When your blood sugar is running high, drinking water, moving your body, and choosing the right foods can all help bring it down within hours. A normal fasting blood sugar is under 100 mg/dL, while readings of 126 mg/dL or higher on a fasting test indicate diabetes. If your meter is showing elevated numbers and you’re looking for what to do right now, several strategies can help, though the right approach depends on how high your levels are and whether you use insulin.
Drink Water to Dilute Excess Glucose
Dehydration concentrates the sugar in your bloodstream, which means less water in your body directly translates to higher readings on your meter. Drinking water helps your kidneys flush out excess glucose through urine, and it counteracts the dehydrating effect of high blood sugar itself (when glucose is elevated, your body pulls water from tissues to try to dilute it, which is why you urinate more and feel thirsty).
There’s no single magic number for how much to drink during a spike, but steady sipping is more effective than gulping a large amount at once. Aim to drink a glass of water every 30 to 60 minutes until your levels start coming down. Stick with plain water or unsweetened beverages. Even “healthy” drinks like fruit juice or sweetened tea will push your glucose higher.
Use Movement Carefully
Physical activity is one of the fastest ways to lower blood sugar because your muscles pull glucose out of your bloodstream for energy. A 15- to 30-minute walk after a meal can noticeably reduce a postmeal spike. Even light movement like cleaning the house or doing yard work helps.
However, exercise is not always safe during a blood sugar spike. The American Diabetes Association recommends that people with type 1 diabetes test for ketones when blood sugar is at or above 250 mg/dL. If ketones are moderate to high (1.5 mmol/L or above on a blood ketone meter), exercise should be postponed entirely, because physical activity can actually push both glucose and ketones higher in that situation. At readings of 350 mg/dL or above, ketone testing is essential before any activity. If you have type 2 diabetes and don’t typically produce ketones, a short walk is generally safe even at higher readings, but if you feel nauseated, dizzy, or short of breath, stop and sit down.
Choose Foods That Slow Glucose Absorption
If you’re hungry while your blood sugar is elevated, what you eat next matters a lot. Fiber, protein, and healthy fats all slow down digestion and prevent further spikes. Soluble fiber, the kind found in oats, beans, lentils, and avocados, dissolves in your stomach and forms a gel-like substance that slows glucose absorption. Your body doesn’t break fiber down into sugar the way it does other carbohydrates, so high-fiber foods have a much smaller impact on your meter.
Some practical combinations that work well: a handful of almonds or walnuts, celery with peanut butter, a hard-boiled egg, or plain Greek yogurt. If you’re going to eat carbohydrates, pairing them with protein or fat makes a meaningful difference. Toast with avocado and chickpeas, for example, will raise your blood sugar far less than toast alone. Avoid refined carbohydrates like white bread, crackers, cereal, and anything sweetened until your levels have come back into a comfortable range.
Manage Stress to Stop Fueling the Spike
Stress raises blood sugar even if you haven’t eaten anything. When you’re anxious or under pressure, your body releases cortisol and adrenaline, which trigger your liver to dump stored glucose into your bloodstream. These same hormones also make your cells more resistant to insulin, so the glucose lingers longer than it normally would. It’s a double hit: more sugar entering the blood and less ability to clear it.
This means that stressing about a high reading can, ironically, keep it elevated. Slow, deep breathing for five to ten minutes has a measurable calming effect on the hormonal cascade that drives stress-related spikes. Breathing in for four counts, holding for four, and exhaling for six is a simple pattern that activates your body’s relaxation response. Other options include a short meditation, progressive muscle relaxation, or simply stepping outside for fresh air. If you notice your blood sugar tends to climb during stressful periods at work or during poor sleep, the pattern is likely cortisol-driven.
If You Take Insulin: Avoid Stacking Doses
If you use rapid-acting insulin and your blood sugar is high, a correction dose can bring it down. But one of the most common mistakes is taking another correction too soon when the first dose doesn’t seem to be working fast enough. Rapid-acting insulin starts working about 15 minutes after injection, peaks around one hour, and stays active for two to four hours. Taking a second correction before the first dose has finished working is called “insulin stacking,” and it’s a leading cause of dangerous low blood sugar.
The general safety rule is to wait at least three hours between correction doses. If you’re eating during that window, you can still take insulin to cover the carbohydrates in your meal, but you should use only your carb-to-insulin ratio for that calculation rather than adding another correction on top. If your blood sugar hasn’t come down after three hours and a full correction dose, that’s a sign something else may be going on: a bad infusion site if you use a pump, expired insulin, illness, or a need to adjust your correction factor with your care team.
Know What Counts as an Emergency
Most high blood sugar episodes can be managed at home, but some situations require immediate medical attention. Diabetic ketoacidosis, or DKA, happens when your body starts breaking down fat for fuel because it can’t access glucose, producing dangerous levels of acids called ketones. It’s most common in type 1 diabetes but can occur in type 2 as well.
Go to the emergency room if you experience any of the following alongside high blood sugar:
- Nausea or vomiting that won’t stop
- Abdominal pain
- Rapid, deep breathing that feels labored or involuntary
- Fruity-smelling breath
- Confusion or disorientation
- Extreme fatigue or weakness beyond what feels normal
Fruity breath and rapid deep breathing are two of the most distinctive warning signs of DKA. If someone with diabetes becomes confused or loses consciousness, call emergency services immediately. DKA can progress from uncomfortable to life-threatening within hours.
Building a Routine That Prevents Spikes
Treating a high reading in the moment is important, but the bigger win is reducing how often spikes happen in the first place. A few patterns make the most difference over time. Eating protein or fat before or alongside carbohydrates at every meal slows glucose absorption consistently. Spreading fiber throughout the day, starting with breakfast (oatmeal with nuts and berries, or eggs with vegetables), keeps your baseline more stable.
Walking for even 10 to 15 minutes after meals is one of the most effective habits for postmeal control, and it requires no equipment or gym membership. Staying hydrated throughout the day, rather than only when you notice a spike, helps your kidneys manage glucose continuously. And prioritizing sleep matters more than most people realize: even one night of poor sleep increases insulin resistance the following day, which means the same foods will push your blood sugar higher than they normally would.
Tracking your readings before and two hours after meals for a week or two can reveal which specific foods and situations cause your biggest spikes. That data is far more useful than general dietary rules, because individual responses to the same food vary widely.