Does drinking water lower blood glucose?

So does drinking water lower blood glucose? If you’re dehydrated, yes. In this case it will increase your glomerular filtration rate and give the excess sugar somewhere to go. Some people recommend that you drink lots of water after eating a high carbohydrate meal and spiking your blood sugar though. While it’s not going to hurt you, it’s probably not going to do much either. Trust me, I’ve tried it after a curry and naan bread and it didn’t work.

Water is a magic potion, especially after we started pouring it into bottles and selling it. I remember a time before everyone was running around with a water bottle, worried sick about whether they were drinking enough. These days people actually die from overhydration as well as dehydration. The phenomenon is known as water intoxication, where excess water dilutes sodium levels. This causes fluids to move into your cells which then swell up. The result is a potentially fatal brain edema.

According to Google a total of 14 people have died from too much water. This includes a teen who drank four gallons during football practice, and a woman who had two gallons as part of a radio station contest. You can kill yourself on pretty much anything, providing the dose is right.

Thirst is strictly regulated in the hypothalamus, so drinking when you’re thirsty is the way to go. The chance you’ll die from dehydration is almost nonexistent. Unless of course you’re running a marathon, or suffering from a dehydration illness. Dehydration is especially dangerous for diabetics, because of the vicious cycle involved.

When the body loses water from vomiting or diarrhea the glucose gets left behind. This causes blood glucose to rise. At the same time less supply goes to the narrow vessels in the peripheral tissues, so blood glucose continues to climb. High blood glucose will make you urinate more which drives it up even further. When blood glucose is elevated there’s an added bonus: you become more insulin resistant.

I noticed this a few weeks back, when I was sick with fever and vomiting. For three days I woke up to crazy numbers between 11-14 mmol/l (198-252 mg/dl) , and injected insulin like it was water. You’re supposed to increase your basal insulin on sick days, but I haven’t quite worked out how to do this. Instead I’m stuck performing damage control and incessantly jabbing myself with NovoRapid.

As a general rule I’ve found that if I go into the double digits, I need twice the amount of insulin to drop me down as much as I would normally. You want to avoid double digits like the plague, but when you’re sick it’s hard not to hit them. The real danger when you’re ill is diabetic ketoacidosis. It’s a life-threatening condition that develops from high blood sugar and dehydration. Because of all these things drinking lots of water is important to a sick diabetic, when blood sugars run high. It’s not the solution to your post-meal spikes though.