Type 1 and triathlon

[marty313]

Last year, I documented in a series of posts how I, a 60-year-old type 1 diabetic, stepped up from triathlon sprint (750 m swim, 20 km bike, 5 km run) to olympic distance (twice the distance) (total time 3:01:40 s in Stavanger August 2023).

This year I did middle distance (1.9 km swim, 90 km bike, halvmaraton = 21.095 km).

Why double the distance? Twice the distance does not give twice the joy or satisfaction. However, when I swim 1.5 km or more in open water, I attain a flow state I which I become one with the elements and everything in my freestyle seems to fall into place. Wearing my open cell neoprene wetsuit (I live in Norway) I feel pretty much like a seal. I wanted to find out if I gain similar spiritual experiences in the other disciplines if I increase the distance. (It turned out: I do not.)

My triathlon mantra has been: I do nothing in a competition that I haven't practiced in my training. This applies especially to my diabetes management. So far, my mantra worked 100 %, on my first middle distance it didn't. I did indeed enter borderline terrain. Be warned: Middle distance is a completely different ballgame than Sprint and Olympic. To me it looks like it is not a good idea for type 1 diabetics, at least in my age group. In any case, you need to know precisely what you are doing. I happen to be a physician (not a diabetologist), but this was borderline terrain even for me. I open the discussion and invite your comments.

This is how I went about.

Originally, I had signed up for Challenge Sandefjord 70.3 middle distance triathlon on 24 Aug in Eastern Norway. The organisers let me freeze for 1.5 hours in my wetsuit before the 1.9 km swim in 16°C sea water in the harbour. I had taken a 5 min swim in the sea to warm up the water in my wetsuit, but over time it got cold. Then the competition was cancelled! All the while, my phone was in transition area 1 I had no readings from my Abbot Libre 3 CGM. (On 24 Aug I learnt: I now swim with my phone in a back pocket so that I get the readings all the time. This worked very well on Os Triathlon Sprint on 1 Sept. 2024.)
I was lucky in the event: They had put up an uncarpeted metal bridge over the coastal road with sharp metal edges that would have damaged my feet. (The trick: ignore the bridge, take the zebra pedestrian crossing and accept the 30 second time penalty!) A week later,
I did complete our local triathlon sprint on 1 Sept, but this did not clear my bucket list.

Since I was in the form of my life, I tried half ironman on my own last Saturday, 9 Sept 2024. The weather was perfect if not too warm (23 °C in the afternoon) but outdoor swimming conditions could not have been better! My goal was to reach the finish in good shape (regardless of the time). I kind of delivered.

Swimming went like a charm. 0:58:20 h. Pace 2:48 min/100 m. Cycling was OK, but the 200 m ascent to Fanafjellet after 65 km cost me. Total climb 1547 m. 4:17:34 h. Avg. 22.4 km/h 177 W not too bad. However, the halvmaraton off the bike went to my very limits. I had to walk on some of the ascents. I started thinking about the Saviour bearing the cross to Golgotha... (This was the nearest I touched upon a religious experience during the latter part of my triathlon - never had such thoughts during any run before!) I the end I left the Bergen Marathon course and chose flat terrain around Store Lungegårdsvann. I needed a rest in the shade every 4 - 5 km. When I walked or rested, i became dizzy and slighly nauseous. (Interesting: When I ran or rather shuffled along, I did not feel any such symptoms.) My halfmarathon time was 2:45:17 h (versus 2:06:40 h for Bergen Halfmarathon on 27 Apr 2024).

Total time 8:10:21 (versus 3:01:53 for olympic distance the year before).

Even though I had been drinking like a champion (2 l on the bike, 2 l on the run, 0.6 l after) I was 2.5 kg lighter than when I started. I recovered eventfully: No rhabdomyolysis, no arrhythmias (atrial fibrillation) in my post-excercise 12-h ECG (recorded with a Frontier II chest belt). The day after I cycled 22 km and swam 600 m without problems.

