For the longest time I was envious of people that had access to Afrezza. No longer. I realized that just 5 minutes on my elliptical brings me down from 120 mg/dL to 80 mg/dL. That is all I was looking for. Amazing.
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If only you could fit an elliptical in your pocket
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Do you spike shortly after that though? I do! ;-(
So far I haven’t spiked. I have done it only a handful of times. Without exercise I would peak at 140 mg/dL. My only goal is to stay below 120 mg/dL. Before using the elliptical I sometimes went for a walk. Walking was not very effective. My guess is that 5 minutes on the elliptical is as effective as 20 minutes of walk. This is a big difference for a person that has no patience.
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Glad to hear no spikes. We have the same goal, stay under 120. Today I way over shot. Shot up to 200 after my run. This is very unusual for me so probably something else going on.
Great question!!
A BG spike after exercise is common. It is more pronounced if the exercise is anaerobic…like weight lifting. Yes running is not usually considered anaerobic but it does use the large muscle groups.
Muscles store glucose for immediate use when required. Anaerobic exercise taps the muscle stores and consumes the stored glucose. After exercise is over those stores are replenished. The liver, which stores energy as glycogen, will initiate conversion of glycogen to glucose. This “converted” glucose is secreted into the bloodstream, hence, a BG spike after exercise. A work colleague of mine first brought this to my attention when he borrowed a CGM from me. He is non-diabetic but an extreme keto fanatic. He wanted to know how his BG varied as a result of his keto-diet and exercise. He logged his CGM data with Tidepool and noted his own BG spike after an intense weight lifting session. This peaked my interest so I did my own trial. I intentionally took no calories before weight lifting one evening(before dinner). My pre-workout BG was 87. My BG dropped a bit at the beginning of the workout as my heart rate increased. By the middle of my workout, my BG had stabilized to the mid nineties. Afterward, with no meal, my BG gradually rose to 169(glucogenesis via stored glycogen) over a two hour period. After the 169 peak, my BG began to drop as the muscle groups recouped their stores from the blood and there was essentially no new calories since lunch time. The liver began using the present insulin from the pump to convert the BG to its glycogen stores. This of course go on in perpetuity…I did have to eat eventually, but, it was an eye opening event for me. I wish I had understood this before 36 years as a T1D…I would have used it to better regulate my activity to calories over the years…not that I am overweight or underweight…better regulation of calories translates to better BG control.
The five minutes of elliptical is a quick burst of aerobic exercise that increases heart rate quickly and yes it uses large muscle groups but with less resistance than propelling ones own body across the ground. The heart also has to use glucose for energy and it is always beating…the heart cannot store glucose like the other muscle groups…it is never at rest
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Thank you! This is an excellent overview of what happens post exercise. This has been my experience as well! I usually spike within 20 minutes of my run end. To head it off, I will take insulin while still running, but I have to be careful to time it right or I will go low while still running! For example, yesterday I started to spike DURING the run at about mile 6. So I took 0.2U and then still going up, so another 0.3U, at BG 143. Then I started to drop, so I headed back. By the time I ended the run, I was 81, then dropped to 61 over then next 10 minutes while stretching. Interestingly, I never spiked post run. I gradually went up to 86 over the next few hours. No spike. Still that is not the usual case. Usually, I do not spike at all 'til after I stop. Taking a bit of insulin during the run did head off the spike at least!
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Maybe it is the type of exercise that I do, but I never spike. Often I need to eat dried fruit or candy while I exercise in order to not go lower than 65. I ride my exercise bike for an hour every day bringing my heart rate up from the 60’s to around 110. Not really high, but good enough I hope.
I don’t spike later.
Type 1 dx 1959
That makes sense. You are running with no insulin, or highly reduced basal.
But your body does not need much insulin during that time, as long as you are below a certain level of your lactate threshold.
When done at a sufficient intensity and duration, muscle contraction during exercise allows glucose transport independent of insulin.
But…as soon as you stop, all of that time with reduced basal catches up to you. You are no longer running, so the muscle contraction-meditated pathway is no longer available.
That can happen if intensity is far below threshold (lower intensity), or too close to threshold (higher intensity).
It is helpful to learn levels of intensity, and how they affect you. One of the main markers you can establish is lactate threshold level.
Lactate threshold is the highest intensity that you can maintain for about 30 minutes, where you are not experiencing a rapid accumulation of lactate in your blood.
Once you have that level, you can use all kinds of formulas to calculate how much fat your are using for fuel versus muscle glycogen. And where your inflection point will be for spiking and dropping.
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Thanks, Eric! Yes, this is exactly what seems to be happening most of the time, and I’m usually prepared to give myself some insulin just before the run end to counteract the spike. I usually (if BG < 95) have a 21g Huma Plus right before the run, and I take no bolus for it, anticipating that I will need it for the run. My IOB is usually around -0.2U to 0.2U. My BG usually stays in pretty close range to where I start, but there are these off days 
I don’t think I’m changing my running intensity on these off days, but maybe!
I’ve never tested my lactate threshold but I’ve read about it here! Worse, even though I’ve been using trainingpeaks.com (your recommendation 
) I’ve not done the lactate test as described here.
