Dehydration can cause a person’s blood sugar levels to rise. This occurs when water in their bloodstream decreases. As such, this results in a higher concentration of glucose being present in the blood.
Dehydration can occur if more water and fluids leave a person’s body than enter it. Dehydration can cause a number of symptoms,
- feeling thirsty
- dry skin and lips
- fatigue
- dark urine and decreased urine output
- headaches and lightheadedness
- dizziness and fainting
In addition, dehydration can cause blood sugar levels to rise, as less water in the body means a higher concentration of blood sugar.
In this article, we will discuss how dehydration can affect blood sugar levels.

Dehydration occurs when the water losses from the body
Common causes of dehydration can include:
- Excessive water loss from the skin: This can include water loss due to:
- heat
- exercise
- burns
- severe skin disease
- Failure to replace water loss: This can be due to immobility or an impaired thirst mechanism.
- Excess water loss from the kidneys: This may occur due to:
- medications, such as diuretics
- acute and chronic kidney disease
- post-obstructive diuresis, which involves excessive salt and water loss
- Excess water loss from the gastrointestinal tract: This may occur due to:
- Other medical conditions: Other medical conditions that cause water loss in the body include:
- pancreatitis
- peritonitis, a disorder in an area of tissue around the inside of the stomach wall
- sepsis
- severe hyperthyroidism, when the thyroid gland produces too much hormone
- asthma
- chronic obstructive pulmonary disease
As such, it is particularly important for a person with diabetes to monitor their blood sugars when they are ill, exercising, and in warmer climates. Over time, high blood sugar levels
Hyperglycemia is the medical term for
When a person has dehydration, the amount of water in their bloodstream decreases. This causes a person’s blood to contain a
This does not mean there is more blood sugar in the bloodstream. It means that the ratio of blood sugar to water has increased, causing the former to rise. Dehydration can cause both mild and significant spikes in blood sugar levels. If it causes a more significant increase, it may lead to hyperglycemia.
Hyperglycemia may also affect the hydration of someone with type 1 diabetes. A
Symptoms of dehydration
- feeling thirsty
- dry skin and lips
- fatigue
- dark urine
- decreased urine output
- headaches
- muscle cramps
- lightheadedness
- dizziness
- fainting
Significant dehydration can cause a person to experience low blood pressure, or hypotension.
Symptoms of hyperglycemia
- feeling thirsty
- feeling tired or weak
- headaches
- increased urination
- blurred vision
If a person has hyperglycemia for a long time and does not treat it, they may develop diabetic ketoacidosis (DKA). This term refers to a potentially life threatening complication, where the body begins to break down fats too quickly. While DKA can occur in people with type 2 diabetes, it is more common in those with type 1 diabetes.
DKA occurs when the body does not produce enough of the hormone insulin or if cells stop responding to it. Without insulin, the body cannot use blood sugar for fuel. This means it instead breaks down fat into acids called ketones for energy. However, this causes the blood to become acidic.
If a person shows the following symptoms of DKA, they should seek immediate medical care:
- shortness of breath
- fruity smelling breath
- nausea and vomiting
- a very dry mouth
A person can follow
- eating a nutritious diet containing plenty of fruit and vegetables
- maintaining a moderate weight
- getting regular physical exercise
- drinking enough water
- monitoring blood sugar levels to see what causes them to go up or down
- eating meals at regular times and not skipping meals
- eating foods that are lower in:
- calories
- saturated fat
- trans fat
- sugar
- salt
- drinking water instead of fruit juice or soda
- limiting alcoholic drinks
- controlling food portions
Dehydration occurs when the water losses from the body are greater than the water someone takes in from drinking. It can cause a person’s blood sugar levels to rise. This occurs when the amount of water in the bloodstream decreases, increasing the concentration of blood sugar in the blood.
Symptoms of dehydration include feeling thirsty, dry skin and lips, fatigue, and dark urine. Hyperglycemia is the medical term for high blood sugar levels. Symptoms of hyperglycemia include feeling thirsty, feeling tired or weak, headaches, increased urination, and blurred vision.