Hyperglycemia, or high blood sugar, is treated through a combination of medication, insulin therapy, dietary changes, exercise, and regular monitoring. The specific approach depends on whether you have type 1 or type 2 diabetes, how high your blood sugar is, and whether the spike is a short-term episode or a chronic pattern. For most nonpregnant adults with diabetes, the goal is to keep blood sugar between 80 and 130 mg/dL before meals and below 180 mg/dL one to two hours after eating.
Medications for Type 2 Diabetes
If you have type 2 diabetes, oral or injectable medications are typically the first line of treatment. The most commonly prescribed is metformin, which works in two ways: it reduces the amount of glucose your liver produces and makes your muscle tissue more sensitive to insulin so your cells can absorb blood sugar for energy. Most people with a new type 2 diagnosis start here.
When metformin alone isn’t enough, your doctor may add other medication classes. SGLT2 inhibitors work through the kidneys, blocking them from reabsorbing glucose back into your blood. The excess sugar gets eliminated in your urine instead, which can also lead to modest weight loss and small drops in blood pressure. GLP-1 receptor agonists are injectable medications that mimic a natural gut hormone to stimulate insulin release and slow digestion. These tend to produce significant reductions in both blood sugar and body weight. A newer class combines GLP-1 with a second gut hormone (GIP) for even stronger effects.
Insulin Therapy
People with type 1 diabetes need insulin to survive, since their bodies produce little or none of it. Many people with type 2 diabetes eventually need insulin as well, especially if oral medications stop providing adequate control. Insulin comes in several types, each with a different speed and duration of action:
- Rapid-acting insulin starts working within 15 minutes, peaks at about 1 hour, and lasts 2 to 4 hours. It’s taken right before or with meals to handle the glucose spike from food.
- Regular (short-acting) insulin kicks in within 30 minutes, peaks at 2 to 3 hours, and lasts 3 to 6 hours.
- Intermediate-acting insulin takes 2 to 4 hours to begin working, peaks between 4 and 12 hours, and lasts 12 to 18 hours.
- Long-acting insulin starts working after about 2 hours, has no sharp peak, and provides steady background coverage for up to 24 hours.
Most insulin regimens combine a long-acting insulin for baseline coverage with a rapid-acting insulin at mealtimes. The exact combination and doses are adjusted over time based on your blood sugar patterns. Different brands of the same type can vary in how they behave, so it’s important to stick with consistent products unless your doctor makes a change.
Dietary Changes That Lower Blood Sugar
What you eat has an immediate, measurable effect on blood sugar. Two concepts help explain why: the glycemic index (GI) scores foods from 0 to 100 based on how fast they raise blood sugar, with pure glucose at 100. But GI alone can be misleading. Watermelon has a high GI of 80, yet a typical serving contains so little carbohydrate that its real-world impact (called glycemic load) is only 5. Glycemic load accounts for both speed and quantity of carbohydrate, giving a more accurate picture of how a food actually affects your blood sugar.
In practical terms, this means choosing foods with both low GI and moderate carbohydrate content: non-starchy vegetables, most legumes, whole grains like steel-cut oats, nuts, and many fruits. Pairing carbohydrates with protein, fat, or fiber slows digestion and blunts the post-meal glucose spike. Portion control matters as much as food choice, since even low-GI foods raise blood sugar significantly in large amounts.
How Exercise Lowers Blood Sugar
Physical activity pulls glucose out of your bloodstream even without extra insulin. During exercise, increased blood flow and changes in your muscle cells trigger glucose transporters to move to the cell surface, where they shuttle sugar directly into the muscle for energy. This process works independently of insulin, which is why a walk after a meal can bring down a blood sugar spike relatively quickly.
Both aerobic exercise (walking, cycling, swimming) and resistance training improve blood sugar control. A single session can lower glucose levels for hours afterward, and regular activity improves your body’s overall sensitivity to insulin over time. If your blood sugar is extremely high (above 240 mg/dL) and you have ketones in your urine, exercise can actually make things worse, so checking before vigorous activity is worthwhile.
Monitoring Your Blood Sugar
Treatment only works if you know what your blood sugar is doing throughout the day. Fingerstick glucose meters give you a snapshot at a single moment. Continuous glucose monitors (CGMs) track your levels every few minutes through a small sensor worn under the skin, giving you a real-time graph and alerting you to highs and lows.
If you use a CGM, the key metric is “time in range,” the percentage of the day your blood sugar stays between 70 and 180 mg/dL. Most people should aim for at least 70% of readings in range, which works out to roughly 17 out of 24 hours. This number gives a much more complete picture than a single fasting reading or even an A1C test, because it captures the spikes and dips that happen between meals, during sleep, and after exercise.
Managing Blood Sugar When You’re Sick
Illness, infections, and even stress hormones can push blood sugar significantly higher than usual, even if you haven’t changed your diet or medication. During illness, the CDC recommends checking your blood sugar every 4 hours and keeping a written log so you can spot trends. Drink plenty of water to prevent dehydration, which worsens hyperglycemia. If you can’t eat regular meals, aim for about 50 grams of carbohydrates every 4 hours to keep some fuel coming in without causing wild swings.
Ketone monitoring becomes especially important when you’re sick. High blood sugar combined with illness can trigger diabetic ketoacidosis (DKA), a dangerous condition where your body starts breaking down fat too quickly and produces acidic byproducts called ketones. Over-the-counter urine test strips can detect ketones at home. If ketones show up, that’s a sign to seek medical care immediately.
Avoiding Low Blood Sugar During Treatment
One of the risks of treating hyperglycemia, particularly with insulin, is overcorrecting into hypoglycemia. For people with diabetes, low blood sugar is generally defined as a reading below 70 mg/dL. Mild episodes cause shakiness, sweating, confusion, and irritability, and can be reversed by eating 15 to 20 grams of fast-acting carbohydrates (glucose tablets, juice, or regular soda). Severe hypoglycemia can cause loss of consciousness and requires emergency treatment.
The most common triggers are taking too much insulin, mistiming insulin relative to meals (such as injecting and then waiting too long to eat), taking too high a dose of oral diabetes medication, and being more physically active than usual without adjusting food or medication. Injecting insulin into muscle instead of fat tissue can also cause it to absorb too quickly. Recognizing these patterns helps you anticipate and prevent dangerous lows while still keeping your blood sugar in a healthy range.