Your donations help T1Determined #keepgoing.

T1D and Pushing Your Limits without Pushing Yourself Over a Cliff

Those of us who want to test our limits all know that feeling you have when you’ve gone too far.

We push through the pain, or exhaustion, or–if you’re a type 1 diabetic–ignore the weird, anxious feeling, that intangible “aura” that things are not right–and continue anyway, only to pay the price: rashes, blisters, sciatica, unwanted weight loss, fever, hallucinations, or wolfing down glucose shots at 3:48 in the morning, glucagon in hand, unable sit up without collapsing, wondering if we’re going to die.

It’s that fear of going over the proverbial cliff that keeps many of us from starting. Take me, for instance. Due to my justifiable fear of blood sugar drops caused by exercise, I consciously avoided physical activity for 30+ years, until at the age of 42 I discovered it wasn’t the bear I was running from (low blood sugars) that was going to kill me, but the mountain lion (high blood sugars) that I had been ignoring.

So how do you get past something like this?

A rocky start

I was fortunate that in 2004, after a retinal laser treatment that left me with a permanent blind spot intended to save me from even worse complications; and now having more worries about complications than low blood sugars, I decided to face my fears and sign up for a 5K.

I was terrified. Every time Leslie and I headed downstairs to the workout room in the building where we lived, I knew my blood sugar was going to drop. It always did.

Which was fine as long as it was 200 mg/dl or thereabouts. Except that it wasn’t always. I was trying harder to be in good control. After 30 years of taking exactly the same amount of insulin every day and at every meal regardless of what I ate (imagine how badly THAT went!), I had seen a dietician and a DNE (diabetes nurse educator) to talk about carb counting and dosing appropriately. My A1C was down from above 13 mmol to closer to 9. Leslie and I had thrown out our large plates and replaced them with saucers. I ate smaller portions and had begun to lose some of my excess 50 pounds in a healthy way.

Every time I headed down to the workout room, I’d start with my blood sugar around 140 mg/dl (I wasn’t comfortable yet starting exercise with a normal BG) and every single time, by the time I was 20 minutes into it, my sugar would be 70 mg/dl. I’d have to stop exercising and eat, which kind of defeated the purpose.

Then somehow, just when I needed to hear it, a friend told me to talk to Ginny Ives at the Ruth Collins Diabetes Center. Ginny taught me about “exercise equivalents.”

Two steps forward, one step back

The idea behind exercise equivalents is that you use the fact that exercise lowers blood sugar as a tool. Figure out for yourself just how many minutes of a particular type of activity lowers your blood sugar by how many mg/dl. Then treat exercise as if it were insulin.

For a few years now, there have actually been some pretty good handbooks out there for this type of thinking. Probably the best (and best known) is Sheri Colberg-Ochs’ The Diabetic Athlete’s Handbook. Colberg-Ochs’ book covers a wide range of exercise and has some pretty good estimates of the degree to which each lowers blood sugar. Obviously, the exact amount depends on a lot of factors such as your weight, current fitness level, stress level, and insulin sensitivity. It’s not an exact science.

But it is a tool. Treating exercise as if it were insulin meant that whenever I normally took insulin–whose primary purpose is to enable the body to store energy–I could use less of it because I was storing less energy and using more.

I still had problems, though. Sometimes I’d push a little harder and reap the results as the same kind of bad lows I had feared for 30 years, and still do.

Taking smaller steps…baby steps, even

One thing I learned through practice is that if you’re going to push things, you should never get that far outside your comfort zone in a single attempt.

If you’re training to run a 5K, find out what your blood sugar does after just 1 mile, then scale it up.

Experiment with fueling strategies. Look at what you ate before you headed out, what you may eat during your workout (or depending on the type and length of workout, whether you should), and what your blood sugar does afterwards.

Does it plummet? Spike? Go up slowly and stay there? Go up slowly and drift back down? Each of these may have different causes, and the only way you’re going to find out which cause matches which effect is through experimentation.

Tweak one thing at a time: pre-workout fuel amount, workout duration or intensity, in-workout fuel amount, post-workout recovery fueling, food composition (carbs vs fat vs protein), and so forth. Just one thing, though, not all of them.

How (and how much) to push your limits

Take time to do some “not pushing it” workouts where you get used to the results your previous strategy accomplished. Do these enough that you start to recognize patterns.

Then occasionally, push the limits.

It’s a good idea, however, to not extend what you’re doing by more than 15%. That’s usually not enough to put you in any real danger from overtraining, underfueling, overfueling, overdosing, underdosing, or anything else.

Gather blood sugar data like crazy. You will need it. Analyze it and look for patterns.

When you think you see a pattern, run little experiments. For instance, if you sugar spikes after your workout (which happens to a lot of us), don’t just fully “dose it down” right away. You might be insulin sensitive. You might be experiencing stress. You might be dumping glycogen. You might have overfueled.

