Knowing what to do when blood sugar is high helps you act quickly and avoid complications. Hyperglycemia means elevated plasma glucose, which can stress organs and worsen dehydration. Responding early limits risk, stabilizes energy, and protects long-term health. This guide explains signs, safe first steps, thresholds, and when to seek urgent care.
Use your personalized diabetes action plan if you have one. If not, the steps below can help you navigate short-term spikes while you arrange professional guidance. We include food and drink tips, monitoring advice, and emergency red flags.
Key Takeaways
- Recognize early signs: thirst, frequent urination, fatigue, blurry vision.
- Confirm with a meter, hydrate, move safely, and recheck.
- Know danger zones and when to call or visit urgent care.
- Tailor actions to illness, pregnancy, and your care plan.
What Is Hyperglycemia? Signs and Clinical Risks
Hyperglycemia is high blood glucose that exceeds your target range. Common signs include intense thirst, frequent urination, dry mouth, headache, and blurry vision. You may also notice nausea, abdominal discomfort, or difficulty concentrating. These symptoms develop because excess glucose draws water from tissues and increases urine output.
It helps to recognize what are 5 signs your blood sugar is too high. Typical examples include thirst, polyuria (peeing often), fatigue, blurred vision, and headaches. Left untreated, severe spikes can lead to diabetic ketoacidosis (DKA, a high-ketone emergency) or hyperosmolar hyperglycemic state (HHS, profound dehydration without ketones). For a plain-language overview of risks, see the NIDDK guidance reviewed by U.S. experts.
For background reading on how spikes start and progress, see Sugar High for context on triggers. Cognitive effects also matter; brief fluctuations can impair focus, as discussed in Blood Sugar and Brain Function for safety considerations.
What to Do When Blood Sugar Is High
Confirm the reading with a fingerstick meter if your CGM rises rapidly or shows questionable data. Wash and dry your hands first to avoid contamination. Note the time, last meal, medications, and activity so you can see patterns later.
Follow your care plan’s correction steps if you have one. If you use insulin, do not change doses without guidance unless your plan tells you exactly how. Hydrate with water, avoid sugary beverages, and consider a short, easy walk if you are not ill and have no ketones.
Recheck glucose in about 1–2 hours to confirm a downward trend. If numbers remain high, look for causes such as missed doses, a failing infusion set, a spoiled insulin vial, or an oncoming illness. For urgent scenarios and decision points, the article Acute Hyperglycemia outlines next steps to discuss with your clinician.
Fast But Safe Short-Term Steps
Some actions can nudge glucose down without overshooting. First, hydrate with water to support kidney clearance. Second, use light movement like a 10–15 minute walk if you have no ketones or illness symptoms. Third, choose a small, low-carbohydrate snack only if you are hungry and trending down.
Ask your care team about how to reduce blood sugar level immediately in a safe, individualized way. People using insulin or insulin secretagogues face hypoglycemia risk if they stack actions without a plan. Avoid intense exercise during a spike if you suspect ketones; vigorous activity can worsen ketosis. Stress can raise glucose, so learn calming techniques in Stress on Diabetes to reduce sympathetic spikes.
Move, Hydrate, Recheck
Short activity, like gentle walking or household tasks, can improve insulin sensitivity and help glucose shift into muscle. Pair movement with steady water intake and a protein-forward snack only if you feel hungry. Avoid concentrated carbohydrate while you are high. Recheck with a meter within 60–120 minutes to monitor progress and prevent over-correction. If you wear a pump or pen, inspect your delivery device for leaks or blockages. For troubleshooting spoiled insulin and storage limits, see Insulin Storage Dangers for temperature guidance.
When Numbers Are Dangerous: Thresholds and Actions
Knowing your thresholds reduces panic and improves decisions. Many care plans flag 240 mg/dL (13.3 mmol/L) as a point to check ketones, especially in type 1 diabetes or during illness. Persistent readings over 300 mg/dL increase the chance of dehydration and symptoms.
