10 Tips To Successfully Run Your First Marathon With Type 1 Diabetes

Running a marathon with type 1 diabetes (T1D) is more than just tracking miles. You’ll do the same training as everyone else—long runs, tired leg days and a taper that leaves you restless. What’s different is what’s happening in your bloodstream the whole time! Yep, that beautiful flow of insulin you have to administer and manage yourself.

When you run a marathon with T1D, your blood sugar may climb, drop, then climb again over hours of effort. No generic training plan addresses that, so you’re the one who has to build that part of your training program—but you don’t have to do it alone! In fact, you’re encouraged not to, especially if it’s your first time. No two runners manage T1D the same way, either, and that’s okay—it’s why customized training plans are so vital for runners with an unrelenting chronic illness like T1D.

Beyond Type Run, Beyond Type 1’s own marathon team, has worked with runners with T1D for years, and one thing remains true—the plan that helps on race day is the one you tested first. In this guide, we share practical tips and advice to help you build your ideal training plan and conquer each mile with confidence and safety!

1. Start your training on the right foot

Running your first marathon with T1D can feel exciting but daunting. If you’re just getting started, here are some ways to successfully lay your groundwork so your mind and body are prepared:

• Alternate running and walking during training: do this instead of trying to run the whole distance start to finish. It’s easier on your body and your blood sugar. Maybe even your knees, too!
  
• Don’t panic if you miss a training goal: plenty of first-time marathoners never complete a full 26-mile run before race day, and they still cross the finish line. It takes practice, just like most things in life. This skill takes time and persistence to build. Becoming a good runner quite literally requires endurance and staying the course.
  
• Don’t fall for the comparison trap: seeing someone else’s longer training log on social media or a group fitness app doesn’t say anything about your own progress, nor do their blood sugar levels during it. Everyone’s schedule and blood sugar patterns are different. How your body responds to marathon training can be completely different than someone else’s! Pay attention to how you feel and how your blood sugar is impacted during training, not how someone else feels in a body that isn’t yours to manage.
  
• Pay attention to how different runs influence your blood sugar levels: short, fast runs tend to raise blood sugar, while long, slow runs tend to bring it down steadily. Of course, this is a general rule of thumb. Don’t panic if something different happens to you. Be aware and bring your learnings forward to your team (healthcare or marathon) so you can troubleshoot together. Knowing your numbers will help you make decisions about how to approach your next run.
  
• Learn your blood sugar patterns over weeks, not one run: this helps you identify and plan your fuel and insulin needs for race day. Gather data over weeks, not a single day. Otherwise, they’re not really patterns.

2. Plan your marathon with your healthcare team

Meet with your care team consistently during training, more than once before race day. Ask for help figuring out how much to lower your basal (long-acting) insulin for race day, and how to bolus for your pre-race meal and any carbs you eat mid-run. Even if you’re confident in your adjustments, at least throw the numbers their way for input! Even strong self-managers need team input.

An international team of exercise and endocrinology experts has published consensus guidelines for safe exercise with T1D, covering exactly this kind of insulin and blood sugar planning. Use it as much as it helps you!

Talk through a backup plan for if your continuous glucose monitor (CGM) stops working. And ask your team when you should be checking for ketones if your blood sugar runs high during the race—that’s not a conversation you want to have for the first time at mile 18. Both can happen pretty easily!

3. Get ready the week before

Pack your race bag a few days ahead, not the night before, when you’re tired and rushing. Plan to get a good night’s sleep and keep things consistent the night before. Predictability helps with blood sugar stability and supports a good night’s sleep. Don’t spend the night before partying—that’s what crossing the finish line is for!

Include these diabetes supplies in your race day pack:

• Backup CGM sensors
• A blood sugar meter (BGM)
• Fast-acting sugar for lows
• Snacks for nourishment
• Extra clothing
• Medical identification (ID)

4. Set realistic expectations and protect your diabetes supplies

Expect the start area of the race to be cold and slow. Plenty of marathons hold runners in a corral for an hour or more before the gun goes off, so bring warm layers you’re fine with throwing away, plus extra snacks to eat while you wait. 

Keep your devices and insulin temperature stable. Cold weather can make a meter read wrong or stop working altogether, so carry it in an inner pocket close to your body instead of an outer bag pocket. Try to take each step as it comes rather than mapping every detail weeks in advance, since that just adds stress you don’t need. Take it one task at a time from bib pickup to bag packing to getting to the start line.

5. Consider investing in T1D-friendly marathon gear

You don’t have to jam your pump, CGM supplies and low blood sugar treatments into whatever pockets your running shorts happen to have. 

A few marathon heart options built specifically for people with diabetes (PWD) include:

• Pump-pocket clothing: brands like AnnaPS and Kinnamon make shorts, tops and underwear with pockets sized for an insulin pump, including a small opening for tubing to pass through, so the pump stays put instead of bouncing around.
  
• No-bounce running belts: SPIbelt and FlipBelt both make belts with a pass-through opening for pump tubing. Many runners with T1D use one of these instead of an armband or a bag, since it keeps supplies close without slowing you down.
  
• CGM adhesive overlays or bands: If you’re worried about a sensor coming loose over 26.2 miles of sweat, an adhesive overlay patch or a band made for your specific sensor adds extra hold on top of what came with it.
  

