What Are the Signs of High and Low Blood Sugar?

We all know how important it is to keep our blood sugar levels within a healthy range. May it be high blood sugar or low blood sugar, both can create complications and health problems. The American Diabetes Association (ADA) in general recommends maintaining blood sugar levels between 80 and 130 milligrams per decilitre (mg/dL) before meals and less than 180 mg/dL two hours after meals.

Hyperglycemia (high blood sugar) or hypoglycemia (low blood sugar) can affect diabetics as well as non-diabetic people. Hence, it is extremely important to know the symptoms and causes of both to prevent them from happening

Symptoms of Hyperglycemia and Hypoglycemia

The symptoms differ depending on whether you have hyperglycemia or hypoglycemia. Thus, understanding the signs of high and low blood sugar should be essential for both diabetics and their friends and families. The more prepared you are to notice the signs of both high and low levels, the better able you will be to rapidly and effortlessly bring them back within a normal range.

Here’s a chart that highlights the symptoms of high and low blood sugar.



Extreme thirst


Dry mouth



Trouble in concentrating



Frequent urination


Blurry vision

Fast heartbeat





Shortness of breath


Let us now understand in detail what the causes of hyperglycemia and hypoglycemia are, so that we can learn how to prevent and treat them.

What is Hyperglycemia?

Hyperglycemia means there is too much sugar in the blood than the normal range. This happens when the body lacks the hormone called insulin which transports glucose into the blood or if the body is unable to utilise the insulin properly.

Hyperglycemia is usually associated with diabetes, but there are some other causes as well which may cause high blood sugar. When hyperglycemia is associated with diabetes, it may cause vomiting, excessive hunger and thirst, blurred vision, rapid heartbeat, frequent urination, shortness of breath and weakness.

Causes of Hyperglycemia

Hyperglycemia is blood glucose greater than 125 mg/dL (milligrams per decilitre) while fasting and if the blood glucose is greater than 180 mg/dL one to two hours after eating. You are at risk of getting hyperglycemia, if you are overweight, have a family history of type 2 diabetes, high blood pressure or cholesterol, polycystic ovarian syndrome (PCOS) or have a history of gestational diabetes.

Apart from diabetes, the other possible causes of hyperglycemia are −

  • Cushing syndrome − An endocrine condition that causes insulin resistance.

  • Pancreatic diseases like cystic fibrosis, pancreatitis and pancreatic cancer.

  • Medications like diuretics, beta-blockers, birth control pills or certain steroids.

  • Surgery or trauma

  • Gestational diabetes − It is extremely rare and may happen during pregnancy due to decreases insulin sensitivity.

Hyperglycemia in Diabetics

Diabetics may develop hyperglycemia if the dose of insulin or other oral diabetes medication is not helpful or the body is not able to utilize the natural insulin effectively. If the amount of carbohydrates consumed is not balanced with the amount of insulin your body can make, then it may result in high blood sugar.

Additionally, if you are diabetic and are less active or have physical or emotional stress, you are at a high risk of getting hyperglycemia. If a diabetic person develops the dawn phenomenon wherein a surge of hormones is produced every morning around 4 am to 5 am, it may affect the body and cause high blood sugar.

If hyperglycemia is not treated in people with type 1 diabetes, it may develop into ketoacidosis. Here, ketones, which are toxic acids, build up in the blood and may create an emergency that, can lead to coma or death. The early symptoms of hyperglycemia are increased thirst or hunger, blurred vision, headache and frequent urination. Moreover, there are some other symptoms like weight loss, fatigue, slow healing of cuts and sores as well as vaginal and skin infections.

Prevention of Hyperglycemia

You can prevent hyperglycemia by incorporating certain lifestyle changes in your daily life. You can consult your healthcare provider and design the best meal plan to work with your diabetes or to keep your blood sugar levels in the desired range.

A daily activity plan inclusive of exercises to help to lower blood sugar can help to maintain a healthy weight and thereby blood sugar levels. One needs to completely avoid smoking and limit alcohol intake which may cause affect blood sugar levels considerably.

What is Hypoglycemia?

After eating a meal or consuming a beverage, insulin which is produced by the pancreas, allows sugar to enter the body cells so that it can be used for energy. However, if there is too much insulin in the bloodstream, it leads to a drop in blood sugar which is termed hypoglycemia. Low blood sugar may happen when you don't eat for longer periods.

In hypoglycemia, there isn't enough glucose left in the bloodstream to supply energy to the organs, muscles and tissues. When the glucose level drops too low, the body releases the epinephrine (adrenaline) hormone which can cause sweating, shaking, anxiety and irritability. People with sugar levels lower than 70 mg/dL are at a high risk of getting hypoglycemia.

Causes of Hypoglycemia

Generally, hypoglycemia is associated with diabetes, but it may also occur due to certain medications like steroids, birth control pills, aspirin, blood pressure medicines and some antibiotics. Hypoglycemia may also occur in non-diabetics in certain medical conditions like a pancreatic tumor, adrenal gland disorders or hepatitis as the pancreas may produce more insulin than required. Other causes may include high alcohol intake on regular basis, increased physical activities or excessive consumption of refined carbohydrates in form of white bread, pasta or pastries.

If a person is diabetic, hypoglycemia may occur when there is too much glucose in the bloodstream due to diabetes medication. The most common signs of hypoglycemia are shaking, sweating, excessive hunger, rapid heartbeat, paleness, fatigue, tingling or numbness, dizziness, irritability and difficulty in concentration. If it’s not treated in time, it may also cause loss of coordination, inability to complete routine tasks, blurred vision, nightmares and slurred speech. People with severe hypoglycemia may also experience seizures and loss of consciousness.

Prevention of Hypoglycemia

Untreated hypoglycemia may cause cardiovascular, kidney or bone problems. Furthermore, it may also cause nerve damage, infections, amputation or death. Hence, it is crucial to know the symptoms and preventive measures of hypoglycemia. If you are diabetic, you must monitor your blood sugar level frequently and keep a check on your daily diet. Never skip your meals and eat five to six small meals throughout the day to keep your blood sugar within normal range.

If there is an increase in your physical activities, consume additional calories during the day to maintain your energy. You can consult your healthcare provider to design a meal and physical activities plan so that the energy is balanced without causing low blood sugar. Glucose tablets can raise blood sugar levels. However, they should not be consumed without a doctor’s permission.


Once you understand the symptoms of high and low blood sugar, it is possible to avoid serious problems. Knowing the signs of hyperglycemia and hypoglycemia allows you to maintain a healthy lifestyle by incorporating the required preventive measures. Additionally, you can work with your healthcare provider to manage diabetes and other causes of low or high blood sugar.