin at 50 μU/ml. Furthermore, in muscle depleted of glycogen by contractions, transport of 3-O-methylglucose was increased in the presence of insulin antiserum and in the absence of increased regional perfusate flow. It is concluded that after exercise, increased sensitivity of muscle glucose metabolism to insulin can be found in the absence of insulin during exercise, but still involves increased membrane transport of glucose. At maximal insulin concentrations, the enhancing effect of exercise on glucose uptake may involve enhancement of glucose disposal, an effect that is probably less in muscle from diabetic rats. Finally, after exercise, increased glucose transport in glycogen-depleted muscle does not require increased muscle blood flow and, therefore, involves increased membrane permeability for glucose. The presence of insulin is not necessary for this effect of exercise.”

Jim Lahey said:

I found this link which seems to support the idea but of course doesn’t make it fact, particularly as the study used rats;

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Cheers Jim.

scottyjohn said:

Question is, for long endurance exercise what can I do to keep me from crashing?

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Hi scotty going back to your original question, sorry got side tracked, exercise snack to avoid bonking.

This is going to sound like I made it up but it is a real thing.
Take a mouth full of a sweet drink lucozade sport/coke swill it around your mouth and spit it out, like at the dentists. Tests show you can keep on going up to 25% longer.

• The sciency stuff: the mouth registers the sugar, thinks you adding more fuel and the body responds by shunting existing fuel to the muscles faster.

Hope that help with the bonking.