Everyone knows that dehydration means not having enough water in the body, but perhaps not everyone realizes that being diabetic increases both the risk of dehydration and the possibility of serious complications. In this article, we take a deep dive into the issues around dehydration and diabetes, explaining why diabetics are particularly at risk of becoming dehydrated and how this potentially life-threatening situation can be avoided. First, though, let’s start by looking in more detail at dehydration before turning to how it links to diabetes.

What is dehydration?

The human body is mostly made up of water, with the liquid accounting for 50–60% of body weight. In order for the body to function properly, it’s essential to maintain that level of water. For example, without the right hydration, the human body struggles to maintain the correct temperature, produce hormones, carry nutrients through the bloodstream, metabolize food, and dispose of toxins.

If the body’s water weight level falls below 50%, the outcome is dehydration, which has consequences that can range from mild to deadly. Although simply drinking enough water is enough to prevent dehydration, the condition is still surprisingly common. Indeed, one study found that 75% of Americans regularly suffer from dehydration.

What are the links between diabetes and dehydration?

Diabetic people are particularly at risk of becoming dehydrated because having a high blood sugar level is one of the factors that causes the body to be less hydrated. That is because when the body experiences high blood glucose levels the kidneys attempt to remove some of the excess glucose which then passes out of the body as urine.

All the extra water lost through that additional urination increases the risk of dehydration. The cycle of excessive urination continues so long as the body’s blood sugar level is high. As the water goes out, the concentration of sugar in the blood increases further, creating a vicious circle of higher blood sugar levels and less hydration, both of which feed off each other.

People with type 2 diabetes are particularly at risk of blood sugar spikes when they are dehydrated. The reason for that is that dehydration also makes blood pressure fall, which causes the body to release more of the stress hormones cortisol, epinephrine, and norepinephrine. The release of those stress hormones leads to the production of more glucose and, consequently, higher blood sugar levels.

It’s important to note that even diabetes insipidus, a form of the condition that is not associated with high blood sugar levels, can increase a person’s risk of dehydration. That is because the symptoms of diabetes insipidus include frequent urination.

To date, however, research has not found a link that suggests that dehydration causes diabetes. The link is the other way around – diabetes can contribute to dehydration, with potentially serious consequences. In order to prevent those consequences, it’s necessary to look at and understand the symptoms of dehydration, which are listed below.

The symptoms of dehydration

The initial symptoms of dehydration to look out for are as follows:

  • Feeling thirsty
  • Having a dry mouth and dry eyes
  • Having a headache
  • Feeling tired
  • Having dizzy spells
  • Urine that is dark yellow

If you or anyone in your care experiences any of these symptoms make sure to rehydrate at the earliest opportunity. If the person in question is diabetic, it is even more important to make sure they get properly rehydrated as soon as possible. Consultation with a healthcare professional can also help to identify ways to prevent dehydration.

The symptoms of extreme dehydration are as follows:

  • Feeling lethargic
  • Experiencing low blood pressure
  • Sunken eyes
  • Pulse becomes weak and/or heartbeat becomes rapid
  • Feeling confused

If you or anyone in your care experiences these serious symptoms of dehydration then as well as trying to rehydrate as quickly as possible you should also treat the situation as a medical emergency and seek whatever help is necessary.

The consequences of dehydration for diabetic people

The potential consequences of dehydration for diabetic people include the following:

  • Kidney failure: The kidneys can only work properly if there is enough fluid in the body. Without it, they can fail, especially in cases where the dehydrated person already has some problems with their kidneys. As diabetic people are particularly prone to chronic kidney disease, they have to be especially mindful of the risk of further kidney damage due to dehydration.
  • Ketoacidosis: Dehydration can indicate that a diabetic person is experiencing extremely high blood sugar levels. For diabetics, such a rise in blood sugar levels can cause ketoacidosis, i.e., a very high level of ketones in the body. Ketoacidosis is a complication that is more common in people with type 1 diabetes. Its symptoms include a flushed face, dry skin, headaches, vomiting, and stiffness of the muscles. In severe cases, the condition can lead to a diabetic coma.
  • Hyperosmolar hyperglycemic nonketotic syndrome (HHNS): This life-threatening condition can occur in people with non-insulin-dependent diabetes as a result of dehydration.

How can dehydration be prevented and treated?

The obvious way to prevent or treat dehydration is to have a drink. However, it’s important to note that not all drinks are good for dealing with dehydration, some can even make it worse.

When it comes to dehydration, the best solution is the simplest: drink water. Some recommendations state that women with diabetes should aim to drink around 1.6 liters per day; that figure rises to 2 liters for diabetic men. However, those figures have to be adjusted based on individual needs and circumstances.

For example, you should consume more water when exercising in hot weather or taking medications that may cause thirst as a side effect. On the other hand, you should consume less water if you are taking medications that cause water retention.

It’s also important to note that drinking sugary drinks, like sodas, fruit juices, or energy drinks, can lead to more severe dehydration as they can spike blood sugar levels. Other drinks to avoid include anything containing caffeine or alcohol.

Other ways in which diabetic people can prevent dehydration include the following:

  • Avoiding heat exhaustion: Diabetic people are particularly prone to overheating so should be especially mindful to avoid strenuous exercise or too much sun exposure on hot days. The signs of heat exhaustion to watch out for include excessive sweating, dizziness, fainting, headaches, nausea, increased heartbeat, and muscle cramps.
  • Regular monitoring of blood sugar levels: Exposure to heat can cause glucose levels to fluctuate, meaning it is even more important to check your blood sugar during hotter times when the likelihood of dehydration is also higher.
  • Storing insulin in a cool place: To be effective, insulin should not be stored in any extreme temperatures.

In cases of severe dehydration, it might also be essential to replace lost electrolytes in the body. That can be achieved by drinking a solution containing electrolytes or a drink that is naturally high in electrolytes such as coconut water. Electrolytes can also be found in a wide range of healthy foods and drinks.

The importance of getting medical advice when managing dehydration

It’s also crucial to stress the importance of seeking medical advice when required to help manage dehydration. That is particularly the case for diabetics who need to be especially careful when treating dehydration to avoid causing extra blood sugar spikes. Anyone who self-adjusts their insulin should consult their medical team before making any changes to the amount in response to dehydration.

Healthcare professionals might advise people with diabetes insipidus to drink a certain amount of water each day and also instruct them to take in extra electrolytes if they become dehydrated. In cases of hyperosmolar hyperglycemic nonketotic syndrome, treatment with hypotonic fluids is required to address the situation.


Diabetes and dehydration go hand in hand since high blood sugar levels can contribute to the body losing extra fluid and becoming dehydrated. Even the form of diabetes that is not associated with high blood sugar levels, diabetes insipidus, can still cause dehydration because one of its symptoms is excessive urination.

Not only can diabetes cause dehydration but also the potential impact of dehydration on diabetic people can be worse.  This impact includes such serious, and potentially life-threatening conditions as kidney failure, diabetic ketoacidosis, and hyperosmolar hyperglycemic nonketotic syndrome.

Diabetic people must take extra care to prevent dehydration by drinking lots of water or other suitable fluids. Drinks with high sugar content, alcohol, or caffeine should be avoided because they can make dehydration more likely. In some cases, drinks or food containing electrolytes will be required to replace those that the body has lost during dehydration.

In cases of severe dehydration, it is essential to manage the situation as an emergency, providing immediate rehydration and medical attention as soon as possible.