Blood Sugar Spiking? You Might Be Dehydrated

Most people have about 60% water in their bodies. However, this amount can change depending on things like your age, gender and how much muscle or fat you have. From when you are a newborn to six months old, on average, your body is made up of 74% water.

No matter who you are, staying hydrated is very important for your body to fuction well. Hydration also plays a key role in diabetes management.

The dehydration problem

People with chronic illnesses like diabetes, renal disease or gastrointestinal disorders are more likely to become dehydrated. Dehydration can cause hospitalization and other health problems. 

Dehydration is responsible for about 1 to 3% of all hospital stays in the U.S. Where you live also matters. People who live in areas with extreme temperatures, limited access to clean water and high rates of infectious diseases that cause fluid loss are at a greater risk of dehydration.

Dehydration happens if you don’t drink enough water or if you lose water fast from sweating, vomiting or diarrhea. 

Symptoms of dehydration include:

• Headache, confusion.
• Tiredness (fatigue).
• Dizziness, weakness and lightheadedness.
• Dry mouth and/or a dry cough.
• High heart rate but low blood pressure.
• Loss of appetite but maybe craving sugar.
• Flushed (red) skin.
• Swollen feet.
• Muscle cramps.
• Heat intolerance or chills.
• Constipation.
• Dark-colored pee (urine). Your pee should be a pale, clear color.

Why does dehydration spike your blood sugar levels?

If you get dehydrated, it means there’s less water in your blood. This makes the sugar (glucose) in your blood more concentrated. Even if the amount of sugar in your blood hasn’t gone up, it can still cause high blood sugar levels because the balance of sugar and water has changed.

Think of it like this: when making maple syrup, you collect sap from trees. Sap is mostly water—about 95%—and only about 5% sugar. When you boil the sap to remove water, the sugar becomes more concentrated. This creates a thick, sweet syrup that tastes nice on pancakes. Less water means more sugar in the syrup.

Your blood needs enough water to keep the right balance of water and sugar.

Why is dehydration more dangerous for people with diabetes?

Dehydration with diabetes can be especially dangerous, particularly during hot weather, when you exercise hard or if you’re sick with diarrhea or if you’re vomiting. It can raise your blood sugar.

If you’re sick and can’t keep fluids down, go to the emergency room or urgent care. They can give you fluids through your vein (intravenous fluids) to help you rehydrate. It may feel unnecessary, but you don’t want to mess around with dehydration. Rehydrating with IV fluids, water or sport drinks can help lower your blood sugar to a safer level.

Be careful when choosing sports drinks like Gatorade, Powerade, Pedialyte, etc. to stay hydrated. They often contain a lot of sugar, so check the nutrition labels before buying. Ask your doctor whether you should take insulin when drinking them, or pick drinks with less or no sugar.

Severe dehydration can be life-threatening. This is because your blood becomes very concentrated with sugar, and you might have too few important minerals, such as sodium and potassium. Severe dehydration that’s left untreated can even lead to diabetic ketoacidosis (DKA).

Why is water important for diabetes management?

Drinking water is one of the easiest ways to support your overall blood sugar management, and there are a ton of benefits.

Water helps your body in loads of ways, including:

• Carrying oxygen and nutrients (including glucose) throughout your bloodstream to your cells
• Hormone production
• Neurotransmitter function
• Regulating your body temperature
• Keeping membranes moist
• Keeping your eyes clean and moist
• Smelling, tasting and swallowing food
• Bowel movements
• Passing toxins and waste through urine and sweat
• Metabolizing the food you eat for energy
• Dissolving minerals and vitamins in your food
• Producing saliva
• Lubricating your joints
• Insulating your brain, spinal cord, organs and fetus (during pregnancy)
• Protecting your joints/organs/bones through shock absorption

Can you drink too much water?

Water intoxication is rare, but it can happen. It occurs when someone drinks too much water. If you think you are over-hydrated, talk to your doctor.

You may need to limit your water intake if you:

• Have certain health conditions, including kidney, liver or heart failure
• Experience symptoms of over-hydration
• Take medications that cause water retention
• Take other medications, including some antidepressants and opiates
• Have a doctor who has instructed you to reduce water intake for any reason

Mild symptoms of water intoxication include:

• Nausea
• Vomiting
• Bloating

Severe symptoms of water intoxication include:

• Seizure
• Confusion
• Coma

Water intoxication can be life-threatening. If your symptoms are severe, go to urgent care or the emergency room. They may need to replace the excess water with sodium. Do not try to treat this yourself at home.

Build a new habit: drink enough water daily

If you’re not used to drinking enough water, start small and work your way up. Building new habits takes time and this one is worth it. A good rule of thumb is to drink half of your body weight in ounces of water per day. This means if you weigh 180 pounds,  you should drink 90 ounces of water per day. 

Exact calculations vary by person. If you’re at risk for dehydration on top of your usual intake, you’ll need to step it up. For example, if you’re working out a lot, are exposed to higher temperatures or have a higher muscle mass.

You may need to up your usual water intake if you are:

• Taking a medication that increases your body’s urine output
• Exercising intensely, especially for those involved in endurance training
• In extremely hot weather
• Experiencing diarrhea or vomiting and need to replenish
• Pregnant or breastfeeding

Always talk to your doctor about your water goals and worries.

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