If you’re asking, “What level of blood sugar is dangerous?” you’re making a great move to stay on top of your health. Maybe you’re managing diabetes, helping someone close, or want to know more—like what level of blood sugar is dangerously low or at what level does blood sugar become hazardous. As an endocrinologist, I’ve put together this guide to answer those questions with simple, reliable advice tailored for you. You’ll learn about risky glucose levels, warning signs, what effect high blood sugar has on the body, and practical steps to stay healthy, including tools from DeliverMyMeds to make it easier.
Why Your Blood Sugar Counts
Blood sugar, or glucose, is the fuel behind your daily life—your morning coffee run, your work hustle, and even your cosy evenings. Your pancreas keeps it in check with insulin (lowers glucose) and glucagon (raises it). Normal levels are:
- Fasting (before meals): 70–99 mg/dL (3.9–5.5 mmol/L)
- After meals (1–2 hours): Below 140 mg/dL (7.8 mmol/L)
- A1C (2–3 month average): Below 7%
Health note: A1C tracks your average glucose over months, giving your doctor a big-picture view of control. But when is A1C dangerous? Anything above 8% signals trouble, as we’ll explore.
When levels swing too high or too low, you might feel off or risk bigger problems. Let’s dive into what an unsafe blood sugar level is and how to handle it.
What Makes Blood Sugar Levels Dangerous?
An unsafe blood sugar level can be too high (hyperglycemia) or too low (hypoglycemia). Let’s break down at what level does blood sugar become dangerous, including what blood sugar level can kill you if ignored.
High Blood Sugar: When Is It Risky?
High blood sugar builds when insulin can’t keep up, often from diabetes or lifestyle factors. You might wonder, what effect does high blood sugar have on the body? It can strain organs like your heart, kidneys, and eyes, causing long-term damage.
Key levels:
- 240 mg/dL (13.3 mmol/L) or higher: Staying here risks diabetic ketoacidosis (DKA) or dehydration emergencies (HHS).
- 300 mg/dL (16.7 mmol/L) or more: A critical zone needing immediate care, especially with symptoms.
- Is a 500 blood sugar level dangerous? Yes—it’s life-threatening, potentially leading to coma or worse.
A1C above 8%: A dangerous A1C reflecting months of highs, increasing chances of nerve damage or blindness.
Health note: DKA (common in type 1 diabetes) creates harmful ketones from fat breakdown, while HHS (more in type 2) causes severe dehydration. Both can be fatal without hospital treatment.
Signs to watch:
- Constant thirst or lots of bathroom trips
- Feeling wiped out or foggy
- Blurry vision or stubborn headaches
- Severe cases: nausea, fast breathing, confusion
What to do: Call your doctor if your blood sugar hits 240 mg/dL and doesn’t budge or you feel sick. For type 1 diabetes, test ketones at home. The Freestyle Libre 2 from DeliverMyMeds tracks levels in real time, alerting you to highs before they hit dangerous zones like 500 mg/dL. Follow your doctor’s plan for insulin or meds.
Low Blood Sugar?
You might ask, what level of blood sugar is dangerously low? Hypoglycemia happens when glucose drops, leaving your brain and body short on fuel—often from insulin, meds, or missing meals.
Key levels:
- Below 70 mg/dL (3.9 mmol/L): Time to act to prevent a deeper drop.
- Below 55 mg/dL (3.1 mmol/L): Serious, affecting your thinking or balance.
Health note: Hypoglycemia unawareness (missing symptoms) can sneak up in long-term diabetes. Regular checks keep you safe.
Signs to watch:
- Shakiness, sweating, or a racing heart
- Feeling starved or snappy
- Trouble focusing or slurring words
- Severe cases: blacking out or seizures
What to do: Eat 15 grams of fast-acting carbs (half a cup of juice, a tablespoon of honey, or glucose tablets). Recheck in 15 minutes. If it’s still below 70 mg/dL or you feel bad, eat another 15 grams and get help if needed. The Dexcom G6 from DeliverMyMeds warns you of lows early, so you can avoid dangerous drops. Ask about a glucagon kit for emergencies.