Each one of those is going to require a different strategy to address, so it’s important to experiment with various types of dosing and recovery carbs to see what’s really going on.

Give your little experiments time to work. Don’t pile one on top of the other. That just confounds the data. Measure the results.

With practice, you’ll discover your own safety margin. You’ll be able to figure out over time when you need to get something to eat without it blowing your whole workout to smithereens. You’ll be able to get back up on the treadmill or your bike or in the pool and continue your workout. You’ll find you can go longer without losing your rhythm or cooling down so much it doesn’t make sense to continue.

Make your safety margin as big or as little as you need to give yourself both the data you need and an increasing sense of control over outcomes.

Then repeat the process.

When not to push limits

The “push 15% then pull back to normal” strategy works reasonably well for quite a while. I used it up until the point I was training for marathons, a challenging effort that can be accomplished in a single day.

With marathons, once you’re done, you can grab a recovery snack, go home, get a hot shower, massage your tired muscles, and crash.

But beware. If marathons are the kind of thing you do once a year, expect your blood sugar to drop precipitously when you go to sleep. You’ve significantly depleted glycogen stores and if you haven’t eaten enough of a recovery meal, you won’t have replenished those stores. You’ve probably lost some potassium that you haven’t replaced adequately with a sports drink. Your blood sugar will probably have spiked at the end of your run due to any of several factors, and you’ll probably have tried dosing it down only to find it doesn’t go down. That’s probably stress or excess glycogen, but your body is doing that for a reason, and it’s not specific just to diabetics. You’ll also be insulin sensitive.

This is a perfect storm that can lead to what’s known as “dead in bed” syndrome: you’re insulin-sensitive, glycogen and potassium depleted, and probably have too much insulin on board. Your brain needs glycogen and will try to increase the glucose concentration in your blood by “sweating out.” You lose even more potassium from the sweating, and eventually, unable to wake up from a dangerously low blood sugar, your potassium-depleted heart can’t continue beating.

Forget what people say about dying peacefully in your sleep. It’s a sucky way to go, and like many of you, I’ve been close enough to know that.

THAT is the thing people with type 1 fear when they START an exercise program.

It’s kind of a sick joke that after spending years working up to doing a “good thing”–running a marathon–you get your butt handed to you by that same good thing, as a reminder not to push things too far.

So I’m telling you in advance–take me seriously when I say don’t get cocky.

Sometimes you have to just find out

When you’re overdriving your headlights on the blood sugar management front is the time you should be most careful about following a controlled, predictable, data-rich process that minimizes risk.

Perhaps the hardest thing for me was having to discover on my own what worked for me and what didn’t when I started doing events longer than a marathon.

Up until then, I’d been able to rely on fellow diabetic athletes in an organization I had helped put together, called the Diabetes and Exercise Alliance. It originally started out as a chapter of the fledgling Diabetes Exercise and Sports Association and got handed through several organizations including InsulINdependence, Beyond Type 1 and Type 1 Run. Our little team of what my endocrinologist calls “Mutant Diabetic Superheroes” has been a great resource for that kind of thing.

But by the time I started training for my first full Ironman, first 100 mile run, and first 200 mile run, all in 2017, I found I had fewer and fewer examples to copy. I’d heard of a guy named Stephen England who ran 100 milers. I had heard of Doug Masiuk, the first Type 1 to run across the USA. And I’d heard casually about a handful of other Type 1s who had done Ironmans. But for the most part, going to a Type 1 and exercise focused FB group or other forum resulted in the same answer: “I don’t know…let me know when you find out.”

So that’s what I did.

For the Ironman, fortunately, I knew already what it felt like to run a marathon…but not after swimming two and a half miles and riding my bike over 100 miles more. I was weakest on the bike and had the least data there, so I signed up for a moderate number of “centuries” (100 mile bike rides) to get ready for the 112-mile bike ride for the Ironman. I learned to swim in open water, first for a mile, then for 2.4 miles.

Each time, I did only one sport at a time, and took my time to stop and test my sugar. Then I moved onto doing “bricks” (more than one triathlon sport in a day, sometimes cutting the distance short if necessary) to get a sense of how transitioning from swimming to cycling or cycling to running affected my muscles, stamina and blood sugar.

Sometimes there were surprises. I found that swimming when I couldn’t see where I was going was a bit harder than usual. It took extra effort to sight and swim at the same time, and I discovered that I pulled to one side a lot, so I had to adjust my form. In short, it took more effort than swimming in a pool and my blood sugar dropped faster. Cycling used a different set of muscles from swimming, and switching from one sport to another often burned calories faster than I would have expected. Finally, running a marathon when I had already been at it for eight or nine hours put me in an odd zone: I was more tired and stressed, which should have raised my blood sugar, but I was also more relaxed, which meant that I spend some of that time in a nice cardio zone where I was more insulin sensitive.

I got lucky. Things worked out.