This is how I managed my diabetes. I use multiple daily injections with 13 IU Tresiba long-acting insulin at bedtime.
In the morning I ate 150 g AXA hazelnut muesli (= 90 g carbohydrates) with milk and natural yoghourt with 8 IU Novorapid. (I have come to prefer this particular muesli mix over AXA "Energy" muesli, which contains lots of raisins and give to high an intial blood sugar spike. ) I started my swim about 40 min later. Lowest temperature on my wrist was 17 °C, so I stipulate water was 15 °C.
I swam with an inflatable swim buoy, with my mobile phone inside. When I swim freestyle the Abbot Libre 3 sensor in the back of my upper arm is sufficiently long out of water so that my phone records my glucose - see attached bar diagram with my swim pace. I swam 4 1/2 laps of 220 m back and forth in my local lake, total 1939 m according to Garmin GPS. My peak gluose was 25 mmol/l at 20 min, I came out of the lake with 21.8 mmol/l. This is rather high. But in my training (I swam 1.8 - 2 km in open water once a week, my blood sugar at the end of the swim could be anything between 25 and 7. It was never lower than 7, but I don't want 6 or lower when I am in cold water and won't notice my hypoglucemia.)
Since my blood sugar was so high, I drank 500 ml of sugar free electrolyte solution on the first 20 km. When blood sugar was still stuck at 20 mmol/l 1:07 h into the ride, I finally injected 2 IU Novorapid. Then my blodsugar dropped to 7 at 2 h, but reached 4.7 at 3:15 h into the ride. From 2 h onward I drank 3 x 500 ml High 5 sports drink and ate 2 Fuel of Norway energy bars to keep my blood sugar above 7.
Each bottle contained 2 scoops of High 5 https://highfive.co.uk/products/energydrink = 44 g carbohydrates. The Fuel of Norway strawberry and chocolate bare contains 32 g of carbohydrates each. https://www.fuelofnorway.no/
In the last 3 hours of my ride I consumed 3 x 44 + 2 x 32 g = 196 g carbohydrates, that is 65 g/h.
I was struggling to keep my blood sugar up and I still had to do a halv marathon. So I munched 3 more such energy bars after transition 2 and I drank 1.5 l High 5 from the Camel Bak reservoir in my running vest. Despite all these measures, I barely managed to keep my bloodsugar above 7. At 1:50 h into the halfmarathon I was tired of High 5. Also the nausea in my walking pauses was making me nervous: was this beginning heat stroke (The sun was shining and I wore a cap) or was this ketoacidosis creeping in? I went into a local super market and bought 500 ml regular Coke to push my glucose up even more forcefully than with High 5. Norwegian Coke contains 10.6 g carbohydrates per 100 ml. So, during 2:45 run h I consumed 3 x 44 + 3 x 32 + 1 x 53 g = 281 g carbohydrates which about 100 g/h and pretty close to the physiological limit.

Pushing glucose up with Coke had the intended effect that I was able inject a 5 IU bolus of Novorapid at a blood sugar of 9.7 when I was across the finish line to fight ketoacidosis. I bought and drank another 500 ml Coke to guard against hypoglycemia.

I took tram and bus home and arrived there about 30 min later. I had last emptied my bladder aftert the swim and then 2 1/2 h into the bike ride. I only produced about 300 ml and the urinary test revealed traces of ketones. (I had tested urinary ketones on about 50 occaisions when I was using Forxiga 3 years ago and NEVER had ketones in my urine no matter if before or after training.) When I weighed myself before the shower I had lost 2.5 km against my weight before breakfast.

My conclusion:
Even if you train consistently and in high volume months ahead, middle distance is a whole different animal than Sprint or Olympic. My golden principle has been: In a competition, I do exactly as I have trained. This worked extremely well in all my previous triathlons, Sprint and Olympic, and in 3 halfmarathons. NOT HERE! Despite training very hard over the entire season (typical week total 5 km swimming, 100 km cycling, long rides in the 3 months before, 15 - 25 km running, 15 km since July due to achilles tendinitis) the halvmarathon pushed me into uncharted terrain, including possible borderline ketoacidosis. If you do this in a mass event and get carried along by the others, this can be positively dangerous. Be warned!

 

[Antje77]

It's lovely to see you again, @marty313 , and with such an interesting experience too! Even if it didn't go perfectly, you still managed.

