Blood Glucose and Dehydration

by Kelsey Bonilla Patient Expert

In the past, I assumed that the only association between diabetes and dehydration was that severe hyperglycemia (high blood glucose) would cause dehydration as one of the symptoms of diabetic ketoacidosis (DKA).

However, over the years I've noticed the occasional unexpected high blood sugar when I was mildly dehydrated due to exercise without consuming enough water.
I figured that was anecdotal and never gave it serious thought as a health issue worth pursuing.

When I did consider the possibility, it seemed logical to me that since diabetics are told to drink water to help bring down high blood glucose, perhaps the absence of hydration would cause blood sugar to rise. Maybe?

Last week summer came to San Diego in one hot wave
We moved to northeast San Diego in April, so this was our first experience of the inland heat in our non-air-conditioned house.

We've been sweaty and uncomfortable, especially while home most of the weekend.
During this stint, I noticed my blood sugars were running high despite healthy eating, normal insulin doses, and plenty of activity.
A nagging thought kept occurring to me, "Am I dehydrated?"

I tend to be better about drinking water when I'm at work during the week, sitting at my desk.
I certainly wasn't drinking enough to maintain hydration during this hot spell.

I got online and goggled, "dehydration and blood sugar" to see if I could locate information to confirm my suspicions.

Oh, wonderful internet!
I found dozens of articles and posts that explained that, in fact, dehydration can contribute to hyperglycemia.
It's actually pretty straightforward.
Basically, when we're dehydrated (even mildly) there is less liquid in our blood which means that the concentration of glucose (and other nutrients) is higher.

As the heat and humidity in Southern California has been relentless the past couple weeks, I'm now making a conscious effort to stay hydrated and have seen an improvement in my blood sugar control as a result.
Sometimes the simplest things can be easy to overlook!

Kelsey Bonilla
Meet Our Writer
Kelsey Bonilla

Kelsey wrote for HealthCentral as a patient expert for Diabetes.