Slight nitpick: at times, exercise can cause your muscles to directly take up glucose without the use of insulin. Yay exercise!
Ugh, not really. A lot of people (me included) think that Bernstein is one of the biggest quacks out there. I don’t want to hijack this thread, but did want to point out that it’s certainly not universally accepted that Bernstein is either non-fad or non-myth.
Close. *Intermediate *exercise will reduce your blood sugar. At the very onset of exercise, your blood sugar will go up when the liver dumps a bunch of glucose (from glucagon) into your bloodstream, but keep going and it will get into your cells (even for Type I diabetics). Keep going too long or too hard though, and the liver dumps out more glucose but your body can’t get it into your cells, and your blood sugar will be high again.
Exercise is important for diabetics, but it’s also tricky learning how to manage your glucose around it. Experience and a lot of test strips are key. 
Well on the show they said they put her through a test in a hospital where they wouldn’t give her any water at all while under observation to see what would happen. She kept having to urinate and got dehydrated pretty quick and the doc running the trial ended up having to give her an injection to replace her ADH to get her to stop urinating so much. (They also mentioned that they think what happened was head trauma damaged her pituitary gland so it didn’t produce ADH anymore.)
The best way to find out what works is just to test yourself. No one thing works all the time for everyone to bring down BG. Test yourself over and over. Yeah, you may have to go over the number of test strips that your insurance pays for and buy some yourself. This includes Bernstein’s method. It is extreme, but it works for plenty of people. (Even if you think his method is wisckery’ his site is a good source for detailed info on the chemistry and physiology of diabetes.)
The bottim line: Test yourself. That’s where the rubber meets the road.
When my late H was diagnosed in 1972 personal test kits were not available like they are now. Even in 1989, his home test kit took about 5 minutes to do and had you mixing solutions. Now it’s easy to find out what brings your BG down now, an hour from now, two hours from now, etc.
The question was mostly idle; I’m anal about managing my blood sugar. Getting introduced to diabetes by a 3-day hospital stay will do that.
I realize this is an old post, but as I’ve had quite a bit of experience with this topic lately I thought I’d post. They are all very correct in describing the correlation between dehydration and high BG. Being dehydrated will very much raise your numbers. While rehydration is key, drinking water at home isn’t going to really noticeably help your numbers. You still need to do all the things you normally do to address the increase such as take meds or insulin. However, should you be like me and find yourself at sky high numbers (as in the meter actually errors out because it’s too high!) you may find yourself in the ER and the very first thing they’re going to do is shove as much saline in you as possible until your numbers regulate. The amount of water you’re able to take in via an IV is much greater and processed more quickly than drinking can accomplish. I’ve seen my levels come down by 150 points in about an hour solely from IV hydration.
So yes, water does help, but not in a way that just increasing the amount you drink will improve high numbers. Your best bet is to stay hydrated in the first place as prevention. Like chronic pain, it’s easier to nip it in the bud early than to try to tackle it back down once it’s become a major problem.
Dakota923, thank you for that addition, (and welcome to The Straight Dope Message Board!).
The FIRST question any person with diabetes should ask their doctor, even before they get all that information about medication and diet and stuff: “When should I go to the ER?” There will be a low number and a high number. Share these numbers with your family. Write them down. (You’ll probably be unconscious or very woozy at the low number. So tell them now, before that ever happens.)
As a very generalized rule, anyone with a blood sugar under 40 or over 300 should seek medical attention, whether it’s from dehydration or something else. But I’ve had patients whose doctors have set different parameters for them, based on their health history, home environment, and proximity to a hospital.
I’ve got one dude, I’ve never measured under 400. And he’s totally asymptomatic at those numbers, because his body is so used to it. Of course, internal, invisible damage is still happening, so we’re working on it…but he starts to get woozy when his blood sugar hits 150 or less. (Or so he tells me.) His doctor has set a specific parameter for that guy, so I’m not calling him at every visit.
Am I correct that drinking water does not help my blood sugar go down?
Yes, in the most delightful way.
Well no, not really. But thanks to this zombie reawakening, I’ve got the song going through my head now…
In terms of lowering glucose levels via ‘hydration’, it is critical to note that what matters is not so much ‘hydration’ as it is ‘volume’ repletion, with ‘volume’ being essentially synonymous normal saline.
In other words, your blood volume will be increased by taking saline but won’t be touched by taking in pure water. It is restoration of the blood volume which lowers blood sugar in ‘dehydrated’ individuals. I put the term ‘dehydrated’ in scare quotes because most of the time people who are ‘dehydrated’ are lacking more than water. They are almost always also deficient in salt (sodium). Loss of both water and salt together leads to reduction in blood volume. As an aside, that is why giving ‘volume’ to people in shock (as saline, Ringers, blood, . . .) but not pure water, is therapeutic for them.
BTW, the reason that giving ‘volume’ back to diabetics who are ‘volume depleted’ will lower their sugar (but giving pure water won’t) is that the restoration of blood volume i) ‘opens’ up the kidneys allowing them to pee out the sugar and ii) restoration of blood volume turns off adrenalin and cortisol production both of which will be high in situations of volume depletion and both of which act to raise blood sugar (both are ‘stress hormones’ and are stimulated by low blood volume).
Finally, ‘dehydration’ is a horrible term which is almost never used correctly by doctors, med students, nurses, . . . I insist that on my teaching unit we talk about volume or tonicity (or both) but never ‘dehydration’.
I should probably have noted explicitly that water, in the absence of sodium to go with it, will not stay within the blood vessels. That is why giving water (say in the form of dextrose and water) is next to useless for shock (low BP). You must give saline (i.e, salt and water).
Without the salt (Na) to hold it in the blood vessels, ingested water will dissolve throughout the entire body water - a compartment 12X larger than that of the blood volume. So, for example, if 240 cc of water is administered/taken by someone, only 20 cc of it will wind up in the circulation.
Did anybody else see Skald’s name in the OP and think for a moment, “Oh, goodie, he changed his mind,” only to have your hope dashed when you noticed the date?
He’s still posting a little bit, with a speech to text thingy. 
So he did kinda change his mind, but his posting volume is down, probably because it’s a laborious process.
He ain’t dead yet! (Or he wasn’t on the 19th, when he last posted.)
(Seeing a zombified Askia thread is still a punch in the gut, though…)
Thank you, WhyNot, for that cheering news. I shall keep an eye out for Skald’s posts. I’m not familiar with Askia. Can you suggest a thread of hers*?
*I’m assuming Askia is (was?) female. As Jubal Harshaw once remarked, “Give her [a fictional character] a name that ends with an A. Suggests a c-cup.”
Askia was a young man who died in 2007. Askia was his actual name, as well as his username here.
This is probably my favorite OP of his. He was, actually, a lot like Skald: witty, shared with us the perspective of a Black man in America, and a heart way bigger than he wanted to admit.
WhyNot, thank you for introducing me to Askia. I can’t wait to read more of his posts.