Not the same at all where it comes to endurance and physical effects (I'm still mostly a couch potato, even though I do a short swim every day) but I had my own experiment and challenge last sunday: My daily swims hadn't lasted over 25 minutes so far, which is how long I'm very sure I can safely swim in about 20 °C water, I start dropping at 35-45 minutes in so I can do those swims without anything on me, just me and the water (and the occasional surprised passer by).
But rounding the corner of my canal, I could see the big blue pump house in the distance, and every day I wanted to go there and couldn't. Too dangerous, too far, not with T1, not alone in the middle of nowhere.

Until I decided I could, with the right precautions, and I had to move quick before the water temperature dropped and it would truly be impossible until next summer. Google maps told me the distance was about a nautical mile, maybe 3 times the longest distance I'd swum outside or a little more, definitely doable.
Donut type tow float with room to take my gear, parked my car close to the exit point, left my dressing gown right next to the exit point (crucial, I went with only my tow float and nothing else so I would have made quite a sight walking back to my car), and had a friend drop me off at the staring point.

Mind, it wasn't a physical challenge at all except for dealing with diabetes, so completely different from your experience. But it definitely was a win on diabetes, doing this on my own without knowing how diabetes would react.
It took me an hour and 40 minutes, swimming leisurely but firmly (I have an inkling the distance was a little more than 1.852 kilometers). Glucose checks were a hassle and took a long time, drying hands and juggling stuff on the buoy making sure to keep everything dry, my sensor was useless.

But it turned out to be perfectly possible!
And just in time too, on sunday the water was still around 20 °C, yesterday it had dropped to 16 and I suppose it was even colder today so it's only short swims from now on until next summer.

 

[marty313]

I am very impressed by your swimming.
In my opinion, skinny dipping in open water is the only real way to swim. It is kind of accepted in Germany (my native country), somewhat but less so in Norway but in my experience from 1984, risky in Britain. Too bad!

The major risk to be aware of is hypothermia. It is positively dangerous. It only takes 5 min in really cold water and you don't care anymore. I have a near drowning experience when I trained reentering my sea kayak. After the 4th failed attempt it took me all my willpower to make it into my kayak. And this was 10 m from land!

The other aspect is that cold leads to adrenergic stimulation - the same feeling that I get when I get critically hypoglycaemic.

So I always swim with a wetsuit. Please be aware that swimming wetsuits from soft and pliable neoprene cost € 300 +. You only find them in specialist shops and you need to try them on. They need to sit like a second skin. As a reward you will feel like a seal.

I am privileged that Norway pays for my Abbot Libre 3 CGM. The hardware is top, the software is c..p! I want my glucose on my sportswatch.
Abbot earned pots of money of selling the already obsolete Abbot Libre 2 sensor to top athletes like Big Blu from Bergen (Kristian Blummenfelt) bundled with software that just did that!
The Libre 3 is worn on the fleshy back (or side) of the upper arm. If you keep your phone in your swim buoy, it will send the values to my Garmin Forerunner 955 on my wrist where I get my current glucose on my exercise watch face. How you do this with Juggluco I wrote in a separate post.

Without Juggluco and online glucose on my watch I would not have stood a chance of completing my half ironman!

 

[SimonP78]

Echoing @Antje77, nice to see you back @marty313

When blood sugar was still stuck at 20 mmol/l 1:07 h into the ride, I finally injected 2 IU Novorapid. Then my blodsugar dropped to 7 at 2 h, but reached 4.7 at 3:15 h into the ride. From 2 h onward I drank 3 x 500 ml High 5 sports drink and ate 2 Fuel of Norway energy bars to keep my blood sugar above 7.
Each bottle contained 2 scoops of High 5 https://highfive.co.uk/products/energydrink = 44 g carbohydrates. The Fuel of Norway strawberry and chocolate bare contains 32 g of carbohydrates each. https://www.fuelofnorway.no/
In the last 3 hours of my ride I consumed 3 x 44 + 2 x 32 g = 196 g carbohydrates, that is 65 g/h.
I was struggling to keep my blood sugar up and I still had to do a halv marathon. So I munched 3 more such energy bars after transition 2 and I drank 1.5 l High 5 from the Camel Bak reservoir in my running vest. Despite all these measures, I barely managed to keep my bloodsugar above 7. At 1:50 h into the halfmarathon I was tired of High 5. Also the nausea in my walking pauses was making me nervous: was this beginning heat stroke (The sun was shining and I wore a cap) or was this ketoacidosis creeping in? I went into a local super market and bought 500 ml regular Coke to push my glucose up even more forcefully than with High 5. Norwegian Coke contains 10.6 g carbohydrates per 100 ml. So, during 2:45 run h I consumed 3 x 44 + 3 x 32 + 1 x 53 g = 281 g carbohydrates which about 100 g/h and pretty close to the physiological limit.

