Why Does Diabetes Cause Fatigue?

You were diagnosed with Type 2 diabetes recently and find yourself with so many questions. One that’s on your mind often: “Why am I so tired?”

If you find yourself frequently feeling fatigued, you aren’t alone. Fatigue is so common among those who have diabetes that there’s a name for it — diabetes fatigue syndrome.

It’s important to make a distinction between fatigue and tiredness. Someone who is simply tired will usually feel rejuvenated after a period of rest, while someone experiencing fatigue may still feel lethargic.

“It is very common to see patients with diabetes having fatigue as one of their more bothersome symptoms,” says Dr. Maria Escobar Vasco, an endocrinologist with University Health. “We typically see it more often among patients who have been recently diagnosed or who have uncontrolled diabetes.”

There’s good news, though. While it’s common to experience fatigue at times when you’re managing diabetes, you can take steps to fix the underlying causes and feel more energy. 

Possible Diabetes-Related Causes of Fatigue

There are many different potential reasons for fatigue among those who have diabetes. Perhaps most importantly, blood sugar itself can be a contributing factor. Those who have very high levels of glucose often experience fatigue, but fatigue is also fairly common among those who have very low levels of glucose.

Other causes of diabetes-related fatigue can include:

  • An inactive lifestyle. While it might seem like it would be the opposite, being physically inactive can contribute to fatigue.
  • Chronic pain. Diabetic neuropathy, a type of nerve damage that causes pain and tingling, can contribute to fatigue in multiple ways. It can make it more difficult to get meaningful sleep and rest, and medications used to treat neuropathy often cause somnolence, a type of drowsiness that may feel like fatigue.
  • Dehydration. When the amount of water the body is excreting is more than you’re taking in through your diet, dehydration results. Dehydration can cause high blood sugar because the amount of water in the blood decreases, increasing the concentration of glucose. High blood sugar, in turn, causes fatigue.
  • Diabetic heart disease. Many people who have diabetes also have heart disease. Strain on the heart can cause fatigue, particularly after exercise or other exertion.
  • Mental health issues. Those who have diabetes are at a higher risk of developing certain mental health conditions, including anxiety and depression. When untreated, these conditions can worsen fatigue.
  • Sleep problems. Having insomnia or other sleep disorders, including sleep apnea, can contribute to fatigue, as can simply not sleeping well on a regular basis or not getting restful sleep.

These potential causes for fatigue can be related to certain medications used to treat diabetes, since they often cause symptoms like increased urination or nausea.

How to Manage Diabetes Fatigue

If you’ve been diagnosed with diabetes and are experiencing fatigue, your first step is to check in with your care team.

“Talk with a primary care doctor about your symptoms,” Escobar Vasco says.  

“There may be associated conditions that have not been diagnosed and need further workup, like depression, sleep apnea, heart or lung conditions, or vitamin deficiencies, or you may need changes to medications.”

If an underlying cause isn’t to blame for your fatigue, try adjusting your habits to see if lifestyle changes will help. The most important thing you can do is to work with your providers to get your blood sugar level under control.

You can do this by:

  • Taking medications as prescribed
  • Eating a nutrient-filled diet that minimizes high-carb and high-sugar foods
  • Staying well-hydrated
  • Managing stress
  • Making physical activity a part of your daily routine 

Losing even a small amount of weight can also be helpful in lowering blood sugar into a healthy range.

“Patients should really come to their doctors and discuss fatigue, which is common,” Escobar Vasco says. “There may be lots of different things you can do to feel better.”

Diabetes Care at University Health

Learn about the world-class diabetes care for adults and children at University Health.

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