You just looked down at your glucose monitor or a fresh lab report and saw that number staring back: 89 mg/dL. It feels specific. It’s not 100, but it’s not 70 either. Naturally, you’re wondering, is 89 low for blood sugar, or are you right where you need to be?
Honestly, it depends on who you are.
If you’re a healthy adult without diabetes, 89 is a dream number. It’s basically the "Goldilocks" zone of metabolic health. You’re fueled, your brain is firing, and your pancreas isn't screaming for help. But if you’re living with Type 1 or Type 2 diabetes and you’re used to seeing numbers in the 150s, 89 might feel like a shaky, sweaty disaster waiting to happen. Context is everything here. We need to stop looking at blood sugar like a static test score and start looking at it as a moving target.
The Reality of the 89 mg/dL Reading
For most of the population, a fasting blood sugar between 70 and 99 mg/dL is considered "normal" by the American Diabetes Association (ADA). So, sitting at 89 puts you squarely in the middle of that healthy bracket. You’re fine. Better than fine, actually. You’re metabolically flexible.
But let’s get weird for a second.
What if you just ate a massive bowl of pasta two hours ago and you're at 89? That might actually be a sign of reactive hypoglycemia, where your body overreacts to carbs and pumps out way too much insulin, crashing you down faster than a lead weight. Or, what if you’re pregnant? The stakes change. The targets tighten.
The medical community, including experts like Dr. Peter Attia, often suggests that lower-normal fasting glucose—specifically in the 80s—is a strong indicator of longevity and insulin sensitivity. When your body can maintain an 89 without effort, it means your "metabolic machinery" is humming along. You aren't forcing your pancreas to overwork, and you aren't marinating your organs in excess sugar.
Why You Might Feel "Low" When You Aren't
Have you ever felt lightheaded or shaky even though your monitor says 89? This is a real phenomenon called "false hypoglycemia" or "relative hypoglycemia."
👉 See also: How do you play with your boobs? A Guide to Self-Touch and Sensitivity
It happens most often to people who have lived with high blood sugar for a long time. If your body is used to 200 mg/dL, it resets its "normal" thermostat. When you finally get your levels down to a healthy 89, your brain panics. It thinks you’re starving. It triggers a shot of adrenaline. You get the shakes. You get irritable. You might even start sweating.
It sucks. It really does. But your blood sugar isn't actually dangerously low; your body is just throwing a tantrum because it misses the sugar high it grew accustomed to.
Understanding the "Normal" Range vs. The "Optimal" Range
Most doctors look at 99 as the cutoff. If you’re at 100, you’re "prediabetic." If you’re at 99, you’re "healthy."
That’s kinda silly, right? A single point shouldn't change your entire medical identity.
In the functional medicine world, experts often argue that we should aim for "optimal," not just "normal." While is 89 low for blood sugar is technically answered by a "no," many clinicians prefer their patients to sit between 75 and 85 mg/dL while fasting.
Why? Because glycation happens.
Glycation is basically what happens when sugar sticks to proteins in your body. It’s like a slow-motion browning effect, similar to a crust forming on bread. The higher your average blood sugar, the more glycation occurs, leading to inflammation and aging. By staying at 89, you are significantly reducing the rate of this "internal rusting" compared to someone sitting at 105.
✨ Don't miss: How Do You Know You Have High Cortisol? The Signs Your Body Is Actually Sending You
When 89 Becomes a Concern
There are specific scenarios where 89 might actually require a bit of caution.
- The "Downswing" Effect: If you were at 250 mg/dL twenty minutes ago and now you're at 89, you are dropping too fast. The velocity of the drop matters more than the number itself. Rapid shifts in blood glucose can cause neurological symptoms even if you stay within the "normal" range.
- Medication Interactions: If you take insulin or certain sulfonylureas (like glipizide), 89 is getting close to the "danger zone" of 70 mg/dL. If you still have active insulin in your system (what docs call "insulin on board"), 89 could turn into 50 very quickly.
- Exercise: If you're about to go for a 10-mile run and you're at 89, you probably need a snack. High-intensity exercise can tank your glucose if you don't have enough glycogen stores or recent food intake to back it up.
The Role of the A1c and CGM Data
Looking at a single 89 is like looking at one frame of a two-hour movie. It doesn't tell the whole story.
To really understand if 89 is "good" for you, you have to look at your Hemoglobin A1c. This test measures your average blood sugar over the last three months. If your A1c is 5.2% and you see an 89, you’re in the clear. You’re a rockstar.
