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2023 T1Deca (10X Iron) Triathlon Challenge

Start Date: October 2023

24 miles swimming, 1120 miles cycling, 262 miles running

In October 2023 I plan to challenge myself to do the equivalent of 10 full-iron distance (140.6) triathlons in a row.

I've been lucky to do some amazing things, but every challenge is new. My goal, as always: discovering what a 62-year-old Type 1 diabetic can do, and sharing the lessons learned.

It can be scary for folks like me, with Type 1 diabetes, to exercise. Exercise drops blood sugar, and the fears of severe overnight low blood sugars and dying in your sleep are real and justified. And yet, you have to do something. For 32 years I let my fear of lows take control and suffered the consequences. I still have a blind spot in my left eye to remind me about the road I almost took.

Learning from others is so much easier than learning from consequences. It's my fervent hope that something I learn will help others like me find their own best way to be active.

Don - Water Bottle

Stuff I Get Asked

Will you be doing this all at once? If not, how exactly will you do this?

If you mean without sleep, no.

I know some folks do events like this with minimal sleep, but my experience is that the best way to blow up my blood sugar control is to get as little sleep as possible.

My experience has also been that my decision-making about insulin dosing, fueling and other aspects of diabetes management suffers if I shortchange my sleep too much.

This time of year I'll have about 12 hours of daylight, so my plan is start shortly before first light, and end shortly after last light.

I have a day job, so I'll be squeezing work commitments into the periods when I'm not swimming, riding or running.


I plan to do the 24-mile swim as 3 days of 8 miles/day.

JFYI, if I were to do the swim as open-water, I'd most likely fuel near or on shore periodically, probably every 2 miles or so. It's not a USA Swimming or Marathon Swimmers Federation-sanctioned event, so I wouldn't officiallly be bound by no-contact-with-the-boat and no-flotation-assistance rules. Nonetheless, I wouldn't touch my support kayak or receive forward assistance from any outside source.

If I were to do the swim in a pool, I'd check my blood sugar and fuel and hydrate  about every two miles as well.

In open water, I'd also use a bright orange visibility buoy with a dry bag containing my cell phone so my Dexcom transmitter could send blood glucose numbers to my Garmin watch, but I wouldn't use it for flotation assistance.


My goal is to ride the full Iron distance every day, for 10 days, on bike friendly streets and local bike paths.

If the weather cooperates, who knows, I might even go over 112/day. 

If it doesn't, I might cover somewhat fewer miles and take a bit longer. When I ride on extremely hot days, I can literally see my blood sugar rise. 


I plan on logging a little over 50 kilometers a day (33 miles or so)  for 8 days.

Where will this take place?

I'll do all three sports in the Dallas-Fort Worth area.

How long will this take?

About 3 weeks, including likely weather delays (no swimming, riding or running in lightning or thunderstorms, folks!) and a couple of rest days.

I have a day job, so when I'm not swimming, riding, running, sleeping or eating—I'll be working.

How do you stay on top of your blood sugars?

The two-word answer is: Very Carefully.

First, I use the Garmin-Dexcom integration, which is Dexcom's officially-approved way to view blood sugars on Garmin watches like my Fenix. They partnered with Garmin on this integration, so it's a significant step up from third-party apps like xDrip and Nightscout that require GitHub downloads, builds, and connecting up multiple apps and servers by hand.

For swimming specifically, I've found that the integration works best when the Dexcom CGM transmitter is near, at, or above the surface of the water and I'm using a normal swim stroke that gets the watch out of the water enough to receive a reading.

When I swim in open water, I always use a visibility buoy. It has a built-in sealable dry sack, so I put my phone in a drybag inside the dry storage in the buoy. If the system doesn't pick up a reading, it typically buffers it on the transmitter until it can send one to the phone, which shares it with the watch.

It's hard to tell in cold water if you are sweating or feel shaky, so I look for clues like a sudden degradation in my swimming technique, clenched jaw, or a feeling of doom and gloom; and when in doubt, I get carbs.

Second, I train consistently so I know what my blood sugar needs to be when I start swimming, riding or running, and I know how many carbs to get, and how often, to avoid going too low or too high. 

Third, I stick to a very detailed fueling plan before and after the day's event. This is absolutely crucial for anyone with Type 1 diabetes.

I have learned the very hard way that missing fueling breaks during intense multi-week events is a recipe for a very severe low blood sugar.

We keep track of all the fueling stops to make absolutely sure I stay on track. One thing we've learned is that you absolutely cannot skip fueling breaks, because you're burning calories so fast that you can't catch back up. 

Can I stop by and say "hi"?

Sure you can! I love company.

Shortly before I start the T1Deca, I'll post the swim location.

For the bike, feel free to ride with me. If you can keep a "social ride" pace of around 10 mph and you're willing to stop for blood sugar checks and fuel breaks, you'll fit right in. 

I'll post the run route right before the event starts. 

The one thing I won't be able to do is STOP and talk during the actual event; it already takes most of the day. If we need to chat,  let's set a time to do that after I finish the T1Deca.

I want to follow you remotely. How do I do that?

During the event day, I will have a Garmin InReach satellite tracking beacon. We'll post a tracking link on the main page.

Do you need anything? How can I support you?

What I really value most, as corny as it sounds, is your faith in the indomitable human spirit and your own ability to handle what T1D throws at you or your loved ones. If you took that home and bottled it, then paid it forward, I'd feel like I'd accomplished my goal,

That said, I'm self-funded, so contributions to me directly are always appreciated.

My ultimate dream is to provide a free, practical source of information for people struggling with how to balance diabetes and exercise--to close that last mile between "You're diabetic" and "How will I ever do anything active again?" In the mean time, though, we can help each other.

Right now, you can point people to one or all of these Facebook groups: Type 1 Diabetic Athletes, TypeOneRun and its many local chapters, the local chapters of my own Diabetes & Exercise Alliance, and the Diabetic Ultra Endurance Athletes Facebook group. There are many more, around the world, but these will get anyone with T1  looking for their tribe off to a good start.

You can also support one of these non-profits that help us thrive, fight discrimination, and look for better treatment and cures.