Free shipping & prescription with all orders
ENDS IN 00:00:00:00
Free shipping & prescription with all orders
ENDS IN 00:00:00:00
Use your HSA/FSA for any Nutrisense program
ENDS IN 00:00:00:00
Use your HSA/FSA for any Nutrisense program
ENDS IN 00:00:00:00
Promo code SPRING2022 will be automatically applied at checkout!

Dehydration and Blood Sugar: What You Need to Know to Stay Healthy

Monica McCafferty, MS, CNS

Published in Glucose

8 min read

June 30, 2022
December 19, 2023
a person holding a glass of water
a person holding a glass of water

Staying hydrated is vital for many of our bodily processes. Water makes up about 55 to 60 percent of the human body, meaning that when you lose even a few pounds of water weight, it can take a significant toll on your health.

Let’s look at just how vital water is for overall health and how dehydration, among other things, can affect blood sugar levels.

The Importance of Water for Optimal Health

girl drinking water

All human beings require a certain amount of water for survival. But why is it so essential? Well, for one, it helps carry nutrients and oxygen to cells in the body and supports brain, heart, kidney, liver, skin, and skin health. Staying hydrated can also help keep you satiated and can lower the risk for obesity in adults.

When you don’t drink enough water, you may see impacts on some aspects of cognitive function like vigor, memory, and your ability to pay attention. One study even found evidence suggesting that staying hydrated throughout life can lower your risk of heart failure

Looking for tips and tricks to help you stay adequately hydrated? Read what our dietitians recommend here

How Much Water Should You Drink in a Day

You may have heard the “drink eight cups of water per day rule” as a child. While this is an excellent place to start, many different factors can influence your recommended daily fluid intake.

According to the Mayo Clinic, adult men should generally aim to consume 3.7 liters of fluids (15.5 cups) per day. In comparison, adult women should aim for 2.7 liters (or 11.5 cups). Remember that these recommendations include water and fluids from water-dense foods and other beverages you drink throughout the day. 

Other factors influence how much fluid you need to drink. These include:

  • Exercise Levels
  • Hot or Humid Weather
  • Being Pregnant  

Everyone is unique, and your hydration needs may differ from others, so it’s essential to learn what’s right for you.

Warning Signs of Dehydration

woman laying down outside

Dehydration can harm your health, which is why it's vital to be aware of its symptoms and warning signs.

Here are a few symptoms that can indicate dehydration:

  • Confusion
  • Excessive thirst
  • Dark yellow urine
  • Fatigue
  • Dry mouth
  • Feeling dizzy

Does Dehydration Cause High Blood Sugar Levels?

In addition to its effects on the brain, heart health, and kidney function, dehydration can also be associated with high blood sugar levels.

A study conducted on a group of healthy individuals found that low water intake was associated with the development of hyperglycemia and risk of diabetes over time. This can occur because the body needs sufficient water to transport glucose throughout the bloodstream. A lack of adequate fluids can cause blood sugar to become too concentrated.

For people with type 2 diabetes, staying hydrated is especially important as this condition can lead to excessive urination. In this case, the body passes water rather than using it to support blood circulation, which can cause dehydration and result in higher blood glucose levels.

7 Common Factors that Can Cause a Blood Sugar Spike  

Besides drinking plenty of water, many factors can lead to abnormal blood sugar levels. Being aware of these factors is vital whether or not you have diabetes, and taking steps to limit these situations can help support normal glucose levels.

Here are seven common things that might be negatively affecting your glucose levels.

Excess Carbohydrate Intake

Your body converts carbohydrates to glucose after digestion. They're then transported to be used as fuel. Although carbohydrates are a great energy source, eating too many carbohydrate-containing foods can lead to spikes in glucose. 

Reducing your intake of simple carbs such as sugary drinks, table sugar, candy, and refined or processed carbs (found in things like white pasta and white bread) can help limit blood sugar spikes.

To manage your glucose levels while enjoying your favorite foods, choose high fiber complex carbohydrates like whole grains and sweet potatoes with a source of protein.

This combo can help the body digest carbs slower and prevent large amounts of glucose from flooding into the blood all at once.


Stress levels in the body can significantly impact your blood glucose levels when stress hormones such as cortisol are released. These hormones can cause high blood pressure, insulin resistance, and higher blood sugar levels.

Stress hormones can also affect insulin sensitivity, so it’s crucial to find ways to manage stress and avoid the harmful side effects of chronic stress.

Eating Late at Night 

a person eating

Another factor that can lead to negative glucose trends is eating late at night or before sleep. It's because when we eat at late hours, the body’s circadian rhythm can become disrupted, causing issues during sleep. This is especially true when eating carbohydrates or sweet foods. 

Late-night snacking has also been linked to increased obesity and type 2 diabetes risk. So it’s best to try to limit snacking before bed for better sleep and improved blood sugar trends.

Not Enough Sleep

Adequate sleep is important for overall health and wellbeing, and a lack of sleep can even lead to deeper health conditions such as obesity. 