Your clinician can define what is a dangerous level of blood sugar for your situation. In general, any sustained value above 400 mg/dL (22.2 mmol/L) warrants urgent attention, and levels near 600 mg/dL (33.3 mmol/L) may signal HHS, a medical emergency. For evidence-based thresholds and crisis features, review the ADA hyperglycemia overview before refining your action plan.
Consider reviewing dose adjustment principles in Adjust Insulin Dose to discuss with your clinician. Avoid self-directing medication changes unless explicitly taught to do so.
Food and Drink Choices During a Spike
Food can help or hinder recovery from a spike. Select low-carbohydrate, high-fiber foods such as non-starchy vegetables, eggs, fish, tofu, or nuts. Pairing protein with a small portion of slow-digesting carbohydrate can steady levels once you are trending down.
If you are choosing what foods lower blood sugar immediately, emphasize water-rich vegetables and modest protein portions rather than quick sugars. Drink water, unsweetened tea, or coffee without sugar; avoid juices and regular soda. For practical snack ideas with healthy fats and fiber, see Best Nuts for Diabetics as part of a balanced approach.
Tip: If nighttime highs are common, prepare a consistent evening routine. Many find that earlier dinners, gentle walks, and adequate hydration help reduce overnight variability without aggressive adjustments.
Special Situations: Illness, Steroids, and Pregnancy
Fever, infections, and corticosteroids often drive glucose higher. Sick-day plans usually include more frequent checks, hydration, and ketone testing. Contact your care team sooner if you have vomiting, diarrhea, or cannot keep fluids down.
Discuss what to do when blood sugar is high during pregnancy with your obstetric and diabetes providers. Targets are often tighter to protect both parent and fetus. Test more often, hydrate, and follow your individualized correction instructions. For broader educational reading across conditions, browse Diabetes to support conversations with your clinicians.
Meter Accuracy, Charts, and Monitoring Plans
Accurate readings drive good decisions. Calibrate your approach by comparing your CGM with a reliable fingerstick during stable periods. Replace test strips on time and store them properly for consistent results. If in doubt, confirm with two tests separated by a few minutes.
Many readers ask for a normal blood sugar levels chart to place readings in context. The table below lists commonly referenced targets; your care plan may differ. Use this as a conversation starter with your clinician.
| Timing | Typical Target (mg/dL) | Typical Target (mmol/L) |
|---|---|---|
| Fasting/pre-meal | 80–130 | 4.4–7.2 |
| 1–2 hours after meal | Less than 180 | Less than 10.0 |
| Bedtime | 90–150 | 5.0–8.3 |
For meter selection and tracking, see OneTouch Verio Flex Meter for device features to discuss with your team. For consistent readings, compatible supplies such as Contour Next Test Strips may support your monitoring plan. For frequency guidance and pattern analysis, review Monitor Blood Sugar before setting reminders.
When to Seek Emergency Care
Severe symptoms, vomiting, heavy breathing, fruity breath, confusion, or inability to keep fluids down require urgent evaluation. If you measure large ketones or suspect infusion failure and cannot correct it quickly, seek immediate care. Bring your meter or CGM, medication list, and recent readings.
Know what to do for blood sugar over 500 what to do situations: focus on hydration, checking ketones if advised, and urgent medical assessment. Extremely high levels raise the risk of DKA or HHS even in people without type 1 diabetes. If high readings persist despite your usual correction steps, ask whether insulin potency, delivery problems, or infection are factors. For device and storage pitfalls, scan Insulin Storage Dangers to rule out temperature-related failures.
For comprehensive symptom and management guidance reviewed by experts, see the ADA hyperglycemia overview before finalizing your emergency checklist.
Recap
Respond early to hyperglycemia by confirming the reading, hydrating, moving safely, and rechecking. Know your thresholds, and escalate when symptoms or numbers cross danger lines. Use your care plan, and involve your clinician when spikes persist or worsen.
Note: Keep a simple log of readings, actions, and suspected causes. Small patterns over a week often reveal clear next steps to discuss at your next appointment.
This content is for informational purposes only and is not a substitute for professional medical advice.
