The Diabetes Guide to Running Your First Marathon

So you have diabetes and you want to run a marathon. Good news! It’s absolutely doable and you don’t need to be an experienced runner to cross that finish line. What you do need is a realistic picture of what training and race day actually look like: the good, the messy and the stuff nobody warns you about.

This guide comes from the real experience of a Beyond Type Run team member who ran the TCS New York City Marathon with type 1 diabetes (T1D). If you have type 2 diabetes and use insulin or other glucose-lowering medication, most of this still applies to you, but talk with your healthcare provider (HCP) about how your specific medications interact with long-distance training. Your HCP can help you build a plan that fits your body, not just a generic one.

Here’s what to actually expect, plus what to do about it.

You probably won’t hit your training goal, and that’s fine

Most first-time marathoners don’t run their full training mileage before race day. Between work, life and a body that’s also managing blood glucose, it’s common to top out well under the “ideal” long run distance you see in training plans. That’s not a sign you’re not ready. Show up on race day with whatever training you’ve got. Plenty of people finish having power-walked a large part of the course.

What to do: Alternate running and walking during training instead of forcing continuous running. It’s easier on your body and your blood glucose, and it’s exactly what a lot of finishers actually do on race day.

Skip the comparison game

If you’re training with a team or following other runners on social media or Strava, you’re going to see people posting 15, 18 and 20-mile weeks. That can feel discouraging on days your blood glucose or your body won’t let you push past a few miles. Everyone’s training looks different, and everyone’s diabetes management looks different too. Your job is to train for your race, not theirs.

What to do: Focus on progress, not perfection.

Handle logistics one step at a time

Bib pickup, race-day gear, getting to the start on time—the logistics leading up to marathon day can feel more stressful than the race itself. Don’t try to plan every detail weeks in advance. Handle each step as it comes: pickup day, then gear the night before, then race morning. Trying to solve it all at once is where the overwhelm comes from.

What to do: A few days before race day, pack a “race bag” with everything you’ll need: backup CGM sensor, fast-acting glucose, snacks, extra layers and any medical ID, so morning-of decisions are minimal.

Prepare for a long, cold wait at the start

The start village is often the hardest part of the whole day, not the running. You may be waiting outside for hours before your wave starts, and it gets cold. Bring more warm layers than you think you need, including ones you’re fine with donating right before the race starts. Bring your own food too since options at the start are limited.

Protect your glucose meter from the cold

Cold weather can cause glucose meters to stop reading accurately or at all. If you’re relying on a meter as well as a CGM, keep the meter in an inner pocket close to your body rather than in an outer bag, and consider a small insulated pouch or a hand warmer packet next to it.

What to do: Know where the medical tents are along the route too—they’re stocked and staffed, and stopping at one to get a reading or ask a question is completely normal.

Expect nerves to spike your blood glucose

Pre-race adrenaline can send your blood sugar up even after you’ve dosed appropriately for breakfast. This is common and it doesn’t necessarily mean you need to correct right away. Give it time to settle once you start moving. Many runners see their levels come down naturally in the first couple of miles.

What to do: Talk with your HCP ahead of time about how to handle pre-race spikes and what your correction plan should look like based on your insulin regimen.

Pack more fast-acting carbs than you think you’ll need

Energy gels, chews and electrolyte packets are what get most runners with diabetes through a marathon. Expect at least a few real blood sugar crashes over 26.2 miles, even with good planning. Some runners also find pretzels or other real food easier to manage than another gel.

What to do: Carry more fuel than feels necessary and treat the medical tents as a backup, not a first resort.

Trust your own pace

There’s no “right” pace for finishing a marathon with diabetes. A fast walk and a slow run get you to the same finish line. Find your pace early and hold it steady, and give yourself full permission to stop when your body tells you to. Stopping isn’t quitting. Knowing when to pause and when to push a little further is a skill, and it’s one you already have practice with from managing diabetes day to day.

What to do: Listen to your body!

Get your HCP involved

Before race day, build a simple plan with your HCP that covers three things:

• How you’ll adjust insulin or medication for the day of your first marathon
• What your fast-acting carb plan looks like on the course
• What your backup plan is if your meter or CGM has issues.

Having that plan settled ahead of time means fewer decisions to make when you’re tired and 15 miles in.

Remember: you can do this

Every runner who’s ever crossed a marathon finish line with diabetes has had a rough training block, a scary low or a moment at mile 20 where they doubted themselves. That’s part of the process, not a sign you’re not cut out for it. Show up, listen to your body and trust that you know how to handle whatever the day brings. You’ve been managing diabetes for a while now. This is just a longer, sweatier version of that same skill.

Ready to take this on with a team who gets it? Beyond Type Run connects you with other runners managing diabetes, training support and a community that’s already been through race day. Learn more about Beyond Type Run.