Quick answer
The most common symptoms of high blood sugar are intense thirst, frequent urination (especially at night), fatigue, blurry vision, and wounds that heal slowly; there are also silent signs like dark patches on the neck. In Mexico, 1 in 2 people with diabetes don't know they have it. A fasting glucose of 100 to 125 mg/dL is prediabetes and 126 or higher is diabetes. At AVA Médica you can get checked with no appointment.
Type 2 diabetes has one feature that makes it dangerous: at first, it doesn't hurt. No fever, no discomfort, so it can progress for years without being noticed. In Mexico, 18.4% of adults live with diabetes, and about half of them don't know it.
The good news is that the body does send signals, subtle ones worth recognizing early.
Why diabetes is silent
High blood sugar slowly damages blood vessels and nerves. Because it doesn't cause sharp pain, the first symptoms are easy to blame on tiredness, age, or stress. That's why many people are diagnosed years after it began.
Symptoms of high blood sugar
Once blood sugar is already high, these are the most common symptoms. They can creep in slowly, so many people get used to them:
- Intense thirst, even when you drink water often.
- Urinating a lot, especially at night: waking up two or three times to go.
- Frequent hunger, even shortly after eating.
- Fatigue or sleepiness after meals.
- Blurry vision that comes and goes.
- Weight loss without dieting.
- Infections that keep coming back, like urinary or yeast infections.
5 silent signs worth paying attention to
- Dark patches on the neck or armpits (skin looks "dirty" even when clean).
- Needing to urinate often, especially at night.
- Cuts or scrapes that take longer than usual to heal.
- Tingling or numbness in the hands or feet.
- Extreme fatigue for no clear reason, and constant thirst even when you drink water.
No single sign confirms diabetes on its own, but if several sound familiar, it's a good time to get checked.
How it's detected and what's normal
Checking your blood sugar is simple: a blood test is enough. The two most common tests are fasting glucose and hemoglobin A1c (HbA1c), which reflects your average over the last three months:
| Result | Fasting glucose | Hemoglobin A1c (HbA1c) |
|---|---|---|
| Normal | Below 100 mg/dL | Below 5.7% |
| Prediabetes | 100 to 125 mg/dL | 5.7% to 6.4% |
| Diabetes | 126 mg/dL or higher | 6.5% or higher |
Fasting glucose ranges follow Mexico's official standard NOM-015-SSA2-2010; HbA1c ranges follow the American Diabetes Association. A single high result isn't a diagnosis on its own: the doctor confirms it with another test. The key point is that prediabetes can still be reversed with changes in diet and physical activity.
When high blood sugar is an emergency
If someone with very high blood sugar has confusion, severe drowsiness, vomiting, rapid breathing, or fruity-smelling breath, they need urgent care that same day. It isn't common, but it's worth recognizing.
What you can do today
If any sign sounds like you, don't worry, the important thing is to get checked. At AVA Médica you can have a walk-in visit and, if the doctor recommends it, get your lab work done in the same place, all in a single visit.
This information is general and does not replace a medical consultation. Always consult your doctor for a personalized diagnosis and treatment.