When you don’t get enough sleep or when sleep is disrupted during the night, you are more likely to experience spikes in your blood sugar. The same is true the other way around, as having irregular blood sugar levels can disrupt your sleep, leading to a vicious cycle.

A lack of sleep may also affect insulin levels, which will lead to negative trends for your glucose levels.

Breaking Your Fast With Carbohydrates

a plate of cinnamon rolls

Whether you practice intermittent fasting or are just eating your morning meal, it’s a good idea to consider what foods are blood-sugar-friendly options for breaking your fast.

Studies show that breaking a fast without carbohydrates can benefit glucose response, as glucose levels are more likely to spike levels after a long period without eating. 

To enjoy your favorite carbohydrates after a fast, opt for complex carbs like whole grains and pair them with a source of high-quality protein to help slow the digestion process.

Not Enough Protein

Protein is a vital macronutrient and part of a healthy, balanced diet. Consuming adequate levels of high-quality protein helps keep blood sugar levels regulated. It can also help blunt potential glucose spikes when eating high-carbohydrate foods.

Protein can help keep you full for longer, promote muscle growth, and support bone health.

Low Activity Levels

someone using their phone from bed

Exercise is extremely important for healthy blood glucose levels. Some studies have shown that regular exercise can increase muscle glucose uptake in the body, which leads to fewer glucose spikes. Staying active is also great for your body’s mitochondria, which helps to convert glucose into energy more efficiently.

Getting plenty of exercise is beneficial for people with obesity. It may even help reverse prediabetes! So there are many critical benefits to support staying as physically active as possible.

5 Uncommon Factors that Can Cause a Blood Sugar Spike

Now that we’ve covered the common factors impacting blood sugar, let’s look at a few uncommon things that can lead to unforeseen spikes.

1) Too Many Cups of Coffee

a cup of coffee

Drinking coffee in and of itself doesn’t necessarily lead to glucose spikes. In some instances, it can support healthy blood sugar levels

But drinking coffee (or consuming more than 200 milligrams of caffeine daily) may lead to unfavorable glucose levels in individuals with type 2 diabetes.

If you prefer to add sugar to your morning cup of coffee, it’s essential to watch your portions. A few teaspoons of sugar can add up quickly and lead to energy crashes later in the day.

2) Sunburn

You may be surprised to learn that sunburns can affect your blood sugar. In addition to potential risks for skin cancer and other conditions, sunburns can cause stress levels to be elevated while your body works to heal itself.

Spending lots of time in the sun can affect more than just your skin, it may also cause your glucose levels to fluctuate since your body has to work harder to cool off. Heat and humidity can also affect the way your body uses insulin, so it’s important to take breaks and drink plenty of water if you’re spending extra time outdoors.

Stress also triggers high blood sugar levels, so avoiding anything that can lead to elevated stress levels, including sunburn, is vital for overall health.

3) You Skipped Out on Breakfast

a bowl of nuts and oranges

Skipping breakfast may work for some, and the idea that it's outright bad for your health is a myth! But it can affect different people differently. It has also been linked to elevated glucose levels in healthy individuals. 

It happens because increased meal frequency can improve glycemic response throughout the day, especially for individuals with diabetes.

Another study on people with type 2 diabetes demonstrated that not eating breakfast led to increased glycemic variability and may negatively impact the body’s circadian rhythm. 

4) Time of Day Affects Blood Sugar Levels

Time of day can have a surprising impact on glucose levels. It's because the body’s circadian rhythm can affect glucose metabolism

Blood sugar levels can often be higher in the morning for those with diabetes, likely because of lower insulin levels and the release of hormones. 

It’s essential to work with a doctor or medical professional if you are someone who experiences abnormal blood sugar levels during the night and early morning. It will help you determine what factors may be contributing to these fluctuations.

5) Your Nose Spray has Chemicals That Triggers a Spike

a man using nose spray

Some decongestants may contain oxymetazoline, which has been observed to cause slight spikes in blood glucose levels. 

If you're someone with diabetes, it’s important to understand the potential side effects of your medications and consult with your doctor to find out what medications are right for you.

Related Article

Read More

Engage with Your Blood Glucose Levels with Nutrisense

Your blood sugar levels can significantly impact how your body feels and functions. That’s why stable blood glucose levels can be an important factor in supporting overall wellbeing.

With Nutrisense, you’ll be able to track your blood glucose levels over time using a CGM, so you can make lifestyle choices that support healthy living.

When you join the Nutrisense CGM program, our team of credentialed dietitians and nutritionists are available for additional support and guidance to help you reach your goals.

Ready to take the first step? Start with our quiz to see how Nutrisense can support your health.

Find the right Nutrisense program    to help you discover and reach your health potential.
Natalie Carroll, MS, RDN, CDN, CLC

Reviewed by: Natalie Carroll, MS, RDN, CDN, CLC

Natalie received her degree in Dietetics from Mansfield University and a Master’s in Clinical Nutrition from the University at Buffalo. Her career has included nutrition education and program development in her local community, adjunct faculty at several collegiate institutions, and clinical nutrition in both inpatient and outpatient settings.

Recommended Articles