I sometimes run very high at the start of long rides - dawn effect and nerves and small breakfast with insufficient bolus to deal with everything. I don't generally want too much IoB having experienced the eating requirements of you talk about. However, I think I just need to accept that early in a ride I am still willing and able to eat, so I should err on the side of more bolus to reduce the spike and avoid needing to take a correction later in the ride. This is obviously not going to work for you with the swimming, but my comment is that I've also tried taking correction doses, and I find that I only need 0.5 to 1.0U of bolus to generate a massive rate of change of BG and I then need to start eating ~40-60g/hr once down into range (or ideally have lunch, again not suitable for racing!) I'd perhaps be tempted to inject less correction.

I have also had rides where I had to eat continuously from about half way around, either very early on in my riding career because I'd not realised I should reduce basal, or slightly more recently because I'd foolishly stopped for too long for lunch and decided to inject some bolus. It feels terrible, for me at least, to need to force down the quantities of carbs that are necessary to avoid going hypo. It's probably also not great for how one feels to be bumping along just above hypo for hours at a time. I can quite understand how it was very difficult to do the run under these conditions (I remember the stop for a break, let the nausea subside, eat more, keep going thing well), so well done for making it round.

Pushing glucose up with Coke had the intended effect that I was able inject a 5 IU bolus of Novorapid at a blood sugar of 9.7 when I was across the finish line to fight ketoacidosis. I bought and drank another 500 ml Coke to guard against hypoglycemia.

I took tram and bus home and arrived there about 30 min later. I had last emptied my bladder aftert the swim and then 2 1/2 h into the bike ride. I only produced about 300 ml and the urinary test revealed traces of ketones. (I had tested urinary ketones on about 50 occaisions when I was using Forxiga 3 years ago and NEVER had ketones in my urine no matter if before or after training.) When I weighed myself before the shower I had lost 2.5 km against my weight before breakfast.

Why are you concerned about ketoacidosis - could the trace in your urine be because you were underfuelled and were burning fat? Or did you not have any basal on board?

I've always believed that as long as I have some background basal (I typically take typically half of my usual morning dose, with the previous evening's full dose still active too) I don't need to worry about ketoacidosis, even if I run high at the start and don't eating enough carbs to cover the full calorie burn (sp am being at least partially fueled via fat->ketones.) I always have a calorie deficit when riding as I just don't like consuming the same quantity of calories I'm burning while on the bike.

I got a ketone test meter to see what effect long distance riding has, and the last 200km ride I did when I remembered to test when I got home produced a ketone reading of 2.3mmol/l (4h after the ride so I see in another thread on here about ketones.) I felt fine that day and evening and did a 100km ride the following day iirc so presumably felt pretty reasonable in general. I don't know off-hand what blood concentration produces ketones in the urine but I wonder if this is actually a thing you need to worry about? I would definitely get a ketone blood test meter (we can get them free in the UK if type 1 diabetic, it may be different for you and only urine strips are available?) I'll do some Googling to see what blood concentration produces urine spillover and post a comment with what I find.

 

[Antje77]

Thanks for your informative post @marty313 .

I'm not sure how accepted skinny dipping is in the Netherlands, but so far no-one has complained, and few people have spotted me anyway. Last week there were two men throwing a ball in the water for their dog right where I wanted to get in, and I had forgotten to bring a swimming suit for just such a situation. So I put on my dressing gown, walked to the water, pet the dog, and told the men they could kindly turn around while I entered the water. No idea if they did but they did laugh so I guess they didn't mind.

As for wetsuits, no thanks. I'd much rather adjust the length of my swims, last winter I swam once a week, and at the coldest point (having to break ice) it was maybe two or three minutes, works for me.

Please be aware that your Libre will likely be useless when the water gets colder. The Libre2 will only give you a 'Sensor too cold' message if you try to scan it, I had the first of those yesterday.
Not sure what the 3 will do, but I wouldn't count on it in cold water!

