High blood sugar, or hyperglycemia, is more common than many realize, and it often develops silently.
Early symptoms can be subtle, such as thirst, tiredness, or blurry vision, and are easy to dismiss as everyday issues.
However, when left untreated, consistently high blood sugar can damage blood vessels, nerves, and vital organs, leading serious complications like kidney disease, heart problems, and vision loss.
1. Excessive Thirst
Your kidneys help regulate blood sugar by filtering and reabsorbing glucose, so healthy urine contains little to no glucose. When blood sugar is too high, the kidneys work harder to remove the excess, pulling fluids from body tissues to dilute and flush out the sugar. This leads to dehydration and increased thirst. Persistent dry mouth or feeling very thirsty, no matter how much you drink, can be a sign of hyperglycemia.
2. Increased Urination
More frequent trips to the bathroom, especially at night, can be a sign of high blood sugar. This happens because your kidneys are drawing extra water out of your tissues to dilute the extra sugar in your blood and get rid of it through urine.
3. Increased Hunger
When there’s extra sugar in your bloodstream, it means that your body cannot use it for fuel. Your cells end up starved of energy, which causes you to feel more hungry than usual. However, what you eat matters because the more carbohydrates you consume, the higher your blood sugar will be.
4. Blurry Vision
High sugar levels force the body to pull fluid from your tissues, including the lenses of your eyes. This can affect your ability to focus on what you’re looking at and may lead to blurry vision.
5. Fatigue
Normally, your cells absorb blood sugar for energy. When sugar stays in the blood instead of being taken to your cells, your cells don’t have enough. This can make you feel sluggish or fatigued—especially after you’ve eaten a high-carb meal.
6. Infections
If your immune system is not working well as a result of high blood sugar and stress on the body, you might be more likely to get infections. It’s also thought that some kinds of bacteria actually live best in high-sugar environments, so they might thrive in your body when your levels are high.
Since yeast feeds on sugar, having elevated blood sugar levels can lead to an overgrowth of yeast. For people with a vagina, frequent yeast infections are common if they have high blood sugar levels.
7. Skin Conditions
Dry, itchy skin, and wounds or cuts that are slow to heal can be a sign of hyperglycemia. Another sign that points to insulin resistance is acanthosis nigricans, a condition in which thick, velvety patches form in the folds or creases of areas like the neck.
8. Worsened Mood
Researchers also think it’s possible that your blood sugar levels might affect your mood. While more research is needed, there is some evidence that higher blood sugar levels after meals in people with type 2 diabetes might be linked to certain negative mood symptoms, like irritability.
Other studies have suggested that having higher blood sugar levels might be linked to feelings of anger and sadness among people with diabetes.
9. Stomach Pain
Chronic hyperglycemia can lead to nerve damage in the stomach (gastroparesis or delayed gastric emptying). This condition can cause nausea and very slow digestion. Stomach pain can also be a sign of diabetic keto acidosis, a medical emergency that needs to be treated right away.
10. Unintended Weight Loss
Unintentional weight loss is an important sign of elevated blood sugar, particularly in kids who are drinking and urinating often. Many children diagnosed with type 1 diabetes lose weight before they’re diagnosed because their bodies cannot use the sugar in the bloodstream for fuel.
11. Numbness
Nerve damage in the extremities (peripheral neuropathy), can happen over time in people with high blood sugar. It causes symptoms like numbness, tingling, or pain in the hands, feet, or legs.