You’re tired. Not just "I stayed up too late watching Netflix" tired, but a bone-deep, heavy exhaustion that makes the walk from the couch to the kitchen feel like a trek up a mountain. You’ve been drinking water like it’s your job, yet your mouth still feels like it’s full of cotton. You might think it’s just the weather, or stress, or getting older.
But honestly? It might be something else.
When we talk about the symptoms of high blood sugar, people usually think of a dramatic medical emergency. They picture someone passing out or being rushed to the ER. In reality, hyperglycemia (the medical term for high blood sugar) is often a quiet, creeping thing. It’s subtle. It’s annoying. It’s your body trying to tell you that the glucose in your bloodstream is trapped and has nowhere to go.
The Science of Why You’re So Thirsty
The first thing most people notice is the thirst. Doctors call this polydipsia.
It’s not a normal thirst. It’s an unquenchable, "I just drank a gallon of water and I’m still parched" kind of feeling. This happens because your kidneys are working overtime. When your blood sugar is high, your kidneys can't reabsorb all that excess glucose. It ends up in your urine, dragging fluids from your tissues along with it.
You’re essentially dehydrating from the inside out.
Then comes the frequent bathroom trips—polyuria. If you’re waking up three times a night to pee, your body is desperately trying to flush out the sugar. It’s a vicious cycle: you drink because you’re thirsty, you pee because of the sugar, and you get thirstier because you’re peeing so much.
That Weird, Foggy Exhaustion
Have you ever felt like your brain was wrapped in bubble wrap?
High blood sugar messes with your energy levels in a way that feels counterintuitive. You have all this sugar (energy) in your blood, but your cells can't get to it. If you have insulin resistance or not enough insulin, the "key" that lets the sugar into your cells is broken.
Your cells are literally starving in a land of plenty.
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This leads to fatigue that doesn't go away with a nap. You might feel "hangry" even after a big meal. Some people describe a specific type of irritability—a short fuse that they can't quite explain. According to the American Diabetes Association, fluctuating glucose levels can directly impact your mood and cognitive function. It’s hard to be nice when your brain is technically lacking its primary fuel source.
Symptoms of high blood sugar you might be ignoring
Most people know about the thirst. Fewer people talk about the blurry vision.
When your blood sugar is high, it can actually change the shape of the lens in your eye. Fluid gets pulled into the lens, causing it to swell. Suddenly, your glasses don't work right. Or you're squinting at the TV.
The good news? This is usually temporary. Once your blood sugar levels stabilize, your vision often returns to normal. But if you let it go for years, that high sugar starts damaging the tiny blood vessels in your retina, leading to permanent damage like diabetic retinopathy.
The "Slow Heal" Problem
Think back to the last time you scraped your knee or got a paper cut. Did it take forever to heal?
High blood sugar affects your circulation and damages your nerves (neuropathy). It also interferes with the way your immune system functions. White blood cells, the "soldiers" of your body, become less effective when swimming in a high-glucose environment.
A small blister on your foot shouldn't stay red and angry for three weeks. If it does, that’s a major red flag.
- Dry, itchy skin: Often caused by poor circulation or dehydration.
- Recurrent infections: Especially yeast infections or skin infections, because yeast feeds on sugar.
- Tingling in the hands or feet: That "pins and needles" feeling that doesn't go away.
The Mystery of Unexplained Weight Loss
It sounds like a dream to some, but losing weight without trying is actually a pretty scary sign of severely high blood sugar.
When your body can’t use glucose for energy, it starts burning fat and muscle for fuel instead. You’re eating, but you’re shrinking. This is more common in Type 1 diabetes, but it can happen in Type 2 if the body is extremely stressed.
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Dr. Anne Peters, a renowned endocrinologist at Keck Medicine of USC, often points out that by the time someone shows up with significant weight loss and extreme thirst, their blood sugar has likely been high for quite a while.
Is it just a "Sugar Crash" or something more?
We’ve all had that post-lunch slump. You eat a giant bowl of pasta, and an hour later, you want to faceplant onto your desk.
That’s a spike and a crash.
But chronic high blood sugar is different. It’s a sustained state of being. You might notice that your breath smells fruity—almost like nail polish remover. This is a sign of ketoacidosis (DKA), a life-threatening complication where your body is producing too many ketones because it can’t use sugar.
If you feel nauseous, have stomach pain, or are breathing rapidly alongside that fruity breath, stop reading this and go to the hospital. Seriously.
The Role of "Hidden" Symptoms
There are some signs that nobody associates with blood sugar.
Take "Acanthosis Nigricans" for example. It’s a fancy name for dark, velvety patches of skin that usually show up in the folds of your neck, armpits, or groin. It’s not dirt. It’s a sign of insulin resistance. Your body is pumping out so much insulin to try and handle the sugar that it causes skin cells to reproduce rapidly, leading to those dark patches.
Then there’s the "Dawn Phenomenon."
You might find that your blood sugar is highest in the morning, even if you haven't eaten since 7 PM the night before. Your liver dumps glucose into your system to help you wake up, but because of your high baseline levels, it pushes you into the danger zone.
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Why context matters
Everyone’s "high" is different.
A "normal" fasting blood sugar is typically between 70 and 99 mg/dL. If you’re consistently hitting 130+ while fasting, or over 180 two hours after eating, you’re in hyperglycemia territory.
However, some people feel symptoms at 150, while others (often called "glucose happy" by some old-school nurses) don't feel a thing even when they’re at 300. This is the "silent killer" aspect of the condition. Just because you don't feel like you have symptoms of high blood sugar doesn't mean the damage isn't happening to your kidneys, heart, and nerves.
What you should actually do about it
If this sounds like you, don't panic. Panic raises cortisol, and cortisol raises blood sugar. Not helpful.
The first step is data. You need to know your numbers.
You can buy a basic glucose monitor at any pharmacy for about twenty bucks. You don't need a prescription. Prick your finger, check your levels when you wake up and again two hours after your biggest meal.
Actionable Next Steps
- Hydrate with water only. Stop the soda, the "healthy" fruit juices, and the sweetened coffee. You need to help your kidneys flush the excess, and adding more sugar is like throwing gasoline on a fire.
- Move your body. You don't need to run a marathon. A 15-minute walk after dinner helps your muscles soak up that excess glucose without needing as much insulin.
- Watch the "Naked" Carbs. If you’re going to eat carbohydrates (bread, rice, fruit), "dress" them with protein or fat. A slice of bread alone will spike you. A slice of bread with peanut butter or avocado will result in a slower, more manageable rise.
- Get an A1c test. This is a blood test that shows your average blood sugar over the last three months. It’s the gold standard for seeing the big picture.
- Check your feet. If you have high sugar, you might not feel a cut or a blister. Make it a habit to check your feet every night before bed.
High blood sugar isn't a moral failing. It's often a mix of genetics, stress, and modern lifestyle factors. The key is catching it before it turns into permanent damage. If your body is sending you these signals—the thirst, the fatigue, the blurry vision—listen to it. It’s the only one you’ve got.
Schedule an appointment with your primary care doctor and ask specifically for a metabolic panel and an A1c test. It’s better to know now than to wonder why you feel so lousy six months from now.