 

[marty313]

Thanks for your informative post @marty313 .

I'm not sure how accepted skinny dipping is in the Netherlands, but so far no-one has complained, and few people have spotted me anyway. Last week there were two men throwing a ball in the water for their dog right where I wanted to get in, and I had forgotten to bring a swimming suit for just such a situation. So I put on my dressing gown, walked to the water, pet the dog, and told the men they could kindly turn around while I entered the water. No idea if they did but they did laugh so I guess they didn't mind.

I should have guessed that you were Dutch...

As for wetsuits, no thanks. I'd much rather adjust the length of my swims, last winter I swam once a week, and at the coldest point (having to break ice) it was maybe two or three minutes, works for me.

The point I was trying to make: A triathlon wet suit made from pliable neoprene feels like a second skin. I usually start by swimming 50 m breast and then return swimming freestyle so that water seeps into the arms. Then I get on land so that the water traverses the entire suit. After the remaining water is warmed up a good well-fitting wetsuit feels quite pleasant. Don't try cheap wetsuits designed for surfing. Dry suits for padding are also different. Before I went deep into swimming in January 2019, I was into sea paddling. I rolled my kayak even when I had to break ice (it is only 4 C below the ice), but I do not relish the experience.

Please be aware that your Libre will likely be useless when the water gets colder. The Libre2 will only give you a 'Sensor too cold' message if you try to scan it, I had the first of those yesterday.
Not sure what the 3 will do, but I wouldn't count on it in cold water!

As you point out, the Libre 2 needs to be scanned in order to get measurements (only alarms are transmitted via Bluetooth). A Libre 3 is smaller and sends all measurements via Bluetooth every 5th minute. Scanning is only needed for starting the sensor and pairing.

I cannot remember a "Sensor too cold" error with my Libre 3, but then I wear it UNDER my wetsuit. (In order not to rip it off, I first put in my sensor arm. When I undress, I start with the non-sensor arm, taking out the sensor arm last.)
I documented in a different thread that the Abbot Libre 3 Android phone software is pretty useless: No android widget showing glucose on home or lock screen, and - worse - no way to attach a Garmin watch such as my Forerunner 955 S to the software on the phone. You need to use a Abbot Libre Link account so that xDrip can read the data from the Abbot server in the Internet. Not only does this strain your mobile data bill, it eats the phone's battery and loses touch with the sensor 20 % of the time. The sensor software is bloody useless. I gave them 1 star in Google Play Store and they responded every time that I should ring support! I now switched to Juggluco. It works like a charm, but of course it is not supported by Abbot - you do it on your own responsibility. I think that I can get my glucose on my Garmin watch under long swims, but this requires that the phone is in a swim buoy above water (which is not competetition legal!) and I need to do some more testing. As the Norwegian lakes are getting cold now I will report in summer 2025.

 

[marty313]

I sometimes run very high at the start of long rides - dawn effect and nerves and small breakfast with insufficient bolus to deal with everything. I don't generally want too much IoB having experienced the eating requirements of you talk about. However, I think I just need to accept that early in a ride I am still willing and able to eat, so I should err on the side of more bolus to reduce the spike and avoid needing to take a correction later in the ride. This is obviously not going to work for you with the swimming, but my comment is that I've also tried taking correction doses, and I find that I only need 0.5 to 1.0U of bolus to generate a massive rate of change of BG and I then need to start eating ~40-60g/hr once down into range (or ideally have lunch, again not suitable for racing!) I'd perhaps be tempted to inject less correction.

It is reassuring to read that you experience the same issues when exercising. Since I often start with a 50 min swim (shorter if the water is only 14°C, I have a Garmin Tempe in order to measure 60 cm below the surface in accordance with official triathlon rules) I have my standard 150g AXA hazelnut muesli load + 8 IU Novorapid insulin. I never came out of the water with less than 6, but sometimes with 20+. Therefore I now carry 500 ml saline mix less carbohydrates but also 3 x 500 ml High 5.
When injecting insulin during the bike ride the effect of just 2 IU can be humongous- I was struggling to keep my glucose above 6 the rest of my ride and run. I should have injected just 1.5.

