The fastest way to increase blood glucose is to consume 15 grams of fast-acting carbohydrates, such as glucose tablets, juice, or regular soda. This can raise your blood sugar above 70 mg/dL within about 15 minutes. But the right approach depends on why your glucose is low: whether you’re treating an immediate low, managing drops during exercise, or trying to prevent recurring crashes throughout the day.
Recognizing Low Blood Sugar
Blood sugar below 70 mg/dL is considered low (hypoglycemia). At this level, you’ll typically notice early warning signs: shakiness, sweating, a rapid heartbeat, sudden hunger, or feeling anxious and irritable. These symptoms come from your body releasing stress hormones to signal that it needs fuel.
If glucose drops below 54 mg/dL, the symptoms shift from uncomfortable to dangerous. Your brain isn’t getting enough sugar to function properly, which can cause confusion, blurred vision, slurred speech, difficulty concentrating, and poor coordination. At the most severe stage, you may need someone else’s help because you’re too confused or physically impaired to treat yourself. Seizures, loss of consciousness, and coma are possible.
The 15-15 Rule for Quick Treatment
The standard approach recommended by the CDC is called the 15-15 rule: eat or drink 15 grams of fast-acting carbohydrates, wait 15 minutes, then recheck your blood sugar. If it’s still under 70 mg/dL, repeat. Each of the following provides roughly 15 grams of quick-acting sugar:
- Glucose tablets: 3 to 4 tablets
- Fruit juice or regular soda: 4 to 6 ounces (about half a cup)
- Table sugar: 1 tablespoon
- Honey: 1 tablespoon
- Hard candy: 6 Life Savers
Glucose tablets are the most precise option because they’re pre-measured, and they dissolve quickly. Juice and regular soda work well too, but avoid diet versions since they contain no sugar. Chocolate and other fatty foods are poor choices here because fat slows digestion, delaying the glucose spike you need.
Once your blood sugar is back above 70 mg/dL, eat a small meal or snack that includes protein and complex carbohydrates. Something like cheese and whole-grain crackers, a handful of nuts with fruit, or peanut butter on toast. This follow-up prevents your glucose from crashing again once the fast-acting sugar is used up.
When Someone Can’t Treat Themselves
Severe hypoglycemia, where a person is confused, unconscious, or having a seizure, requires glucagon. This is a hormone that signals the liver to release its stored sugar into the bloodstream. It’s available as a nasal spray that requires no preparation (you simply spray it into one nostril) and as a pre-filled injector similar to an EpiPen that goes into the thigh. Both are designed so that a family member, coworker, or bystander can administer them without medical training.
If you take insulin or medications that can cause low blood sugar, keeping a glucagon kit accessible and making sure the people around you know where it is and how to use it can be lifesaving. Nearly 50% of all severe hypoglycemic episodes happen at night during sleep, when the person experiencing them may not wake up in time to treat themselves.
Raising Glucose During Exercise
Physical activity pulls sugar out of your bloodstream and into your muscles for fuel, which is why blood sugar can drop during workouts. If you exercise for about an hour, even a small amount of carbohydrate, or simply rinsing your mouth with a carbohydrate drink, has been shown to help maintain performance and prevent a dip.
For longer sessions, the American College of Sports Medicine recommends 30 to 60 grams of carbohydrates per hour. Your body can absorb and use a single carbohydrate source (like a sports drink or banana) at rates up to about 60 grams per hour. For ultra-endurance events lasting several hours, the recommendation increases to around 90 grams per hour, which typically requires combining multiple carbohydrate types (glucose plus fructose, for example) to avoid overwhelming your gut’s absorption capacity. Research shows the greatest performance benefit comes from consuming 60 to 80 grams per hour during prolonged activity.
Practical options include sports drinks, energy gels, bananas, dried fruit, or pretzels. If you’re prone to exercise-related blood sugar drops, eating a balanced meal with carbohydrates and protein one to two hours before your workout gives you a more stable starting point.
Preventing Recurring Blood Sugar Drops
If your blood sugar drops regularly, especially after meals, you may be dealing with reactive hypoglycemia. This happens when your body overproduces insulin in response to a meal, causing glucose to plummet roughly 2 to 4 hours after eating. The fix isn’t to keep reaching for candy. Instead, it’s about changing what and how you eat so the spikes and crashes don’t happen in the first place.
Simple carbohydrates like white bread, white rice, pastries, candy, and sweetened drinks break down into glucose almost immediately. That rapid flood of sugar triggers a large insulin response, which then drives your blood sugar down too far, too fast. Swapping these for low-glycemic complex carbohydrates creates a gentler, more gradual rise and fall. Good options include brown or wild rice, quinoa, oatmeal, barley, and bean-based pastas. Black beans and chickpeas are especially useful because they’re high in both fiber and protein, two nutrients that slow digestion and keep glucose steadier.
Pairing any carbohydrate with a protein source makes a meaningful difference. Adding meat, nuts, eggs, or dairy to a meal or snack slows the rate at which sugar enters your bloodstream and helps you stay fuller longer. Eating smaller, more frequent meals rather than two or three large ones also helps by reducing the size of each blood sugar swing.
Preventing Overnight Drops
Nocturnal hypoglycemia is particularly common in people with type 1 diabetes on insulin therapy. It’s often silent: blood sugar drops during sleep without producing symptoms strong enough to wake you up. Almost half of all severe hypoglycemic episodes occur overnight, and repeated exposure can dull your body’s warning signals over time, making future lows even harder to detect.
Checking blood sugar at bedtime is the most important preventive step. If it’s trending low, a bedtime snack combining slow-digesting carbohydrates with protein and fat can help sustain glucose levels through the night. Think a small bowl of oatmeal with nuts, apple slices with peanut butter, or whole-grain crackers with cheese. A continuous glucose monitor with low-glucose alerts provides an additional layer of safety by waking you (or a caregiver) when levels start dropping.