Last updated: Apr 21, 2008
You'll need to test your blood sugar if you think you have hypoglycemia.
Although type 2 diabetes is characterized by blood sugar that is too high, some people take insulin and others medications (such as sulfonylureas) that can occasionally drive blood sugar too low.

When blood sugar is too low—generally less than 70 mg/dL—it's called hypoglycemia, and it can become a medical emergency. (The normal range for fasting blood sugar is 70 to 99 mg/dL, though it varies somewhat with age, and is lower during pregnancy and in children.)

You can lose consciousness
Hypoglycemia is more likely to occur when you start taking a new medication (it can take practice to match your food intake to your insulin dose, for example) or if you exercise more than usual.

As blood sugar drops to low levels, you may feel:

• Shaky
• Irritable
• Sweaty

This can occur within 10 to 15 minutes, and in extreme cases you can even lose consciousness and experience seizures if you don't consume some glucose (though hypoglycemia is usually mild in people with type 2 diabetes, and readily fixed by drinking juice or eating other sugar-containing items, such as glucose tablets or four to six pieces of hard candy).

You'll need to test your blood sugar to confirm that you're having hypoglycemia—some people become irritable if blood sugar is too high, so it's not always obvious.

If you drink sugar-containing juice, or some other form of carbohydrate, it should bring blood sugar back into the normal range. You can also purchase glucose pills or gels in the pharmacy that can get blood sugar back on track.

“You should always have a glucose source in the car,” says Yvonne Thigpen, RD, diabetes program coordinator at Mount Clemens Regional Medical Center in Mt. Clemens, Mich. You never know when youll hit construction or get stuck in traffic, she says.

Hypoglycemia can occur at night
Dick Robbins, 72, of Hot Springs Village, Ark., was diagnosed with type 2 diabetes in 2001, and is now taking metformin (an oral medication that doesn't typically cause hypoglycemia), as well as a short-acting insulin, Novolog (insulin aspart), and a long-acting insulin, Lantus (insulin glargine). In that time hes had six or seven episodes of hypoglycemia.

“It usually occurs between midnight and 1 a.m. and I always wake up soaking wet—but only from the waist up. My head, shoulders, and upper back are just dripping with sweat,” he says.

He checks his blood sugar, and if its low, he goes straight to the refrigerator and drinks some pineapple juice and eats a peanut butter sandwich. He waits 45 minutes or so, and then checks his blood sugar again. If its in the normal range, he heads back to bed.

You can have hypoglycemia without knowing it
Some patients with diabetic nerve damage, known as neuropathy, may not experience any of the symptoms of hypoglycemia, even when their blood sugar is very low.

In that case, you may need to test your blood more often and rely on family and friends to help you notice if blood sugar starts to drop.

“My mom is one of them,” says Thigpen. “Her blood sugar can go down to 30 mg/dl and all she says is shes kind of tired.” In those cases, family members can help determine if blood sugar is heading into the danger zone.

“You want to offer them a source of quick-acting carbohydrates,” says Thigpen. “The gold standard of that treatment would be 15 grams of glucose,” she says, which can be purchased over-the-counter in pill or gel form at the pharmacy.