I have also had rides where I had to eat continuously from about half way around, either very early on in my riding career because I'd not realised I should reduce basal, or slightly more recently because I'd foolishly stopped for too long for lunch and decided to inject some bolus. It feels terrible, for me at least, to need to force down the quantities of carbs that are necessary to avoid going hypo.

I agree!

It's probably also not great for how one feels to be bumping along just above hypo for hours at a time. I can quite understand how it was very difficult to do the run under these conditions (I remember the stop for a break, let the nausea subside, eat more, keep going thing well), so well done for making it round.

Exactly!

Why are you concerned about ketoacidosis - could the trace in your urine be because you were underfuelled and were burning fat? Or did you not have any basal on board?

I inject 13 IU Tresiba at bedtime every day. No reduction for exercise, but I exercise every day.

I've always believed that as long as I have some background basal (I typically take typically half of my usual morning dose, with the previous evening's full dose still active too) I don't need to worry about ketoacidosis, even if I run high at the start and don't eating enough carbs to cover the full calorie burn (sp am being at least partially fueled via fat->ketones.) I always have a calorie deficit when riding as I just don't like consuming the same quantity of calories I'm burning while on the bike.

You may be right. It may be that I am just paranoid. It would be different I exercised with a pump. The catheter may be blocked or dislodged.

I got a ketone test meter to see what effect long distance riding has, and the last 200km ride I did when I remembered to test when I got home produced a ketone reading of 2.3mmol/l (4h after the ride so I see in another thread on here about ketones.) I felt fine that day and evening and did a 100km ride the following day iirc so presumably felt pretty reasonable in general. I don't know off-hand what blood concentration produces ketones in the urine but I wonder if this is actually a thing you need to worry about? I would definitely get a ketone blood test meter (we can get them free in the UK if type 1 diabetic, it may be different for you and only urine strips are available?) I'll do some Googling to see what blood concentration produces urine spillover and post a comment with what I find.

In Norway, you only get sticks for urinary measurements. I have a meter for blood measurements, but the strips that I ordered last year were already expired when I received them!
Measuring urine has the advantage that you even catch recent ketoacidosis even after the event (assuming that my bolus on the finish line had fixed my metabolism by the time I was back home).

 

[marty313]

I should have guessed that you were Dutch...

This is actually quite interesting: Why are you and I active on the British diabetes forum?

The reason for me: I never found a similarly enlightened and stimulating diabetes forum anywhere else! This is the only forum in which I can meet hardcore endurance athletes with diabetes type 1 or 2. This forum has helped me preparing for my half ironman - all the feedback and questions I received on my posts regarding lactate testing and olympic triathlon (which I had posted in a dedicated thread on lactate testing last year) helped me in my understanding diabetes management during endurance exercise. Without the moral support that I received on diabetes.co.uk I probably would not have managed.

 

[Antje77]

I should have guessed that you were Dutch...

I'll be visiting the UK for two weeks of camping in October and I have a feeling I'd best bring more than one swimming suit if I don't want to get in trouble and don't want to put on a wet swimming suit before it had a chance to dry...
Or I'll just be the stupid tourist of course, not knowing any better and speaking 'English' as incomprehensible as the average Dutch football trainer.

A triathlon wet suit made from pliable neoprene feels like a second skin. I usually start by swimming 50 m breast and then return swimming freestyle so that water seeps into the arms. Then I get on land so that the water traverses the entire suit. After the remaining water is warmed up a good well-fitting wetsuit feels quite pleasant.

Sounds perfect if you want to do longer swims, and an absolute must for triathlon.
But while it may feel very good once it's on, you still have to put it on and peel yourself out of it afterwards. Very different from quickly taking off your clothes and getting into the water or donning a dressing gown after before driving home again. I absolutely hate tight fitting clothing too, so even the thought of a wetsuit makes me shiver. Much more expensive than skinny dipping too!

As you point out, the Libre 2 needs to be scanned in order to get measurements (only alarms are transmitted via Bluetooth). A Libre 3 is smaller and sends all measurements via Bluetooth every 5th minute. Scanning is only needed for starting the sensor and pairing.

I cannot remember a "Sensor too cold" error with my Libre 3, but then I wear it UNDER my wetsuit.

