Is 68 Low Blood Sugar? Symptoms and What to Do

A blood glucose reading of 68 mg/dL sits just below the widely accepted threshold of 70 mg/dL that defines hypoglycemia, so yes, 68 is technically low blood sugar. For most people, a reading in this range triggers the body’s earliest warning signals and calls for a quick corrective snack. But how much that number matters, and whether you even feel it, depends on factors that make the story considerably less simple than a single cutoff suggests.

Where the 70 mg/dL Cutoff Comes From

Most diabetes guidelines and endocrinology textbooks use 70 mg/dL (3.9 mmol/L) as the line between normal and low blood sugar. Below that number, the body typically begins releasing stress hormones like epinephrine and cortisol to push glucose back up. At 68 mg/dL you are two points into that territory, which is mild hypoglycemia by any clinical standard. The severity scale generally runs from mild (roughly 54–69 mg/dL), where you can treat yourself, to severe (below about 54 mg/dL), where you may need someone else’s help.

That said, 68 mg/dL is on the gentler end of low. Many people pass through readings in the upper 60s briefly after exercise or between meals without ever noticing. The number alone does not tell you how urgently you need to act. What matters more is the combination of your reading, your symptoms, and whether your blood sugar is still dropping.

What You Might Feel at 68

The classic early symptoms of mild hypoglycemia come from that burst of adrenaline your body releases to mobilize glucose. You might notice shakiness, a fast heartbeat, sweating, hunger, or a jittery feeling. These are called adrenergic symptoms, and they are your body’s built-in alarm system. At 68 mg/dL, some people feel all of them; others feel only a vague sense that something is off.

Cognitive effects kick in as well, and they are more consistent than most people realize. A study that induced hypoglycemia in both people with and without diabetes found that low blood sugar reliably slowed reaction times and impaired working memory, regardless of diabetes status, symptom awareness, or how long someone had been living with diabetes.¹ That means even if you do not feel the shakiness at 68, your thinking and attention are likely already a little off. This matters when you are driving, operating machinery, or doing anything that requires quick decisions.

What to Do When You See 68 on Your Meter

The standard advice is the “15-15 rule.” Eat or drink about 15 grams of fast-acting carbohydrate, wait 15 minutes, then recheck your blood sugar. Good choices include four glucose tablets, half a cup of juice or regular soda, or a tablespoon of honey. The goal is to bring your glucose back above 70 mg/dL without overshooting into a spike.

At 68, you almost certainly do not need glucagon, which is reserved for severe episodes where someone is unable to eat or has lost consciousness. For those situations, injectable glucagon kits use a 1 mg dose for adults, reconstituted in sterile water and injected into the thigh or abdomen.² Newer ready-to-use liquid glucagon autoinjectors have also been shown to be effective and safe alternatives to the traditional emergency kits, and they skip the mixing step, which makes them easier for a bystander to use under pressure.³

If your blood sugar is 68 and you have no symptoms and no reason to think it is dropping further (you are not mid-exercise, you did not just take a large insulin dose), eating a small balanced snack with some protein and carbohydrate and rechecking in 15 to 30 minutes is reasonable. Panicking over 68 is not necessary, but ignoring it and hoping for the best is not wise either, especially if you take insulin or a sulfonylurea.

Common Causes of a Reading in the Upper 60s

In people with diabetes, the most frequent cause of mild lows is a mismatch between insulin (or certain oral medications) and the glucose available in the blood. This happens when you take your usual dose but eat fewer carbohydrates than expected, skip or delay a meal, exercise more than planned, or lose weight (which increases insulin sensitivity). Conditions like kidney or liver disease and hypothyroidism can also slow the clearance of insulin from the body, making a standard dose effectively stronger than intended.⁴

Alcohol deserves a special mention. Drinking suppresses the liver’s ability to release stored glucose, which is one of your body’s main defenses against falling blood sugar. A few drinks on an empty stomach can easily push someone into the 60s, even someone without diabetes.

People who do not have diabetes can also land at 68 through what is called reactive hypoglycemia, a dip that occurs two to five hours after eating. The pattern often involves a high-carbohydrate meal triggering a delayed but oversized insulin response, which then drives blood sugar lower than it should go.⁵ This kind of low tends to resolve on its own or with a small snack, and it is usually more annoying than dangerous.

Certain medications that are not diabetes drugs can also cause hypoglycemia. Some fluoroquinolone antibiotics, for example, have been linked to drops in blood sugar even in people without diabetes, though this is rare.⁶

When 68 Does Not Feel Low and Why That Is a Problem

One of the trickier aspects of hypoglycemia is that your body can recalibrate its alarm thresholds. People who experience frequent lows, whether from tight insulin regimens or from an insulin-producing tumor, gradually stop feeling symptoms at the same glucose levels that used to trigger them. The warning symptoms shift to lower and lower concentrations, a phenomenon called hypoglycemia unawareness.⁷ Someone with this condition might feel perfectly fine at 68 and not start noticing symptoms until they are well into the 50s, at which point their cognitive function is already significantly impaired.

The good news is that hypoglycemia unawareness is at least partly reversible. Avoiding lows for a period of weeks can reset those thresholds back upward, restoring the early warning signs. If you regularly see readings in the 60s without symptoms, that is worth mentioning to your doctor. It is not a sign that your body “handles lows well.” It is a sign that your alarm system has been dulled by overuse.