Not long after that I found out from asking around that around 400 other Type 1s had done Ironmans. I made it my objective to get their names and invite them to a group. That group became the beginnings o the FB group Diabetic Ultra Endurance Athletes.

An ‘n’ of 1

In research, they often talk about sample size, usually referred to as N. The number represents the count of cases studied in the research. A small N usually indicates that either the study is preliminary or that there just weren’t enough subject to be found to create an organized study. Results are cautiously referred to as anecdotal, because a lot depends on the personal experiences of the few people available for study.

In 2014 and 2016, I had run the Texas Quad, which is four marathons on four consecutive days. A lot of people did the Texas Quad (around 30 each year), so I figured I’d use the Quad as a template for my upcoming 100-miler. In 2016, as I recall, I actually placed third overall in that event.

My first 100-miler in 2017 was nothing like that.

At the Honey Badger 100, one of the few “street ultras” I could find, conditions were challenging in a number of ways I didn’t anticipate. First of all, I kept running way too much of the time. At first I felt proud of myself as I passed some of the other runners. But as they sat down and took breaks, my pace slowed and the blisters built. By mile 50 and the first and only gas station on the route, not only did I REALLY need to use the bathroom; I also had full-foot blisters and desperately needed to tape my feet. The stress from the blisters sent my blood sugars up to above 300 mg/dl, and my repeated attempts to dose down my BG worked for no longer than it took for my body to suck up the glycogen it had dumped and then dump it again.

By the time a crazed farmer ran me off the road at mile 64, I could no longer feel my skin prickle from surges of adrenalin. I told my wife I was probably out of it. Finally, around mile 90, having shuffled all night through the darkness, high blood sugar and a really foul mood, I learned that the three runners that remained behind me had mostly dropped out. I was 2nd from last and flagging.

I decided to sit down and eat something. And magically, my blood sugar dropped.

Looking back, I’m certain it was the activation of my parasympathetic nervous system–the one that kicks in when the “cheetah stops chasing you”, that allowed me to actually absorb energy from food and start rebuilding glycogen stores. But whatever the science, my sugar dropped back down into the mid 200s, where I felt I could keep going.

It was a painful way to learn, but in my case and at that time, it was the only way, and I’m grateful.

It was an experience I’d see repeated across Iowa in 2018, Texas in 2019, and the US in 2020-2021. Each time I had to learn the hard way. I had to do my best to guess at what the experience was going to be like based on smaller efforts.

Catching fastballs

Prep for everything. But sometimes it pays off to practice everything that can go wrong, under controlled conditions.

When I did my first official marathon swim, a 10K (6.2 mi) swim half the distance around Key West in June of 2022 (I had trained to do the full 12 miles but estimated I couldn’t make the cutoffs), I took the same piecemeal approach: at a local lake, I’d swim the same 1.2 mile loop over and over again for as long as daylight would allow, starting at around 4 miles and working my way up to 8-10 miles, getting out to test my blood sugar every loop. This time, I wore a newly-obtained Garmin Fenix 6X Pro Solar that let me see my Dexcom blood sugar readings while swimming.

By time time of the Big Swim, I knew more or less when I needed to fuel and how much based on my starting blood sugar and level of effort, which depended on tides and weather. I realized that conditions might vary, so I had even deliberately gone out to the lake several occasions right after thunderstorms so I could get practice in high winds. On race day, the winds never came. Instead, the 30-minute starting time delay at Key West due to lengthy safety announcements drove my blood sugar above 300 mg/dl. Fortunately, that was a scenario I’d practiced dealing with when I was still getting my whey-shake-and-maple-syrup fuel mixture established during training swims.


There were some risks I felt comfortable taking in the lead-up to my USA run, and there were some I wasn’t so comfortable with. For instance, pushing the mileage into Odessa on Day 10 of my run across Texas nearly cost me a hospital stay or worse.

I look back on that day as both a learning experience–and a warning; as a reminder that the farther you stretch, the more you’re stepping out into the unknown.

After Texas, my immunologist recommended I try to keep the daily miles consistent as well as the frequency of rest days. I took his words to heart, and overall, the US run was a much more pleasant experience. Unlike Texas, during the US run, I didn’t have horrible low blood sugars, and I didn’t experience a recurrence of the bulging disc I had acquired at mile 700 running on cambered (slanted) roadsides and shoulders. I took better care of myself. I cut my average daily miles from 42 to 35 and was meticulous about getting carbs to replenish glycogen, protein to rebuild muscles, and enough sleep to allow those processes to work their magic. I put my pump in sleep mode most of the day, dialed my insulin back–15% at first, then as needed, and always got a slightly larger than average evening snack, as I knew the post-run highs following supper would come down on their own once the stress of running was gone.

All things being equal, the best strategy really is to eliminate unnecessary risks and reduce the necessary ones.

And if you can, write down the results when you don’t have a clue, test everything carefully and cautiously, and leave notes for the next guy. You never know who you’re helping.