I use Libre 2 both with the original app and scanning (I like it for logging my insulin), and with DiaBox, which uses bluetooth and gives me my numbers directly on my phone, no need for scanning.
DiaBox gives a sensor error when the sensor is too cold so I wouldn't count on Libre 3 to keep working.
Wearing it under your wetsuit may just make the difference though.

 

[Antje77]

Measuring urine has the advantage that you even catch recent ketoacidosis even after the event (assuming that my bolus on the finish line had fixed my metabolism by the time I was back home).

You can catch ketosis after the event with pee sticks, but this doesn't say anything about ketoacidosis.
I'm not familiar with exercise induced ketosis or ketoacidosis, but the two situations are completely different, with one being deadly if untreated, and the other just meaning you're burning fat instead of glucose for fuel.
A significant portion of our members (mostly the T2's) are in ketosis and are producing ketones most of the time.

I have no idea if I'm regularly in ketosis or not, I don't own pee or blood sticks to test, and I don't really care if I am or not.
I might well be, I eat little carbs and often don't eat until the afternoon.

When I did my long (for me) swim, I went fasted (except for coffee of course, with a splash of milk) so I didn't have any active insulin on board. I already experienced that a swim can make my insulin work much faster so going without IOB seemed best. I did have my usual dose of Tresiba before bed.

I usually take a small dose of insulin for Foot on the Floor, but on this day I skipped, counting on this liver dump to safely see me through the first half of my swim. Which meant I started at around 9 mmol/l, higher than I like but on this day it gave me a nice safety buffer.
At 40 minutes in I had a quarter of a small apple because I was execting a drop soon. Some 35 minutes after that I tested at 5.9, and I swum the rest without more carbs, finishing at 4.3 after an hour and 40 minutes. So I should have a little more of the apple to be on the safe side, but no spectacular ups and downs like I would have had with insulin and extra carbs on board.

No idea how this would translate to the much more extreme exercise you are doing though.

 

[Antje77]

This is actually quite interesting: Why are you and I active on the British diabetes forum?

The reason for me: I never found a similarly enlightened and stimulating diabetes forum anywhere else!

This of course!

And the general feeling of patience and understanding on this forum, no matter what situation anyone is in.

 

[SimonP78]

I now switched to Juggluco. It works like a charm, but of course it is not supported by Abbot - you do it on your own responsibility. I think that I can get my glucose on my Garmin watch under long swims, but this requires that the phone is in a swim buoy above water (which is not competetition legal!) and I need to do some more testing. As the Norwegian lakes are getting cold now I will report in summer 2025.

Completely agree with the choice of using Juggluco + XDrip+. You can also enable 1 minute readings in XDrip+ (at least on the libre2, I assume the libre3 does the same) which then shows the 1min data (little white dots) from the sensor alongside the 5min averaged (red) data that XDrip+ calculates from the input.

The other option that might be of interest is to run Jugguco on an Android watch and use it as the collector as well as the display (i.e. no phone required). There are details on the Juggluco website (as well as some threads on this forum.) I've no idea whether it would work when swimming though as both the shoulder and watch may not be above water at the same time/for long enough/etc.

I wonder if it's possible to get a competition medical waiver to allow the use of a swim buoy?

 

[marty313]

Completely agree with the choice of using Juggluco + XDrip+. You can also enable 1 minute readings in XDrip+ (at least on the libre2, I assume the libre3 does the same) which then shows the 1min data (little white dots) from the sensor alongside the 5min averaged (red) data that XDrip+ calculates from the input.

The other option that might be of interest is to run Jugguco on an Android watch and use it as the collector as well as the display (i.e. no phone required). There are details on the Juggluco website (as well as some threads on this forum.) I've no idea whether it would work when swimming though as both the shoulder and watch may not be above water at the same time/for long enough/etc.

I wonder if it's possible to get a competition medical waiver to allow the use of a swim buoy?