The Opposite Problem: Feeling Low When You Are Not

Conversely, some people experience all the classic symptoms of hypoglycemia even when their blood sugar is technically normal or even elevated. Researchers call this relative hypoglycemia, and it tends to happen when someone who has been running high for a long time (say, glucose levels consistently above 200 mg/dL) suddenly drops to a normal range. The brain, having adapted to a high-glucose environment, interprets a rapid fall as a crisis even though the absolute number is fine.⁸

This matters practically because these episodes feel genuinely terrible and can provoke the same cardiovascular stress response as actual hypoglycemia. A person newly started on insulin or an aggressive medication regimen might feel shaky and sweaty at 120 mg/dL. It is not dangerous in the same way a true low is, but it can lead to unnecessary snacking and resistance to bringing blood sugar into a healthier range. Understanding that the sensation will fade as the body adjusts can help people stick with their treatment plan.

How Accurate Is That 68 Reading, Really?

Before treating any specific number with too much reverence, it is worth knowing that home blood glucose meters are not perfectly precise, and they are least precise in the low range. A study evaluating four different monitoring systems found that the average error in readings below 70 mg/dL ranged from about 4% to 13%, depending on the device.⁹ In practical terms, a meter reading of 68 could mean your actual blood glucose is anywhere from roughly 60 to 76. That is a wide enough band to span from “clearly low” to “not low at all.”

Continuous glucose monitors add another wrinkle. CGMs measure glucose in the interstitial fluid between cells rather than in the blood directly, and they use mathematical models to convert those readings into estimated blood glucose values. There is an inherent time lag between what is happening in the blood and what the sensor reports, and that lag increases during physical activity.¹⁰ If your CGM says 68 while you are on a run, your blood sugar may actually be higher because the sensor has not caught up yet, or it may already be lower because glucose has been dropping faster than the sensor can track. If you feel symptoms during exercise and your CGM shows a borderline number, treating it as a low is the safer bet.

None of this means you should distrust your meter or CGM. These tools are extremely useful for trend tracking and overall glucose management. But treating a single snapshot reading of 68 as gospel truth, and stressing over one or two milligrams, gives the number more authority than the technology warrants. Patterns matter more than individual readings.

Exercise and the Post-Workout Dip

A blood sugar of 68 after exercise is one of the more common scenarios people encounter, and it does not necessarily mean something went wrong. Working muscles pull glucose from the blood at a high rate, and after exercise stops, your muscles continue absorbing glucose to replenish their glycogen stores. This post-exercise uptake can keep blood sugar low for hours after a workout. If you take insulin, the risk is compounded because exercise also increases insulin sensitivity, making whatever insulin is circulating more potent.

For people without diabetes, the body usually handles this fine. The liver releases stored glucose and the pancreas dials back insulin production, keeping you from dropping too far. But if you have been fasting, if the workout was particularly long or intense, or if you take insulin or a sulfonylurea, the system can overshoot. A pre-workout snack and keeping fast-acting carbohydrates accessible during and after exercise are standard preventive measures for anyone prone to exercise-related lows.

Hypoglycemia During Pregnancy

Pregnant women sometimes see low readings on glucose tolerance tests, and the clinical meaning of those lows has gotten more attention in recent research. One study found that about 7% of women experienced hypoglycemia during an oral glucose tolerance test in pregnancy, and these women tended to be younger and leaner.¹¹ Their babies were less likely to be abnormally large but more likely to be small for gestational age. The relationship between maternal hypoglycemia during these tests and actual pregnancy outcomes is an active area of investigation.

Interestingly, hypoglycemia during a glucose tolerance test may sometimes signal an exaggerated insulin response to a sugar load, which is part of the same spectrum of insulin dysregulation that underlies gestational diabetes, just manifesting differently.¹² If you are pregnant and see a reading of 68 outside of a clinical test, the same 15-15 rule applies. But flagging recurring lows with your obstetrician is worthwhile, because the pattern may carry information about how your body is handling the metabolic demands of pregnancy.

The Emotional Weight of Low Blood Sugar

Something that rarely gets discussed outside diabetes circles is the psychological toll of hypoglycemia. Repeated episodes of low blood sugar can create a persistent fear that shapes daily decisions about food, exercise, and medication in ways that undermine overall diabetes management. Researchers describe this fear of hypoglycemia as a state of unpleasant tension, anxiety, and discomfort that includes physical symptoms like palpitations and tremors, sometimes even when blood sugar is not actually low.¹³

People dealing with this fear often respond by keeping their blood sugar higher than their treatment targets recommend. They may snack preemptively, reduce their insulin doses without consulting their doctor, or avoid exercise out of worry that it will trigger a low. The result is chronically elevated glucose levels and worse long-term outcomes, all driven by the very reasonable desire to avoid the misery of another hypoglycemic episode. If you find yourself making these kinds of trade-offs regularly, it is worth having a direct conversation with your care team. Adjusting medication timing, using a CGM with low-glucose alerts, or switching to a different insulin regimen can reduce the frequency of lows enough to break the cycle of fear.

When to Worry and When to Shrug

A single reading of 68 mg/dL in an otherwise healthy person who feels fine and is between meals is almost never an emergency. Eat something, recheck in 15 minutes, and move on. The reading becomes more significant if any of the following are true: you take insulin or a sulfonylurea; you feel symptoms; you are about to drive or do something requiring sharp concentration; you have had severe lows in the past; or the reading is part of a downward trend on your CGM rather than a standalone snapshot.

For people with diabetes, frequent readings in the 60s point to a medication or behavioral pattern that needs adjusting. The question is not just “is 68 dangerous right now?” but “why am I hitting 68 repeatedly, and what does it mean for my overall regimen?” The danger of mild lows is less about any individual episode and more about cumulative exposure: each one chips away at your ability to detect future lows, pushing you closer to the kind of severe hypoglycemia that really is a medical emergency. Keeping a log of when and why your blood sugar drops, and bringing that data to your next appointment, is one of the most productive things you can do about it.