What Causes Blood Sugar Fluctuations?
Curious as to why your levels are high or low. Here are common triggers:
High blood sugar causes:
- Missing insulin or diabetes meds
- Eating big carb meals or sugary drinks
- Stress or illness (like the flu)
- Not staying active
Low blood sugar causes:
- Too much insulin or certain pills
- Skipping snacks or meals
- Hard workouts without extra food
- Alcohol without eating
Health note: Morning highs (dawn phenomenon) come from overnight hormone surges. Your doctor can adjust your routine to smooth these out.
Spotting these patterns helps you avoid unsafe blood sugar levels.
Why Dangerous Levels Matter
Ignoring risky blood sugar hurts your body. What effect does high blood sugar have on the body long term? It can lead to:
High blood sugar:
- Right away: DKA or HHS, needing urgent hospital care.
- Over time: Heart issues, kidney damage, nerve pain, vision loss.
- Low blood sugar:
- Right away: Confusion, falls, or passing out.
- Over time: Frequent lows might make you feel anxious or forgetful.
Health note: Highs damage tiny blood vessels (like in your eyes), while lows stress your brain. Yearly checkups spot problems early.
You can prevent these with simple habits and the right tools.
Your Everyday Plan for Healthy Blood Sugar
Here’s how to keep your levels steady, with tips that fit your life:
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Stay on Top of Checking:
Test with a glucometer or CGM in the morning, before meals, or after exercise.
- The Omnipod 5 insulin pump from DeliverMyMeds pairs with CGMs to adjust insulin for you, keeping levels safe.
- Health tip: Log your numbers to share with your doctor—it helps them tweak your plan.
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Eat Smart, Enjoy Food:
- Build meals with half veggies (like zucchini), a quarter protein (like eggs), and a quarter whole grain (like brown rice).
- Love a treat? Pair it with yoghurt or nuts and a drink of protein shake to ease sugar spikes.
Health tip: Fibre-rich foods (like lentils) slow glucose rises—ask a dietitian what works for you.
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Keep Up with Meds:
- Set smartphone reminders to ensure the timely administration of insulin or oral medications.
- If you experience unusual side effects from medications, consult your physician for potential adjustments.
Medical tip: Certain oral medications are more effective and better tolerated when taken with food to minimize gastrointestinal discomfort.
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Be Prepared:
- Carry juice or glucose tabs everywhere—bag, car, work.
- Wear a medical ID and teach your family about glucagon for bad lows.
- Health tip: Glucagon needs a prescription—it’s a lifesaver for severe lows.
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Lean on Your Doctor:
- Visit regularly to keep your plan working.
- Ask about yearly tests (eyes, kidneys) to stay healthy.
Health tip: Diabetes educators can show you easy ways to count carbs or plan meals.
When to Call for Medical Help
- High blood sugar: If it’s over 240 mg/dL for hours, or you’re vomiting, confused, or breathing fast (especially at 500 mg/dL).
- Low blood sugar: If carbs don’t help after two tries, or you can’t stay alert.
Health note: Fruity breath (DKA) or feeling super sleepy (HHS) are signs to act fast. Don’t wait if something feels wrong.
You’re Stronger Than Your Numbers
What level of blood sugar is dangerous? Above 240 mg/dL or below 55 mg/dL calls for action, and levels like 500 or under 40 are emergencies. When is A1C dangerous? Over 8% means it’s time to get help. But you’re in charge. With tools from DeliverMyMeds, balanced meals, and a bit of planning, you can feel your best.
Your doctors are your teammates—call them with questions. You’re doing great just by learning more.
References:
American Diabetes Association, Standards of Care
Endocrine Society, Clinical Guidelines
National Institutes of Health, Diabetes Resources
Disclaimer: This guide is for information only. Always talk to your doctor for personal health advice.
