Down But Not Out

Low blood sugar is a major bummer, and it's dangerous too. Here's what scientists are learning about how it works.

When Hypoglycemia Happens Low blood sugar usually occurs for one of three reasons in kids with juvenile diabetes:

1. They take too much insulin for the amount of food they eat or the amount they have exercised.
2. They don't eat enough food or don't eat on time.
3. They exercise too much for the amount of insulin they take.

Hypoglycemia often strikes just before meals, when blood sugar tends to be low anyway. It can also occur while exercising or afterward, and it's becoming more common during sleep, especially in kids.

When blood sugar dips in a person who doesn't have diabetes, the pancreas produces a chemical called

glucagon. The glucagon enters the bloodstream and travels to the liver. There, it causes the liver to release another chemical, glycogen, into the bloodstream.

Glycogen, which is a form of glucose (sugar), raises the blood sugar level.

In a person with juvenile diabetes, though, the pancreas can't make glucagon. So a hormone called epinephrine kicks in. Epinephrine is produced by a small gland that sits on top of each kidney.

When your blood sugar drops, the gland releases epinephrine, which travels to your liver. The liver then

breaks glycogen down into glucose, which raises your blood sugar. Epinephrine doesn't work as well as glucagon to raise blood sugar, but sometimes it's enough to prevent your blood sugar from dropping further.

If your blood sugar keeps dropping, you may become confused, have a seizure or even lose consciousness, a serious condition called hypoglycemic coma. Taking glucose tablets, glucagon or a food that contains glucose as soon as you "get the shakes" can quickly boost the amount of glucose in the bloodstream and prevent hypoglycemic coma.

Why You Should Pay Attention Preventing hypoglycemia is important, say experts, because a bout of low blood sugar today increases your chance of having low blood sugar again tomorrow.

That's because low blood sugar weakens the effect of epinephrine. The body then can't respond to

hypoglycemia as well as it should. And that spells trouble during sleep.

Robert Sherwin, a diabetes expert at Yale University in New Haven, Connecticut, says low blood sugar during sleep is becoming more and more common, especially among kids. Kids who become hypoglycemic during deep sleep don't sense that their blood sugar is low. So the blood sugar can keep falling and the kids won't have any idea that they should wake up and take a few glucose tablets.

That's why, says Dr. Sherwin, kids should be especially careful about controlling their blood sugar all day long.

Brain Matters Hypoglycemia also affects how well a person can think. You know what it's like when those shakes come!

Dorothy Becker, a diabetes expert in Pittsburgh, is trying to find a way to block hypoglycemia and help the brain deal with it better.

Normally when the blood sugar drops, the body makes a chemical called lactate. The body of a person with juvenile diabetes, though, can't make lactate.

Dr. Becker thinks lactate pills might prevent some of the effects of hypoglycemia on a person's ability to think

clearly. And that might help you get through an exam if your blood sugar dips in the middle of it.

Wouldn't that be great! Just as great as it will be when these researchers learn how to stop low blood sugar once and for all.