I pair Juggluco with my sensor. xDrip+ is not needed, but you need special plugins on your Garmin watch or your Garmin cycle computer (I detailed which ones work in a separate post). I am aware that Juggluco supports pairing the sensor directly with an Android smartwatch. 3 years ago this would have been my dream, now I am kind of brainwashed by Garmin and all their sensors (Garmin HRM Pro+ pulse belt, Garmin Keo power pedals on both my racing bikes, Garmin smart scales, Garmin Tempe thermometer; Garmin Forerunner 955S, Garmin Edge 530 bike computer) that I stick to Garmin on all fronts.
You are right - there are reasons to believe that an Android watch (at least if worn on the opposite arm) and the sensor may become unpaired when swimming freestyle.
I am used to writing the technical director of each triathlon that I need my mobile phone. Challenge Sandefjord 2024 demanded a statement from my diabetologist. Before requesting a swimbag I would prefer to have swim socks as I am mortally afraid of cutting my feet during the swim start and the run to transition 1. I was lucky Challenge Sandefjord was cancelled (unfortunately 1 hour after scheduled start - I was freezing in my wetsuit) - they had a foodbridge with bare metal steps designed to prevent workmen's shoes from slipping. (In such case: bypass the bridge and accept a time penalty.)

 

[marty313]

This of course!

And the general feeling of patience and understanding on this forum, no matter what situation anyone is in.

Exactly. This forum gave me all the mental support that I needed when I went down the rabbit hole called "triathlon". I think that triathlon helped me towards a healthier lifestyle. At a body weight of 102 kg (+), I was developing insulin resistance on top of my DM T1. Now I maintain my weight at around 90 km (at 183 cm), and my insulin resistance is under control.

 

[SimonP78]

I pair Juggluco with my sensor. xDrip+ is not needed, but you need special plugins on your Garmin watch or your Garmin cycle computer (I detailed which ones work in a separate post).

I just prefer the integrated carbs/insulin/CGM display and predictions that XDrip+ provides to the interface of Juggluco.

I note Juggluco can emulate the XDrip+ http server which is used by Garmin ConnectIQ plugins/watch faces, so as you say (for anyone else reading) XDrip+ itself is not necessary to pair with a Garmin device.

 

[marty313]

I just prefer the integrated carbs/insulin/CGM display and predictions that XDrip+ provides to the interface of Juggluco.

I note Juggluco can emulate the XDrip+ http server which is used by Garmin ConnectIQ plugins/watch faces, so as you say (for anyone else reading) XDrip+ itself is not necessary to pair with a Garmin device.

I agree that the glucose predictions are a very useful feature of xDrip, which is lacking in Juggluco. On the other hand, Juggluco has a very detailed food database, which I find very useful.

To get glucose on your Garmin watch yuo can either (1) pair xDrip with an Abbot Libre Link account and download values from the Abbot cloud. This requires mobile data/Internet access on your mobile, eats a lot of battery (more than a half ironman will require) and only works 80 % of the time. Sometimes I got glucose on my watch before the swim but not during the bike leg when doing a triathlon. Or (2) you pair Juggluco with your Libre 2 or 3 sensor. You can then set up a local Juggluco Nightscout server and use xDrip to display your data.

 

[marty313]

Last year, I documented in a series of posts how I, a 60-year-old type 1 diabetic, stepped up from triathlon sprint (750 m swim, 20 km bike, 5 km run) to olympic distance (twice the distance) (total time 3:01:40 s in Stavanger August 2023).

This year I did middle distance (1.9 km swim, 90 km bike, halvmaraton = 21.095 km).

... If you do this in a mass event and get carried along by the others, this can be positively dangerous. Be warned!

A colleague alerted me to the following scientifc paper that is indexed on PubMed:
https://pubmed.ncbi.nlm.nih.gov/36647854/

Weiss K, Thuany M, Scheer V, Ouerghi N, Andrade MS, Nikolaidis PT, et al. How to end up on the podium after running a 6-days-run with type 1 diabetes mellitus - A case study and literature review. Eur Rev Med Pharmacol Sci. januar 2023;27(1):88–97.
Free full text under https://www.europeanreview.org/article/30856

On principle grounds I am not fond of case reports - ideally one should have a case series. Only 90 % that I observe in medicine (I am a nuclear physician with a special interest in thyroid, parathyroid and neuro) is "logical" - at least 10 % of my observations I cannot quite explain in terms of common wisdom/published evidence. So n = 1 patient (be it myself or a case report) does not get you very far. In my clinical experience, I need 20 patients with a given condition in order to see patterns and gain a more intuitive understanding.
But: The review part of the article is quite good: there is a growing number of athletes with diabetes type 1 that perform endurance sports including full distance ironman at a very high level. You will find them in the reference list of this article as well as under the PubMed link.