Beth knew something was wrong when she began to feel weak, cold and clammy toward the end of her morning workout. Her mistake? She’d tried to fuel a long, hard workout on nothing but coffee and water. What’s more, she hadn’t eaten a bite since dinner the night before—nearly 12 hours ago. Now, low blood sugar was putting a sudden halt to her exercise routine.
Low blood sugar (also called hypoglycemia) occurs when the concentration of glucose in your blood drops below 70 milligrams per deciliter (mg/dL). Normal blood sugar levels range from about 60 to 140 mg/dL, depending on when you last ate.
If your blood sugar level drops, you may find you have difficulty concentrating, thinking clearly or expressing yourself. But not all people experience all or the same symptoms of hypoglycemia. Other signs include weakness, loss of coordination, drowsiness, hunger, dizziness, paleness or headache. Some people may experience sweating or a cold, clammy feeling; rapid heartbeat; trembling; irritability; and blurred or double vision.
People with diabetes experience low blood sugar from a number of conditions, including taking too much insulin, missing or delaying a meal, not eating enough food or drinking too much alcohol.
Those who don’t suffer from diabetes can experience hypoglycemia, too—most often when they skip a meal or have a long, strenuous exercise session. Some people wake up in the morning with low blood sugar (fasting hypoglycemia) while others have blood sugar dips two to five hours after a meal (reactive hypoglycemia). Certain medications can trigger low blood sugar, too, in which case your doctor may need to adjust or stop the dosage. Tumors, hormonal problems or other diseases also may be at fault.
Mild hypoglycemia may not be dangerous if quickly and appropriately treated. You can raise your blood glucose quickly with some form of sugar, such as a half-cup of fruit juice or soda or a handful of hard candies. See your doctor to determine if you have an underlying condition that should be treated. (Blood sugar levels below 50 mg/dL usually indicate disease.) Your doctor or a registered dietitian can suggest a meal plan to help you avoid low blood sugar.
Severe hypoglycemia can lead to seizures or unconsciousness—a potential tragedy if you’re driving a car or on a staircase—and in time can cause brain damage. People who’ve had diabetes for several years need to be especially cautious since they may become insensitive to hypoglycemic symptoms and can pass out without warning. Prevent such dire outcomes by working closely with your doctor to treat and prevent hypoglycemic episodes.