When your blood sugar is high, the most effective immediate steps are drinking water, moving your body if it’s safe to do so, and checking whether you need a correction dose of insulin if that’s part of your treatment plan. A fasting blood sugar of 126 mg/dL or higher falls into the diabetes range, and a random reading of 200 mg/dL or higher signals a problem worth acting on. What you do next depends on how high the number is and what symptoms you’re experiencing.
Drink Water First
Water helps your kidneys filter excess sugar out of your blood through urine. The more hydrated you are, the more urine your body produces, which flushes glucose from your system. This won’t bring a dangerously high reading back to normal on its own, but it’s a simple first step that supports everything else you do. Stick with plain water. Soda, juice, and sweetened drinks will push your levels higher.
Move Your Body (When It’s Safe)
Physical activity pulls sugar from your bloodstream into your muscles for energy. A 15 to 30 minute walk after a high reading can make a noticeable difference. Even light movement like household chores helps.
There’s one important exception. If your blood sugar is over 250 mg/dL, check for ketones before exercising. Ketones are acids your body produces when it starts burning fat instead of glucose for fuel, a sign that insulin levels are too low. You can test for them with urine strips available at most pharmacies. If ketones are present, skip the exercise. Vigorous activity when ketones are in your system can actually make blood sugar climb higher and push you toward a dangerous condition called diabetic ketoacidosis.
Adjust Insulin Carefully
If you take insulin, a correction dose may be appropriate. But timing matters. Wait at least three hours between correction doses to avoid what’s called “insulin stacking,” where multiple doses overlap and cause your blood sugar to crash too low. If you took insulin less than three hours ago, it’s still working in your system, and adding more can lead to hypoglycemia.
If you’re unsure how much to correct, follow the specific guidance your provider gave you. Correction ratios vary from person to person, and guessing can be risky in either direction.
Choose Foods That Won’t Make It Worse
When your blood sugar is already high, the last thing you want is a snack that sends it higher. But skipping meals entirely can backfire too, especially if you’re on medication that lowers blood sugar on a schedule. The goal is to eat foods that digest slowly and don’t cause a secondary spike.
Good options include:
- Nuts: A small handful (about 1.5 ounces) of almonds, walnuts, or pistachios is high in fiber with very few carbs.
- Eggs: Scrambled egg whites or hard-boiled eggs are pure protein with no carb impact.
- Cheese: A piece of low-fat string cheese or a quarter cup of cottage cheese paired with a small amount of fruit.
- Hummus with vegetables: About a third of a cup gives you fiber and protein. The carbs from chickpeas absorb slowly and won’t spike your levels the way bread or crackers would.
- Plain yogurt: Low-fat, unsweetened yogurt with fresh berries. Avoid flavored varieties, which are often loaded with added sugar.
- Air-popped popcorn: Three cups is a reasonable portion that won’t overload on carbs.
The common thread is protein, healthy fat, and fiber. These slow digestion and keep glucose from flooding your bloodstream all at once.
Check for Ketones at 250 mg/dL
If your blood sugar reads over 250 mg/dL on two consecutive tests, test for ketones. This applies whether you have type 1 or type 2 diabetes, though ketone emergencies are more common in type 1. Urine ketone strips change color to indicate the level. A small or trace amount may be manageable at home with fluids and insulin. Moderate to large ketone levels need medical attention.
If you’re pregnant, the threshold is even more important. Test for ketones every morning before breakfast and any time your reading exceeds 250 mg/dL.
Recognize When It’s an Emergency
Most high blood sugar episodes come down gradually with water, movement, and medication. But some situations require emergency care. Head to the ER or call emergency services if your blood sugar is above 300 mg/dL on more than one test, you have ketones in your urine and can’t reach your healthcare provider, or you’re experiencing multiple symptoms of diabetic ketoacidosis.
Those symptoms include:
- Extreme thirst that doesn’t go away with drinking
- Frequent urination
- Nausea or vomiting
- Abdominal pain
- Weakness or exhaustion
- Shortness of breath
- Breath that smells fruity or sweet
- Confusion or difficulty concentrating
Diabetic ketoacidosis can develop within hours and is life-threatening without treatment. Don’t wait to see if symptoms improve on their own once several of these are present together.
Preventing the Next Spike
If you’re dealing with frequent high readings, the pattern matters more than any single number. Track when your spikes happen. Are they after meals, in the morning, or overnight? This information helps identify whether the issue is food timing, medication dosing, stress, illness, or something else entirely.
Common triggers include eating more carbohydrates than your body can process at once, missing or delaying medication, illness or infection (which raises blood sugar even without dietary changes), stress hormones, and dehydration. Some people notice consistent morning highs caused by the “dawn phenomenon,” where the body releases hormones in the early hours that push glucose up before you even eat.
If high readings keep recurring despite following your treatment plan, your medication dose or timing may need adjustment. Frequent hyperglycemia is a signal that your current regimen isn’t matching your body’s needs, and that’s worth a conversation with your provider sooner rather than later.