If your blood sugar drops below 70 mg/dL, eat or drink 15 grams of fast-acting carbohydrates right away, then wait 15 minutes and recheck. This is called the 15-15 rule, and it’s the standard first response recommended by the CDC. If your level is still below 70 after 15 minutes, repeat the process until you’re back in your target range.
How to Recognize Low Blood Sugar
Your body sends out warning signals in a predictable sequence. The earliest signs come from your nervous system reacting to the drop: shaking, a pounding heartbeat, sudden anxiety, sweating, and intense hunger. You might also feel tingling in your lips or fingers. These symptoms are your body’s alarm system, and they give you a window to act before things get worse.
If blood sugar keeps falling, the symptoms shift from physical to mental. Your brain is now running short on fuel, so you may feel confused, weak, unusually fatigued, or warm. Severe drops can cause major cognitive problems, seizures, or loss of consciousness. The transition from shaky-and-hungry to confused-and-disoriented can happen quickly, which is why treating those early warning signs immediately matters so much.
What to Eat Right Now
You need something that will raise your blood sugar fast. That means simple, quick-absorbing carbohydrates with no fat or protein to slow digestion. Any of the following will give you roughly 15 grams of carbs:
- 3 glucose tablets
- Half a cup (4 ounces) of fruit juice or regular soda
- 6 or 7 hard candies
- 1 tablespoon of sugar
After eating one of these, set a timer for 15 minutes. Recheck your blood sugar. If it’s still under 70 mg/dL, eat another 15 grams and wait again. Keep repeating until you’re back above 70. Resist the urge to eat everything in sight during an episode. Overcorrecting can send your blood sugar swinging too high, which creates its own problems.
Stabilize After You Recover
Once your blood sugar is back in range, the fast-acting carbs you just ate will burn off quickly. If your next meal is more than an hour away, eat a small snack that includes protein and complex carbohydrates to prevent another drop. A handful of crackers with peanut butter, cheese and whole-grain bread, or a small portion of chicken all work well. Research on post-exercise blood sugar management found that roughly 20 grams of protein (about the amount in 3 ounces of chicken or one scoop of protein powder) meaningfully reduced the time spent in low blood sugar ranges through the following morning.
When Someone Else Needs to Step In
If blood sugar drops low enough that a person becomes confused, loses consciousness, or has a seizure, they can’t safely eat or drink. Trying to put food in the mouth of someone who is semiconscious is a choking risk. This is when glucagon is needed.
Glucagon is a hormone that tells the liver to release stored sugar into the bloodstream. It comes in three forms: a nasal spray that works like a single puff into the nose, a pre-mixed pen similar to an EpiPen that injects through the thigh or upper arm, and a kit that requires mixing a powder and liquid before injection. The nasal spray is the easiest for a bystander to use correctly because it requires no needles or mixing. After giving glucagon to an unconscious person, turn them on their side since vomiting is a common side effect. Call emergency services any time someone loses consciousness from low blood sugar.
Common Triggers to Watch For
Understanding why your blood sugar dropped helps you prevent it from happening again. For people with diabetes, the most common cause is too much insulin or other blood sugar-lowering medication relative to what your body needs at that moment. This mismatch often happens when you eat less than usual after taking your regular dose, or when you exercise more than you typically do.
Alcohol is another significant trigger. Heavy drinking without eating can block your liver from releasing its stored glucose into the bloodstream, leaving you vulnerable to a drop that can come on hours after your last drink. For people without diabetes, a condition called reactive hypoglycemia can cause blood sugar to plunge after meals, particularly in people who have had stomach bypass surgery or other procedures that change how the stomach processes food.
Low Blood Sugar During Sleep
Nocturnal hypoglycemia is especially dangerous because you may sleep right through the early warning signs. Clues that it’s happening include restless or irritable sleep, waking up drenched in sweat, nightmares, trembling, or noticeable changes in breathing patterns. A partner may notice these signs before you do.
You’re at higher risk for overnight lows if you skip dinner, exercise close to bedtime, or drink alcohol in the evening. Prevention strategies include eating a balanced bedtime snack, adjusting the timing or dose of evening medications (with guidance from your care team), and using a continuous glucose monitor with a low-threshold alarm that can wake you before levels become dangerous.
Driving and Other Activities
Low blood sugar impairs your reaction time and judgment in ways that make driving unsafe. The American Diabetes Association recommends raising your blood sugar above 90 mg/dL before getting behind the wheel, not just above 70. If you feel symptoms while driving, pull over safely, test your blood sugar, and treat it. Do not resume driving until both your blood sugar and your mental clarity have fully recovered.
When You Stop Feeling the Warning Signs
Some people, especially those who experience frequent lows, gradually lose the ability to feel early symptoms. This is called hypoglycemia unawareness, and it means the shaking, sweating, and hunger that normally alert you to a drop become muted or disappear entirely. It’s particularly common in people who have had diabetes for many years.
The good news is that this condition is often reversible. Research shows that strictly avoiding hypoglycemic episodes for just two to three weeks can reset the threshold at which your body starts sending warning signals. This usually involves temporarily raising blood sugar targets and checking levels more frequently. A continuous glucose monitor can be invaluable here, providing real-time readings and alarms that stand in for the body’s missing warning system while awareness recovers. Structured training programs for people with hypoglycemia unawareness have been shown to improve detection of low blood sugar, reduce the frequency of mild episodes, and help people treat lows more effectively on their own.