These are just a few examples, not an exhaustive list, of all the diabetes-friendly marathon products out there. Do some research to find what you think will work best for you. You don’t technically need any of this to run a marathon with T1D, but many runners find it helpful. 

If you’re the type to panic or worry about digging through a bag for your pump or low snacks mid-stride, you may want to consider purchasing something like this that’s designed for your condition. The worst that happens is you don’t like it and have to return it.The best thing that happens is you love it, and it makes your runs a little easier.

After all, this is an investment in your health we’re talking about, and that’s always worth it.

6. Check in with your T1D before the race starts

Check your blood sugar before you start running. Starting around 70 to 180 mg/dL (3.9 to 10.0 mmol/L)  is a reasonable target at the start line, though your care team may set a different range for you specifically. The American Diabetes Association and American College of Sports Medicine recommend delaying exercise if your blood sugar is 250 mg/dl or higher with ketones, or below 100 mg/dl. If you’re low, eat fast-acting carbs and give yourself a few minutes before you start. If you’re high, you can usually still start. Light exercise often brings blood sugar down on its own once you get moving.

Expect nerves to push your blood sugar up even after a correctly dosed breakfast. Adrenaline before a big race does that to almost everyone. Give it time to settle instead of stacking extra insulin on top to correct it. Avoid the rage bolus!

7. Fuel up during the race

Plan to eat carbs during any run longer than 90 minutes. Most runners need somewhere around 30 to 60 grams of carbs per hour to keep blood sugar steady and energy up over that kind of distance—a range sports-nutrition and diabetes exercise research backs up pretty consistently. If you meet other runners with T1D, many of them will tell you how surprised they are at how many carbs they can eat without dosing for them while running a marathon. It’s kind of crazy what your body can go through and how it adjusts!

Always carry more fuel than you think you’ll need: glucose gels, gummies, powders and tablets, chewy candies, fruit snacks, honey packets—all of it works, and the time to figure out what sits well with you is during training, never on race day itself. New low blood sugar treatments like Glow Gummies, ZAP Glucose and LevelUp Diabetes also come in easy-to-carry sizes, and—even better—they’re made by people living with T1D. 

Use medical tents as a backup, not your main plan. Bring your own supplies so you’re not counting on the race to have what you need when you need it. A running belt or gear with real pockets helps, too, since you need to reach fuel and supplies without stopping to dig through a bag.

8. Manage highs and lows

Don’t rely on your CGM alone. CGM readings can lag behind your actual blood sugar by 10 to 20 minutes, especially when levels are changing fast—and during a marathon, they’re changing fast a lot of the time. Carry a backup meter, and confirm with a fingerstick if a CGM reading doesn’t match how you feel.

It helps to raise your low-alert threshold for race day. Many runners set their CGM low alert to around 85 to 90 mg/dL (4.7 to 5.0 mmol/L) during exercise instead of the standard 70 mg/dL (3.9 mmol/L), which buys more time to react before things get urgent. Treat lows right away with fast-acting carbs, then keep moving once you’ve come back up. Needing several small treatments over 26.2 miles is normal. It doesn’t mean you’re doing anything wrong.

Playing with extra adhesives is worth testing during training runs, too—it helps keep a CGM sensor in place through hours of sweat. And keep an eye on insulin on board (IOB), the insulin still active in your body from an earlier dose. It’s easy to forget about, and it can cause a low if you don’t account for it before you eat or bolus again.

9. Stop and get help if you need it: don’t be a hero

Most race-day swings are manageable with the steps above. But a few things mean you stop and find medical staff rather than push through. 

Promptly stop by a medical tent if you experience:

• Confusion or trouble following simple instructions
• A low that isn’t responding after a couple rounds of fast-acting carbs
• Vomiting on top of high blood sugar

None of that is a personal failure. It’s your body telling you something the race can wait for. Medical tents are stationed along the course for exactly this reason. Use them! The race will still be there, and you can get back to it when your body allows. Always prioritize your health first. Everything else will follow as it should.

10. Keep a healthy pace and mindset

There’s no correct pace for a runner with T1D. Walking most of the race and running when you can is a completely valid way to finish—plenty of people do exactly that. Set a steady pace early instead of chasing other runners; it’s a lot easier to keep your blood sugar steady when your effort stays consistent instead of surging and coasting.

Take it slowly if you need to. Listen to your body. That’s more important than running a certain number of miles! Your health should always come first.

The reality is that every marathon runner, regardless of diabetes, faces setbacks while training and race-day doubts. Finishing a race doesn’t require perfection. It means you stayed with your plan and adjusted when necessary. Odds are, you’re already good at doing that, since living with T1D gives you lots of practice in adapting! 

Never forget your strengths or underestimate yourself. And if you do, give yourself grace as you pick yourself up. You got this!

Beyond Type Run’s 2026 team is already assembled, and applications for 2027 won’t open until next spring—keep an eye on Beyond Type Run for updates. In the meantime, cheer on this year’s team at the TCS New York City Marathon alongside the Beyond Type 1 staff! Sometimes the best training and inspiration come from cheering for someone else from the sidelines.