Yes, you can play sports with diabetes. Both type 1 and type 2 diabetes are fully compatible with athletic competition at every level, from recreational leagues to the Olympics. NFL quarterback Jay Cutler, Olympic swimming gold medalist Gary Hall Jr., and tennis world #2 Alexander Zverev all compete with type 1 diabetes. The key isn’t whether you can play, but how you manage your blood sugar before, during, and after activity.
How Exercise Affects Blood Sugar
When your muscles contract during exercise, they pull glucose out of your bloodstream for fuel. This happens through a pathway that works independently of insulin: muscle contractions cause glucose transporters to move to the surface of muscle cells, creating more entry points for sugar to flow in. This is one reason exercise is so beneficial for people with diabetes. It’s essentially a second way to lower blood sugar that doesn’t rely on your body’s insulin supply.
A single bout of exercise increases glucose uptake both during the activity and for several hours afterward. For people with type 2 diabetes, this means regular physical activity directly improves insulin sensitivity over time. For people with type 1, it means exercise is a powerful tool, but one that requires careful planning to avoid blood sugar dropping too low.
Why Intense Exercise Can Raise Blood Sugar
Here’s something that surprises many people: high-intensity activities like sprinting, heavy weightlifting, or interval training can temporarily raise your blood sugar instead of lowering it. During intense bursts, your body releases stress hormones like adrenaline and glucagon, which signal your liver to dump stored glucose into the bloodstream. In people with type 2 diabetes, these hormonal responses tend to be exaggerated compared to people without diabetes, sometimes producing elevated blood sugar that lasts up to 60 minutes after the workout.
For people with type 1 diabetes, blood sugar is generally higher during and up to two hours after high-intensity exercise compared to moderate, steady activity. This doesn’t mean you should avoid intense sports. It means the type of activity you choose will affect your blood sugar in different, sometimes opposite, directions. Knowing this lets you plan ahead.
Pre-Exercise Blood Sugar Targets
If you have type 1 diabetes, checking your blood sugar before exercise is essential. The American Diabetes Association recommends starting exercise when your blood sugar is between 90 and 250 mg/dL. What you do depends on where you fall in that range:
- Below 90 mg/dL: Eat 15 to 30 grams of fast-acting carbohydrates before starting. Short, intense activities under 30 minutes (like weight training or sprints) may not need extra carbs.
- 90 to 150 mg/dL: Start eating carbohydrates at the beginning of most exercise, roughly 0.5 to 1.0 grams per kilogram of your body weight per hour, depending on intensity and how much insulin is active in your system.
- 150 to 250 mg/dL: Go ahead and start exercising. Hold off on carbohydrates until your blood sugar drops below 150 mg/dL.
- Above 250 mg/dL: Check for ketones. If ketones are present, skip the workout until levels come down. Exercising with high ketones can make things worse.
For people with type 2 diabetes who manage with diet, oral medications, or non-insulin injectables, the risk of exercise-induced low blood sugar is much lower. You generally don’t need to follow these thresholds as strictly, though checking before and after activity helps you learn your patterns.
Fueling During Longer Activities
For sustained activities lasting more than 30 minutes, like a soccer match, a long bike ride, or a basketball game, you’ll need carbohydrates to keep your blood sugar stable. The general sports nutrition guideline is 30 to 60 grams of carbohydrates per hour for activities lasting one to three hours. For ultra-endurance events, that recommendation climbs to around 90 grams per hour.
For children and adolescents with type 1 diabetes, the ADA suggests 5 to 15 grams of carbohydrates for every 30 minutes of sustained activity, adjusted for the child’s size and starting blood sugar. Frequent blood sugar checks during long activities are the only reliable way to know if your fueling strategy is working. Everyone responds differently, and it takes some trial and error to find your rhythm with a specific sport.
Type 1 vs. Type 2: Different Challenges
The biggest difference between managing type 1 and type 2 diabetes during sports comes down to insulin. If you have type 1 diabetes, you’re balancing injected or pumped insulin against the blood-sugar-lowering effect of exercise. Too much active insulin plus vigorous activity can cause a dangerous drop. That’s why many athletes reduce their insulin dose before exercise: a 25% to 75% reduction in bolus insulin for workouts done within two to three hours of a dose is a common strategy. Pump users sometimes reduce or suspend their basal rate 30 to 60 minutes before starting.
If you have type 2 diabetes, exercise generally works in your favor. Physical activity improves how well your cells respond to insulin, and the glucose-lowering effects persist for hours after you stop. The main concern is if you take medications that can cause low blood sugar, like sulfonylureas or insulin. In those cases, you’ll want to monitor more carefully and possibly adjust timing or doses with your doctor’s guidance.
Managing Devices During Contact Sports
Insulin pumps and continuous glucose monitors (CGMs) add a practical layer to playing sports. For non-contact activities like swimming, cycling, or tennis, most people keep their devices on without issue. Contact sports require more thought.
Many athletes remove their insulin pump during football, rugby, basketball, or martial arts to avoid a defender grabbing the tubing or an impact ripping out the site. If you disconnect your pump, you’ll need backup insulin in the form of injections and extra pump sites on hand. For CGMs or infusion sites that stay on, placing the site on the upper thigh or another protected area, then covering it with a quarter-inch of foam padding secured with athletic tape, works well. Even with protection, expect the occasional site to get knocked loose during contact sports. Having replacements ready is part of the routine.
Complications That Affect Exercise Choices
Most people with diabetes can do any sport they want. But two complications, when they’re advanced, call for some modifications.
If you have proliferative retinopathy (a condition affecting blood vessels in the eye), avoid activities that involve heavy straining, breath-holding while lifting, high-impact jarring, or head-down positions. These can increase pressure in the eye and raise the risk of bleeding. Sports like powerlifting, boxing, or certain gymnastics movements fall into this category. Moderate aerobic exercise like walking, cycling, or swimming is typically fine.
If you have peripheral neuropathy, meaning reduced sensation in your feet, the concern shifts to injury you might not feel. Prolonged weight-bearing activities like long-distance running, high-impact jumping, and exercising in extreme heat or cold carry higher risk. Non-weight-bearing options like swimming, cycling, or upper-body training let you stay active without stressing vulnerable feet. Never exercise with an open sore or ulcer on your foot.
Building Your Sports Routine
The practical side of playing sports with diabetes comes down to preparation. Carry fast-acting carbohydrates (glucose tablets, juice, or candy) every time you train or compete. Check your blood sugar before, during breaks, and after activity until you understand how that specific sport affects you. Keep a log of what you ate, your insulin doses, your blood sugar readings, and how you felt. Patterns emerge quickly, and within a few weeks you’ll have a personalized playbook for your sport.
If you use a CGM, the real-time data takes much of the guesswork out. You can see trends mid-game and catch a dropping blood sugar before it becomes a problem. For team sports, let your coach and at least one teammate know you have diabetes and where your supplies are. This isn’t about limiting yourself. It’s about removing the one barrier between you and playing the sport you want to play.