If it's been a while since you ate and you experience weakness, dizziness or sweating and shaking all of a sudden, it might be due to hypoglycemia — commonly called low blood sugar. Though this can be frightening or even dangerous, hypoglycemia is preventable and easily treatable.
Abnormally low blood sugar that occurs before you eat, especially if it's been several hours since your last meal or snack, is known as fasting hypoglycemia.
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Various hormones in your body work together to control your blood sugar and maintain it within a specific range throughout the day. That allows your brain to have a steady supply of glucose to function. In healthy individuals, fasting blood sugar usually stays between 70 and 99 milligrams per deciliter (mg/dL).
However, you can experience symptoms of hypoglycemia if your blood sugar dips below 70 mg/dL, according to the Endocrine Society. Typical symptoms include hunger, sweating, nervousness and shakiness. Symptoms can become more severe if your blood sugar drops even more. You may experience dizziness, sleepiness, confusion or difficulty speaking, and you'll likely feel anxious or weak if your blood sugar drops below 55 mg/dL.
Sudden shaking and sweating can occur because, when your blood sugar is low, your body releases hormones like glucagon and epinephrine to help bring it up. The shaking and sweating symptoms are side effects of the epinephrine.
Who's at Risk
True fasting hypoglycemia is not common in healthy people because your body is efficient at regulating blood sugar, even when you skip a meal or don't eat for a day or two. Most often, symptoms occur if you're taking certain medications. These medicines can potentially contribute, according to an October 2013 article in the Journal of Clinical Endocrinology & Metabolism:
- Salicylate medications, used for pain relief
- Sulfa-based antibiotics
- Pentamidine, used to treat a serious type of pneumonia
- Quinine, used to treat malaria
Alcohol can also be a trigger.
Hypoglycemia is more likely to occur in someone with diabetes. "Some oral diabetes medications work by stimulating your insulin to work better," says Erin Charboneau-Palma, RD, a dietitian and certified diabetes care and education specialist with Kelly's Choice in Skaneateles, New York. "That in turn lowers your blood sugar, and hypoglycemia can be a side effect."
"It's especially important that you don't skip meals with these meds or if you take insulin shots," she says.
If you're otherwise healthy and often experience hypoglycemia, it's important to talk to your doctor. Other rare but serious reasons for low blood sugar include illnesses that affect your pancreas, liver or kidneys.
What to Do
Hypoglycemia can catch you off guard if you get busy and forget to eat. If you start sweating and shaking all of a sudden, it's important to stop and eat or drink something to boost your blood sugar.
Carbohydrates have the most significant effect on your blood sugar, so eating or drinking a carbohydrate-rich food or beverage should ease your symptoms and raise your blood sugar within a few minutes.
Foods high in carbs include:
- A piece of fruit
- A piece of bread, or a handful of crackers or pretzels
- A glass of chocolate milk
- A 4-ounce glass of juice or sweetened soft drink (not diet)
- A handful of jelly beans or gumdrops
If you have diabetes and experience low blood sugar symptoms, the American Diabetes Association recommends eating 15 grams of carbohydrates, waiting 15 minutes and checking your blood sugar. Repeat this until your blood sugar comes up to at least 70 mg/dL.
How to Prevent Hypoglycemia
To prevent hypoglycemia, try not to skip meals. Also, pack a snack if you'll be busy and unable to stop for a meal, especially if you're drinking alcohol or taking medications that can trigger hypoglycemia.
Palma advises eating a snack that includes both protein and carbs — a combination that will help keep your blood sugar more stable until your next meal. Good options include cheese and crackers, nut butter and rice cakes or fruit and nuts.
Feeling shaky when you haven't eaten can be dangerous if you're driving or doing something that requires focus and concentration. Steer clear of hypoglycemia by not skipping meals and traveling with a healthy snack. If it happens often, talk to your doctor to rule out any health problems.
Read more: The 8 Best and Worst Foods for Reactive Hypoglycemia
- Endocrine Society: “Hypoglycemia”
- Journal of Clinical Endocrinology & Metabolism: “Non-diabetic Hypoglycemia”
- Erin Charboneau-Palma, RD, CDN, CDCES, herbalist, registered dietitian and certified diabetes care and education specialist, Kelly’s Choice, Skaneateles, New York
- American Diabetes Association: “Hypoglycemia (Low Blood Sugar)”
Is this an emergency? If you are experiencing serious medical symptoms, please see the National Library of Medicine’s list of signs you need emergency medical attention or call 911.