Running with type 1 diabetes: a solo safety plan

Why a run changes your glucose

The American Diabetes Association explains that exercise improves insulin sensitivity, and that when your muscles contract, your cells can take up glucose and use it for energy whether insulin is available or not. That is a big part of why running is good for you, and it is also why a run can pull your glucose down.

The ADA says people taking insulin or insulin secretagogues are at risk of low blood glucose during exercise, especially if they skip meals or exercise for a long time or at high intensity, and that lows can occur during or long after activity. The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) adds that physical activity can lower blood glucose for hours afterward, and that symptoms of a low tend to come on quickly and vary from person to person. On a solo run, that speed is the thing to plan around. A low that a friend would spot in a minute can go unnoticed when you are alone.

This page is general information, not medical advice. Work out your own plan with your diabetes care team, including your targets, insulin adjustments and what to eat before and during a run.

Before the run: questions for your care team

The ADA recommends talking with your diabetes care team about your risk of lows with exercise, and notes they may suggest a snack before exercise or a medication adjustment, particularly for longer workouts. Some useful questions:

• What glucose range should I be in before starting a run, and what should I do if I am below it?
• Should I change my insulin or eat a snack before runs, and does that change for a long run versus an easy one?
• How often should I check, or glance at my CGM, during longer runs?
• How should I watch for lows later in the day or overnight after a hard session?
• Should I carry glucagon, and who around me should learn how to give it?

On the run: carry the fix, and stay close to help

The ADA's exercise guidance gives specific numbers: if your reading is 100 mg/dL or lower during exercise, have 15 to 20 grams of carbohydrate (such as 4 glucose tablets or 4 ounces of juice), wait 15 minutes and recheck, repeat if you are still below 100, and start exercising again only once you are back above 100 mg/dL. Your care team may give you different numbers, so follow theirs.

For a solo runner, that means the fix has to come with you every time, along with a way to know your number.

• Carry more fast-acting carbs than you think you need, in a pocket you can reach without stopping to dig.
• Carry your meter, or keep your CGM receiver or phone on you and charged. The NIDDK notes a CGM can sound an alarm if your glucose drops below your target range.
• Choose loops that pass your home, car or a store, so a low does not strand you far from supplies.
• Wear a medical ID. The NIDDK recommends a medical alert bracelet or pendant because it tells other people you have diabetes and need care right away. See what to put on a medical ID and make a printable emergency card with your condition, insulin and contacts.
• In heat, dizziness and confusion can come from heat illness as well as a low. Our guide on heat safety for runners covers the warning signs.

Where Holler fits alongside your CGM

Many continuous glucose monitors can alert you to a low, and some can share readings with a follower. If yours can, it is worth setting up. Holler does something different: it shares where you are and notices when a run does not go to plan. It cannot sense glucose, and it does not know you are low.

What Holler can do is catch the situation a severe low tends to create. Set a return time on every solo run. If you have not checked in five minutes after it, your Guardians get an overdue alert from Holler's server, even if your phone app is closed. A stationary alert asks "Are you OK?" when you stop moving for the time you choose and alerts your Guardians if you do not answer. Set it longer than the 15-minute recheck window, so treating a mild low at the side of the path does not trigger it, and it only fires when you cannot respond.

Your Guardians follow your live location link in any browser. In a phone browser, sharing and the stationary alert only work while the page is open and the screen is on. If you feel a low coming and are worried, tap SOS so your Guardians have your location while you treat it. Holler does not contact 911.

A long run, set up start to finish

Here is one way a runner might set up a Saturday 90-minute run, using numbers their care team already agreed. They check before leaving and follow their team's pre-run plan. Pockets: glucose tablets, a gel, phone with the CGM app. Bracelet on.

They start an outing with a return time of 1 hour 50 minutes and a stationary alert set to 20 minutes. At minute 50 their CGM alarms. They stop on a bench, take glucose tablets, and wait. Fifteen minutes later they recheck; still under 100, they take more. A few minutes later the stationary alert reaches 20 minutes and asks "Are you OK?"; they answer it, so their Guardian is not alerted. Back above 100, they walk the last stretch home and end the outing, which is the check-in.

Had they not answered, their Guardian would have seen the alert and the location on the map. The message they sent that Guardian once, when setting it up: "If you get an alert from my run, call me. If I don't answer within two minutes, call 911, say I have type 1 diabetes and may have low blood sugar, and give them the location from the link. Glucose tablets are in my left pocket."

What your Guardian should know

The NIDDK recommends teaching family, friends and coworkers when and how to give you glucagon, and telling them to call 911 right away after giving it or if you do not have a glucagon kit with you. For a Guardian watching from a distance, that becomes a few specific things.

• An alert from a runner with type 1 diabetes deserves a faster response than usual. Call first. If you do not answer within a couple of minutes, they should not wait for more certainty.
• The ADA is direct: do not hesitate to call 911, and if someone is unconscious and glucagon is not available, call 911 immediately. Your Guardian should tell the dispatcher you have type 1 diabetes and may have low blood glucose, and give the location from the link.
• If they reach you in person or talk a bystander through it, they should know where you keep fast carbs and glucagon. If you cannot eat or drink safely, calling 911 comes first.
• If you share CGM data with them, agree on which readings should prompt a call even when no Holler alert has fired. Our guide on what to do if your runner stops moving covers the general steps.