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Fasting Type 1 - what to do about exercise?

Jasmin2000

Well-Known Member
Messages
184
Type of diabetes
Type 1
Treatment type
Insulin
I thought I would try this fasting business as a way to eliminate the highs I'm getting from protein or fat (can't tell which, but it's not carbs).
So I reduced basal and use the higher than desired BG for exercise, such as walking to work. But very quickly I'm going low so how do I prevent hypos when fasting and still exercising? I'm not in the zone where my body just burns fat when needed.
 
Could you eat some carbs at this point, they are effectively FoC re dosing and shouldn't produce a spike? Or is not eating any carbs a requirement?

The other option is to up the pace a bit so that your liver starts to produce glucose. I suggest this but can't produce the effect when walking (I will always go low) so it's more of a theoretical suggestion (but we're all different). I can sit in this useful "location" (enough activity to stimulate the liver, not so much that I require lots of carbs) when cycling - I often start medium length rides semi-fasted (very few carbs, often just the milk from a couple of coffees) because I don't want the spike from a decent breakfast nor do I want any additional active bolus on board.

Sorry I don't have a direct answer.
 
The only way to increase BG when hypo is to eat carbs. Forget fasting, stopping a hypo is far more important.

In my experience, “upping the pace” is likely to bring on a hypo faster. Yes, the liver will dump more glucose but that Is because the muscles need that glucose.
It is only when the body is stressed that the BG can increase through exercise. This may be due to interval training, heavy weights or something like a tough slog uphill against a strong wind, preferably in the pouring rain.
 
In Response said:
The only way to increase BG when hypo is to eat carbs. Forget fasting, stopping a hypo is far more important.
Click to expand...
I meant to up the pace pre-hypo, or when dropping, which is actually what EXTOD suggest too.

Once you're hypo I would expect that the liver would start to do its thing anyway due to stress hormones even if endogenous glucagon production due to low BG is prevented by IoB or the general reduction one (apparently) gets with T1 diabetes.

It does depend on what "it" is. As I mentioned above I don't find that this works with walking, though one of the suggestions from EXTOD is to break into a sprint if BG is dropping. I've never tried this while walking, but it does work while riding, at least in the early stages while the liver still has some glycogen it's willing to spare.

There's presumably a trade-off between stress hormone half-life (i.e. how long will the liver keep producing glucose) and requirement to replenish in-muscle glycogen stores both from the original activity and whatever the "sprint" event required. More of a "get you home" type thing, though the liver does contain quite a lot of stored glycogen, so the getting home might theoretically be 1h30+ if you can judge it just right....
 
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Thanks for the ideas. A no-carb fasting is not a necessity - I was just wondering how an average T1 would cope with the need for BG when exercising (as opposed to those who have flipped their metabolism). I've never been able to get my liver to dump on demand - I can cruise along just under 3.9 for hours and no BG rise. But I do use the Dawn Phenomenon/Feet-on-the-Floor spikes to exercise - that's a free BG with no carbs! I also use the dumps from coffee, short burst of anaerobics and stress (talking to my mum) to fill up the BG tank and do more exercise.

That takes care of a third of my daily routine but looks like the rest will need drip feeding BG - now that could be carbs, but I've found that a chunk of cheddar or tub of quark also gives me substantial BG rise (not a spike but a plateau) after a while. I like the idea of slower exercise too - that would avoid a sudden drop.

In Response said:
The only way to increase BG when hypo is to eat carbs. Forget fasting, stopping a hypo is far more important.
Click to expand...
Yes I agree. I'm not trying to get into a hypo, but to find enough BG to exercise during fasting. Today I did all of the stuff above and have done 4 hours medium-pace exercise (slow bike ride for 90 min, walking for 30 min, anaerobics for 60 mins. Together with a reduction in basal to 50% and no fast-acting, I've kept in range.

Trying to avoid going down that path - I'm not going to rely on counter-regulatory responses to provide BG to reverse a hypo, so I stop exercising if BG is falling.
 
Hi
Years ago i read an article that chicken whilst is carb free eventually turns into a carb and you should dose for it.
I dismissed this as nonsense as i'm a seasoned pro and have never factored it in.
However however a while back i was peckish and had no fast acting insulin on board and in the fridge was a chicken leg left over from the day before.
I ate it and monitored my levels......

It took a good 2 hours but blow me my levels rose and quite sharply too once i got digesting said chicken.

So what is the chicken?
Carb or protein?

Someone more knowledgeable will explain this better i feel sure but maybe its worth a try.

I wish you well

Tony
 
Tony337 said:
So what is the chicken?
Carb or protein?
Click to expand...
The chicken is protein.
However, in the absence of carbs, he body can breakdown protein into glucose.
This is why, when you eat a no carb/low carb meal you will have to bolus for protein.
Although the guidance is usually that insulin to protein ratio is half that for insulin to carbs, in my experience the insulin to protein ratio varies for different types of protein and needs to be taken later.
I prefer to eat some carbs and not have to worry about it.
 
I'm guessing it may well vary from person to person, but there is presumably a ratio of carbs to protein (or fat, for which a similar process can take place, though it depends on the type of fat as only some can be converted to glucose) that prevents any protein conversion to glucose.

I eat a reasonably high ("normal") carb diet, so have never tried to measure this point, but perhaps someone on a lower carb diet has some insight into this?
 
I'm low carb so I have to bolus for protein. For those eating higher amounts of carbs, the glucose from protein is less of an issue and the small amounts don't spike but add to background BG over 6-9 hours - which is balanced by your basal. If you go low carb, the body needs to get glucose from protein and fat so the conversion (gluconeogenesis) is faster and contributes much more to your BG. You were probably triggering this with your chicken leg from a period of low carb.

@In Response and @SimonP78 are both correct about needing carbs to prevent spikes from protein. For me too many carbs (>50g/day) makes me sick to I've been a protein/fat case since I was a child and have learned how to bolus. Essentially, I now get protein BG spikes similar to a carb spikes but with a delay - no longer a slow 6-9 hour BG rise but a real post-prandial spike after 1-2 hours. Downside is only that the foods that most T1s class as "safe to binge on" like cheese, cream, tofu, and of course, meat need to be bolused.
 
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