This content originally appeared on Everyday Health. Republished with permission.
By Stephanie Bucklin and Jessica Migala
Medically Reviewed by Kacy Church, MD
We all know how rotten dehydration feels. Not only do we feel sluggish and cranky when we don’t get enough water, but in this state the body isn’t able to pump enough blood to the heart, brain, kidneys, and muscles, says Robert Rizza, MD, an emeritus professor of medicine at Mayo Clinic College of Medicine and Science in Rochester, Minnesota. As a result, your organs don’t run well, Dr. Rizza says. There’s even some evidence associating mild to moderate dehydration with impaired blood vessel function and blood pressure regulation, even in healthy people, as described in one review.
Health Risks of Dehydration for People Managing Type 2 Diabetes
For people with type 2 diabetes, dehydration can be especially dangerous. That’s because dehydration causes blood pressure to fall and the body to secrete stress hormones like norepinephrine and epinephrine, which may raise blood sugar, Rizza explains. When you have high blood sugar, you will often need to go to the bathroom more, notes Mayo Clinic, contributing to further dehydration and a vicious cycle.
In one study, researchers looked at a small sample of men who took an oral glucose tolerance test in various hydration statuses. They found that for people with type 2 diabetes, going only three days with subpar water intake (17 to 34 ounces per day) impaired blood sugar response. The effect of dehydration was likely due to an increased level of the stress hormone cortisol, which prompts the release of glucose. People who consumed an amount in line with the recommendations for water intake — around 100 ounces — had better blood sugar control.
More research on the effects of chronic dehydration on these metabolic measures is needed. But people with diabetes are encouraged to consume the amounts set forth by the National Academy of Sciences, which is 91 ounces per day for women and 125 ounces per day for men, with some of that coming from water-rich foods like fruits and vegetables.
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Can Dehydration Affect Type 2 Diabetes Risk?
Although dehydration can lead to serious health issues, not much research has looked at whether chronic dehydration — and the associated higher blood sugar — may increase the risk of prediabetes and full-blown type 2 diabetes.
“There have been a variety of things dehydration has been suggested to contribute to, but not diabetes,” Rizza says.
But there may be a connection, says Anna Simos, MPH, a certified diabetes care and education specialist (CDCES) with the Stanford Health Care Diabetes Education and Prevention Program in Palo Alto, California. Indeed, according to a study that monitored healthy adults over nine years, people’s self-reported water intake was inversely associated with a risk of developing high blood sugar. This means that people who reported drinking less than half a liter of water per day were more at risk of elevated blood sugar than people who reported more than 1 liter.
Scientists theorize that dehydration can lead to an increase in the hormone vasopressin, which prompts the kidneys to retain water and the liver to produce blood sugar, potentially affecting the body’s ability to regulate insulin over time. (One paper, however, noted that there’s insufficient evidence linking various health conditions with dehydration, including type 2 diabetes. The one condition that has been shown to be caused by dehydration? Kidney stones.)
The bottom line: More research is needed to fully understand the relationship between dehydration and diabetes, but hydration likely “keeps blood glucose levels a little more stable,” Simos says.
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How to Stay Hydrated if You’re Managing Type 2 Diabetes
Even if scientists still have questions about exactly how dehydration affects people with type 2 diabetes, staying hydrated is clearly important for good health.
So how can you make sure you’re getting enough water to manage diabetes? Rizza and Simos offer the following tips.
Have some salt — but not too much. Too much salt can be bad for blood pressure, Rizza says, but you do need some to maintain proper hydration. When you eat salt, notes MedlinePlus, you help stabilize your electrolytes, which are charged substances that regulate essential functions in your body, helping you stay hydrated. If you already have high blood pressure, talk with your doctor about how much salt to consume.
Check your blood glucose levels in extreme heat, and drink water if they are elevated. When it’s hot, it’s easier to become dehydrated, according to Johns Hopkins Medicine. “Staying well hydrated can help reduce your blood glucose levels, which helps you manage the hormone insulin,” Simos explains. And make sure that your blood glucose test strips and insulin are stored in a cool, dry place, she says, so that they don’t lose their potency and accuracy.
Reach for hydrating snacks if you’re hungry. For example, choose a cold piece of melon or a few frozen grapes, Simos says. Drinking a glass of water isn’t the only way to get your fix.
Above all, pay attention to your thirst signals. Ultimately, ensuring you’re well hydrated will help you better manage type 2 diabetes, Simos says. “If you’re already dehydrated, you’re going to be prone to having high blood sugar because you don’t have as much fluid running around in your blood to hydrate and keep that equilibrium with glucose molecules,” Simos explains. She stresses this very fact to her own patients. “I want to keep them hydrated because it keeps their blood glucose levels a little more stable,” she says.
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Editorial Sources and Fact-Checking
Watso JC, Farquhar WB. Hydration Status and Cardiovascular Function. Nutrients. August 2019.
Diabetes Symptoms: When Diabetes Symptoms Are a Concern. Mayo Clinic. June 27, 2023.
Johnson EC, Bardis CN, Jansen LT, et al. Reduced Water Intake Deteriorates Glucose Regulation in Patients With Type 2 Diabetes. Nutrition Research. July 2017.
Report Sets Dietary Intake Levels for Water, Salt, and Potassium to Maintain Health and Reduce Chronic Disease Risk. National Academy of Sciences. February 11, 2004.
Roussel R, Fezeu L, Bouby N, et al. Low Water Intake and Risk for New-Onset Hyperglycemia. Diabetes Care. December 1, 2011.
Armstrong LE. Challenges of Linking Chronic Dehydration and Fluid Consumption to Health Outcomes. Nutrition Reviews. November 2012.
Fluid and Electrolyte Balance. MedlinePlus. June 20, 2016.
Dehydration and Heat Stroke. Johns Hopkins Medicine.