High Blood Sugar Symptoms: 9 Warning Signs You Shouldn't Ignore

18 Sep 2025 By Pankaj Shah, M.D.

High Blood Sugar Symptoms: 9 Warning Signs You Shouldn't Ignore

High blood sugar, also known as hyperglycemia, occurs when there's too much glucose in the blood. This can happen for a variety of reasons, including diabetes, stress, illness, and certain medications. Recognizing the symptoms of high blood sugar is crucial for managing your health and preventing potentially serious complications. This article will explore nine key warning signs you shouldn't ignore, offering practical insights and actionable information.

High blood sugar isn't always immediately dangerous, but prolonged or extremely high levels can lead to serious health problems such as: Diabetes Management A Practical Guide To Daily Blood Sugar Control

Diabetic Ketoacidosis (DKA): A life-threatening condition that occurs when the body produces high levels of blood acids called ketones.
Hyperosmolar Hyperglycemic State (HHS): Another dangerous condition causing severe dehydration and can lead to coma.
Long-Term Complications: Over time, consistently high blood sugar can damage organs like the heart, kidneys, eyes, and nerves.

Therefore, early detection and management are essential.

1. Frequent Urination (Polyuria)

One of the most common early signs of high blood sugar is frequent urination, also known as polyuria. When your blood sugar levels are elevated, your kidneys try to eliminate the excess glucose through urine. This leads to an increased need to urinate, especially at night.

Why it happens: The kidneys work overtime to filter and remove excess glucose from the blood.
What to watch for: Waking up multiple times during the night to urinate, feeling the urge to go even shortly after urinating.

This symptom is often one of the first noticeable signs, particularly if it disrupts your normal routine. It's important to monitor the frequency and report it to your healthcare provider.

2. Increased Thirst (Polydipsia)

Closely linked to frequent urination is increased thirst, or polydipsia. As your body loses fluids through excessive urination, it becomes dehydrated, triggering the thirst mechanism.

Why it happens: The body attempts to compensate for fluid loss due to increased urination.
What to watch for: Feeling constantly thirsty, drinking more fluids than usual without relief, dry mouth.

Increased thirst often accompanies frequent urination, creating a cycle. It's crucial to drink plenty of water to stay hydrated, but also address the underlying cause of the thirst by monitoring blood sugar levels.

3. Unexplained Fatigue and Weakness

Fatigue and weakness are common symptoms of high blood sugar because glucose isn't efficiently entering your cells to provide energy.

Why it happens: Cells are starved of glucose, which they need for energy. This results in generalized fatigue.
What to watch for: Feeling unusually tired even after sufficient rest, experiencing weakness or difficulty concentrating.

Even if you are sleeping normally, persistent fatigue can be a sign that your body isn't processing glucose correctly. Differentiating this from everyday tiredness is crucial.

4. Blurred Vision

Blurred vision can occur when high blood sugar causes fluid to shift in and out of the lenses of your eyes, affecting their ability to focus.

Why it happens: Changes in fluid levels within the eye lens alter its shape and refractive power.
What to watch for: Difficulty focusing, seeing halos around lights, experiencing fluctuating vision clarity.

This symptom can come on suddenly and can sometimes fluctuate depending on the blood sugar level. Chronic high blood sugar can also lead to more severe eye problems like diabetic retinopathy.

5. Slow-Healing Cuts and Sores

High blood sugar can impair the body's natural healing processes, leading to slow-healing cuts and sores.

Why it happens: High glucose levels affect the function of white blood cells, which are essential for wound healing, and can also impair circulation.
What to watch for: Cuts, bruises, or sores that take longer than usual to heal, frequent infections.

This is particularly noticeable if minor injuries become infected or take weeks, rather than days, to heal. Any persistent or recurring infections should also raise concern.

6. Increased Susceptibility to Infections

Elevated blood sugar levels can weaken the immune system, making you more susceptible to infections. A Simple Guide To Your First Fasting Blood Sugar Test

Why it happens: High glucose environments can foster bacterial and fungal growth, while also impairing the function of immune cells.
What to watch for: Frequent urinary tract infections (UTIs), yeast infections, skin infections, or respiratory infections.

Women might notice recurrent yeast infections, while others may experience frequent colds or flu-like symptoms.

7. Numbness or Tingling in Hands and Feet (Neuropathy)

Prolonged high blood sugar can damage nerves, leading to a condition called diabetic neuropathy. This often presents as numbness, tingling, or burning sensations in the hands and feet.

Why it happens: High glucose levels damage the small blood vessels that supply nerves, leading to nerve damage.
What to watch for: Pins-and-needles sensation in the extremities, burning or shooting pain, loss of sensation.

While this is typically a long-term complication, early symptoms should not be ignored. If you experience these sensations, prompt medical evaluation is necessary.

8. Dry and Itchy Skin

Dry and itchy skin can also be a symptom of high blood sugar. This occurs due to dehydration and impaired circulation.

Why it happens: Dehydration from frequent urination leads to reduced skin moisture, and impaired circulation can affect skin health.
What to watch for: Persistent itching, flaky skin, and areas of thickened or discolored skin.

While there could be many other reasons for dry skin, if it occurs in conjunction with other symptoms listed here, it might be related to elevated blood sugar.

9. Unexplained Weight Loss

Although less common, unexplained weight loss can occur in individuals with uncontrolled diabetes or high blood sugar. This is because the body is unable to use glucose for energy, and instead starts breaking down muscle and fat.

Why it happens: Body uses fat and muscles to produce energy, which results in weight loss, because glucose does not reach cells.
What to watch for: Losing a noticeable amount of weight without changes in diet or exercise.

This symptom is more often associated with Type 1 diabetes but can occur in uncontrolled Type 2 diabetes as well.

When to Seek Medical Attention

It's important to consult a healthcare professional if you experience one or more of these symptoms, especially if you have risk factors for diabetes, such as: Why Is My Morning Blood Sugar So High The Dawn Phenomenon

Family history of diabetes
Overweight or obesity
Physical inactivity
High blood pressure or cholesterol
History of gestational diabetes

Your doctor can perform a blood sugar test to determine if your levels are elevated and recommend appropriate management strategies.

Note: This table offers general guidance and does not substitute professional medical advice.

In summary, recognizing the early warning signs of high blood sugar and seeking prompt medical attention are critical steps in managing your health. By being vigilant and proactive, you can prevent complications and maintain a higher quality of life.