However, if your A1c is 6.5% (the threshold for diabetes) and you see an 89, that’s an outlier. It might mean you’re experiencing huge "swings"—high highs and low lows. That variability is actually more damaging to your blood vessels than a steady, slightly high number. This is where Continuous Glucose Monitors (CGMs) like the Dexcom or Freestyle Libre come in. They show the "waves." If your 89 is the bottom of a gentle wave, great. If it’s the bottom of a jagged cliff, we have a problem.
Does Age Change the Answer?
Age definitely matters. For an 80-year-old, we actually want blood sugar to be a little higher.
The Department of Veterans Affairs and other geriatric organizations often suggest more relaxed targets for seniors. Why? Because the risk of a "low" (hypoglycemia) is way more dangerous for an older person than the long-term risk of a "high." A fall caused by dizziness from an 89 mg/dL reading (if it’s dropping) can lead to a broken hip. In the elderly, a "safe" fasting number might be closer to 110 or 120.
Conversely, in young, healthy athletes, seeing a blood sugar of 89 after a workout is standard. Their bodies are incredibly efficient at clearing glucose from the blood and shoving it into the muscles where it belongs.
🔗 Read more: High Protein Vegan Breakfasts: Why Most People Fail and How to Actually Get It Right
Common Myths About "Low" Blood Sugar
People hear the word "hypoglycemia" and get spooked. Let’s clear some things up.
- Myth: You need to eat sugar immediately if you're at 89. Nope. Unless you are on insulin and dropping fast, your liver is perfectly capable of making its own sugar (gluconeogenesis) to keep you stable.
- Myth: 89 means you’re going to faint. Highly unlikely. Clinical hypoglycemia is typically defined as anything under 70 mg/dL. Most people don't experience true cognitive impairment until they hit the 50s.
- Myth: 89 is too low for a "fasting" test. Standard lab ranges usually go down to 65 or 70. 89 is comfortably above the basement.
Dietary and Lifestyle Factors That Influence an 89 Reading
What you did yesterday affects that 89 today.
If you did a heavy leg day at the gym yesterday, your muscles might be soaking up extra glucose to repair themselves, keeping your number at a steady 89. If you had a poor night's sleep (less than 6 hours), your cortisol might actually spike your sugar higher than 89 tomorrow morning.
Alcohol is another big one. If you had a couple of glasses of wine last night, your liver was busy processing the toxin (alcohol) instead of releasing glucose. This can lead to a lower-than-normal morning reading. So, if you're usually 105 and suddenly you're 89 after a night out, don't celebrate your "new health"—it's just your liver being preoccupied.
Practical Steps to Manage Your Levels
If you are seeing 89 and feeling "off," or if you want to maintain this healthy level without dipping lower, there are some very specific things you can do.
- Check your electrolytes. Often, the "shakiness" people associate with low blood sugar is actually a lack of sodium, magnesium, or potassium. This is especially true for people on keto or low-carb diets.
- Prioritize protein. If you are worried about 89 becoming 60, make sure your meals are anchored in protein. Protein stimulates a hormone called glucagon, which acts as the "brake" for insulin. It keeps you level.
- Watch the caffeine. Too much coffee can mimic the feelings of low blood sugar—heart racing, anxiety, jitters—even when your sugar is a perfect 89.
- Hydrate, but don't overdo it. Dehydration can make blood sugar readings appear artificially high because the glucose is more concentrated in less blood volume.
Final Actionable Insights
If your blood sugar is 89, here is your checklist:
- Assess how you feel. If you feel fine, you are fine. Don't let the number create phantom symptoms.
- Look for patterns. Is 89 your "normal," or is this a sudden drop? Use a log or an app to track it over a week.
- Verify with your doctor if you're on meds. If you take diabetes medication, mention the 89 to your provider. They might want to tweak your dosage to ensure you don't dip into the 60s at night.
- Test your "Post-Prandial" levels. Check your sugar two hours after a meal. If you go from 89 fasting to 180 after lunch and then back to 89, your body is struggling with "glucose spikes," which are inflammatory.
- Keep a "rescue snack" if you have Type 1. Even though 89 is safe, if you're active, keep 15 grams of fast-acting carbs nearby just in case.
Basically, 89 is a badge of metabolic honor for most people. It’s the sweet spot where your body is fueled but not overwhelmed. Stay there if you can. Just make sure the journey to that 89 isn't a rollercoaster ride. Consistent stability is always the goal.