To find your LTHR do a 30-minute time trial all by yourself (no training partners and not in a race). Again, it should be done ***as if it was a race for the entire 30 minutes*** . But at 10 minutes into the test, click the lap button on your heart rate monitor. When done, look to see what your average heart rate was for the last 20 minutes. That number is an approximation of your LTHR.
I don’t have a heart monitor, but I can use my apple watch with a workout in iSmoothRun to get the last 20 mins HR. Next good weather day I’ll try it!
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The heart rate value is useful for many aspects of training. It would be great to get an accurate one if you want to get into it. The best one is the Wahoo TICKR.
(Just to make sure everyone reading this is on the same page, LTHR is lactate threshold heart rate.)
Some cool things you can do with your lactate threshold pace and LTHR - if you know your lactate threshold pace, and you go on a run where your HR does not decouple very much (stays relatively consistent compared to speed), and your HR is at around 80-85% of LTHR, you will know you are burning about 50% fat and 50% glycogen. That is a great starting point to use in training for a marathon, because it gets you to the finish line without hitting the wall (you generally have about 13 miles of muscle glycogen in your legs at marathon pace).
You can use that LTHR value for all kinds of races. Different percentages of LTHR fit with race distances of 5k all the way through marathon.
You can use your LT pace for various races, instead of using LTHR.
BTW, I have a good video I can send you that talks about some nutrition things for exercise, if you want to see that.
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Ha, I sort of thought the Apple watch wasn’t the most accurate! 
I know it isn’t in tracking mileage either.
Wow, I didn’t know that. Good reason to know that LTHR! Even in the case when your running partner decides we do a 20 miler instead of a 10 miler!
Is the “LT pace” just your pace where your HR is 80-85% (depending on race) of LTHR?
That would be awesome! You probably know I’m vegetarian, but I don’t eat anything specifically for exercise, except for the Huma gels!
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No. I did not explain it very well. I will try to do better.
Imagine your LT pace is how fast you can go for 30 minutes all out. It is not like a 30 minute race, where you are planning on having a kick at the end. Or if you are planning on a race strategy, and adjusting your speed.
LT pace is how fast you can run for 30 minutes, as hard as possible, at a constant speed.
You had some of that quoted above…
To find your LTHR do a 30-minute time trial all by yourself…
…
…That number is an approximation of your LTHR.
But while your LTHR is focusing on what your HR is in that 30 minute trial, LT pace is just focusing on what your pace was during the time trial.
Once you get your LT pace figured out, that 30 minute LT pace is a very useful number for calculating your pace for various distances!
You use 105% as the multiplier for each double of the time you are running.
Here are some examples of how you might use it.
Suppose your 30 minute LT pace was an 8:00 / mile.
Your expected pace for a 60 minute race would be 105% of that pace, which is 8:24 (8:00 pace x 105% = 8:24 pace).
Each doubling of time increases it by another 5%.
| Time of run: | Expected pace: | |
|---|---|---|
| 30 Minutes | 8:00 | |
| 60 Minutes | 8:24 (8:00 x 105%) | |
| 120 Minutes | 8:49 (8:24 x 105%) | |
| 240 Minutes | 9:15 (8:49 x 105%) |
See how the pace for each successive doubling of time is 105% of the previous pace?
So if you were then racing a 10k or half or marathon, you could look at the 1/2 hour, 1 hour, 2 hour, and 4 hour paces, and have an idea of a general area of where you might be able to target.
Of course these are all ballpark numbers. And some people do better or worse at the various distances. But it gives you a general idea.
Try it out and see how closely it matches your expectations. Think of what you could hit in a 30 minute trial. And then see if the 105% increase works for 1 hour, and then 2 hours, and then 4 hours, etc.
I did not know that. But the video does talk about that a little bit. For plant based athletes, they need to take care to make sure they are supplementing with some of the things that you can’t get from plants. Things like vitamin B12, you can’t get that from plants. And some of the amino acids are hard to get in sufficient quantities with plants.
The video discusses that a little bit, and talks about proper supplementation if you are vegan. But it is not judgy at all. There is no agenda in it. It’s geared toward helping people, not trying to get them to do any one particular thing.
BTW, you could probably get a script for B12 injections that you could do yourself. The general script for that is 1cc via IM injection, once a month. For an experienced D like yourself, the injection and the whole thing would be nothing for you.
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Thank you for your excellent description of the LT pace. This makes sense, and now I know how I can use it, too. Thank you for the examples! I think your example of 8 min/mile could actually apply to me, but I still want to do the 30 min LTHR test. I just need to find some flat surface that I can run for 30 minutes. I think the local track is closed and my normal running routes all include hills but I’m sure I can fit 30 minutes of running in somewhere!
Oh, sorry, I meant that I am vegetarian, but I am not a vegan. I just restrict meat and poultry. So I have lots of other options for B12 
Still, I could be deficient especially as I have thalassemia minor which is a red blood disorder. Something for me to research!!
Yup it’s gold. I take no fast acting 90 % of the time. I couple my walks with my meals and I’m good to go!!! Since Jan I only injected Humalog once and it was cause I pigged out! Quarantine stress caused a total meltdown.
My long acting is Tresiba