A blood sugar level below 70 mg/dL is considered low, and if that’s where you are right now, the most important thing is to eat or drink 15 grams of fast-acting carbohydrates immediately. Below 54 mg/dL is considered severely low and can become a medical emergency. Here’s what to do, what’s causing it, and how to keep it from happening again.
What to Do Right Now
Follow the 15-15 rule: consume 15 grams of fast-acting carbohydrates, then wait 15 minutes and check your blood sugar again. If it’s still below 70 mg/dL, repeat. Keep going until your level is back in your target range. Fifteen grams of carbohydrates looks like:
- 3 glucose tablets
- Half a cup (4 ounces) of fruit juice or regular soda
Don’t overdo it. The instinct when you feel shaky and awful is to eat everything in sight, but flooding your body with sugar can send your levels too high in the other direction. Stick with the 15-gram portions and recheck.
If someone with low blood sugar has passed out, is having a seizure, or can’t swallow safely, do not try to put food or liquid in their mouth. This is when glucagon is needed. Glucagon is an emergency medication available as a nasal spray or auto-injector that a family member or friend can administer. Call emergency services immediately after giving it.
How Low Blood Sugar Feels
The earliest symptoms come from your body’s stress response kicking in. Your system floods with adrenaline to try to push sugar back into your bloodstream, which produces sweating, shaking, a rapid heartbeat, anxiety, and sudden intense hunger. These are your warning signs, and they’re actually useful. They mean your body is still able to sound the alarm.
If blood sugar continues to drop, the symptoms shift. Your brain depends on glucose as its primary fuel source, and when it doesn’t get enough, things go wrong fast: blurred vision, difficulty concentrating, poor coordination, confusion, slurred speech, and tingling in the lips or hands. At the severe end, this can progress to fainting, seizures, or loss of consciousness. The transition from “I feel a little off” to “I can’t think clearly” can happen quickly, which is why treating early symptoms matters so much.
Common Causes
For people with diabetes, the most frequent trigger is a mismatch between insulin (or other blood sugar-lowering medications) and what your body actually needs at that moment. Taking your usual dose but eating less than normal, eating later than usual, or being more physically active than expected can all tip the balance. Alcohol is another common culprit. It impairs your liver’s ability to release stored glucose into your bloodstream, which can cause blood sugar to drop even in people without underlying liver problems.
Exercise deserves special attention. Physical activity pulls glucose out of your blood and into your muscles for energy. Research shows that exercising after a meal can cause sharp drops in blood sugar, with people who have type 2 diabetes experiencing average declines of nearly 100 mg/dL during a 45-minute workout. Women tend to see steeper drops than men during exercise. In most cases, blood sugar rebounds to normal levels after the activity ends, but for people on insulin, the risk window extends well beyond the workout itself.
If you don’t have diabetes and your sugar keeps running low, that’s worth investigating. Possible causes include liver disease, kidney disease, hormone deficiencies, certain medications (including some heart and antibiotic drugs), and complications from weight loss surgery. Non-diabetic hypoglycemia is uncommon, but it does happen.
Low Blood Sugar While You Sleep
Nighttime lows are particularly tricky because you can’t feel the warning signs while you’re unconscious. Signs that it’s happening include restless or irritable sleep, waking up drenched in sweat, trembling, sudden changes in breathing, and vivid nightmares that jolt you awake. You might also wake up with a headache or feel exhausted despite a full night of rest.
If you suspect nighttime lows are happening regularly, a few strategies can help. Adjusting the timing or dose of evening medication is one of the most effective approaches. Setting an alarm to check your blood sugar in the early morning hours (typically between 2 and 4 a.m.) can reveal how often drops are occurring. Continuous glucose monitors that check levels every five minutes and trigger an alarm when sugar falls too low are especially valuable for catching these episodes before they become severe.
Why Alcohol Makes It Worse
Your liver normally acts as a backup fuel tank. When blood sugar starts to dip, it releases stored glucose to bring levels back up. Alcohol disrupts this process directly, blocking the liver from producing and releasing glucose even if your liver is otherwise healthy. This means that your body’s natural safety net stops working for as long as alcohol is in your system.
The risk is highest when you drink without eating, drink heavily, or combine alcohol with insulin or other diabetes medications. Blood sugar can continue dropping for several hours after your last drink, and the symptoms of low blood sugar (dizziness, confusion, poor coordination) overlap with signs of intoxication, making it easy for you or people around you to miss what’s actually happening.
Preventing Future Episodes
Patterns matter more than individual readings. If you’re seeing frequent lows, start tracking when they happen relative to meals, medication, exercise, and sleep. A single low reading might just mean you skipped a snack. Repeated lows at the same time of day point to something that can be adjusted, whether that’s medication timing, meal composition, or activity levels.
Keeping fast-acting carbohydrates within reach at all times is a basic but essential habit. Glucose tablets in your bag, juice boxes in the car, something on your nightstand. When your blood sugar drops, the 15 minutes it takes to find something to eat can feel very long. Having a plan and supplies already in place turns a potential emergency into a manageable moment.