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Low Blood Sugar Levels

How to Avoid Dangerously Low Blood Sugar Levels

Glucose or ‘blood sugar’ is one of the most vital macronutrients that are necessary for the proper functioning of the human body. Our body consumes carbohydrates, or in simpler words, complex molecules of sugar that are broken down to glucose during digestion. Glucose is absorbed from the intestinal lumen into the circulation and taken to the body’s cells for carrying out optimal biochemical processes.

Some primary food sources of glucose include dairy products such as milk, cheese, and butter, bread, quinoa, oats, fruits, chickpeas, kidney beans, and potatoes. Apart from dietary sources, our body can also produce glucose from fats and proteins when required.

While fructose and galactose are also simple sugars that are readily absorbed by the body, glucose is the primary source of energy that our body utilizes for maintaining life. In healthy individuals, the body produces a hormone called ‘insulin’ which is responsible for taking up glucose from the blood into the cells.

Insulin helps to maintain optimum blood sugar levels within the range of 80 to 180 mg/dl. After consuming food, our pancreas secretes insulin so that the cells can utilize or store excess blood sugar.

A level of 120 to 140 mg/dl after 2 hours of eating (Random Blood Sugar) is considered optimum. However, a blood glucose level higher than 120mg/dl after 8 hours of fasting, and 180mg/dl after 2 hours of food consumption is considered excess, or a condition is known as ‘Diabetes Mellitus’.

While an excess of glucose can pose a health risk, a comparatively low blood sugar level is considered even more dangerous. Our body requires glucose in moderate amounts so that it can perform daily functions with ease and remain healthy and active.

What is Low Blood Sugar (Hypoglycemia)? 

A blood sugar level less than 70mg/dl is considered as low, or in other terms, ‘hypoglycemia’.

As glucose is stored as glycogen in the muscles and liver, it can be released into the blood during low blood sugar levels. Despite our body’s steady requirements of glucose, it is stored in very small quantities for consumption during sleep, strenuous exercise, or prolonged fasting periods.

Our brain requires glucose as its primary source of fuel but can utilize ketone bodies when its glucose reserves are depleted. The liver can produce ‘ketone bodies’ from fats which the brain can utilize during limited glucose reserves or hypoglycemia.

Symptoms and Signs of Hypoglycemia

While healthy adults rarely feel hypoglycemic due to their glucose reserves, there are rare cases where some might suffer from low blood sugar symptoms.

While a blood sugar level lower than 70 mg/dl does not produce any signs of low blood sugar, it is still of primary concern as the responses vary from patient to patient. One patient might suffer from agitation, jitteriness, and sleepiness at 69mg/dl while another might experience the same at 55 mg/dl or lower.

These low blood sugar symptoms include:

  • Agitation or nervousness
  • Increased sweating leading to soaked clothes or bed-sheets
  • Lightheadedness or dizziness – patients might refer to this as ‘spinning’ at times
  • Nausea 
  • Numbness in digits (fingers and toes)
  • Jitteriness, palpitations, trembling, or anxiety due to increased sympathetic activity. The sympathetic nervous system is triggered in response to low blood sugar levels, which prepares the body for a ‘fight or flight situation. This, in turn, releases a hormone called epinephrine which leads to anxiety and an increased heart rate.
  • Somnolence or excessive sleeping
  • Nightmares involving screaming spells
  • Excessive hunger spells
  • Loss of energy – trouble performing simple day-to-day activities
  • Muscle weakness
  • Decreased concentration 
  • Inability to speak coherently; might stammer
  • Blurred vision
  • Behavioral changes
  • Unable to recognize surroundings or people
  • Seizures or reactive fits 
  • Unconsciousness or syncope; the patient might go into a coma due to chronic low blood sugar levels.

Most people, especially those with a diabetic patient in the family, keep a blood glucose monitor handy for routine monitoring. Many people recognize their hypoglycemic symptoms initially – especially those that involve a lack of energy or feelings of intense hunger.

Types of Non-Diabetic Hypoglycemia 

While low blood sugar levels are of significant concern in teens or adults suffering from diabetes, they can also affect healthy individuals. There are two types of non-diabetic hypoglycemia which albeit rare in healthy individuals, are necessary for adequate and timely management.

Reactive Hypoglycemia

Reactive hypoglycemia is a form of non-diabetic hypoglycemia that causes low sugar levels after eating. Your body reverts to a blood sugar level of 70 mg/dl or lowers only after a couple of hours of eating, producing low blood sugar symptoms similar to those suffering from diabetic hypoglycemia.

  • Reactive hypoglycemia is more common in people who have a history of low blood sugar levels or pre-diabetes. Pre-diabetes is a condition in which the risk of developing diabetes shortly is relatively higher than in healthy adults.
  • Other conditions such as hyperinsulinism or insulinoma – a rare pancreatic tumor – in which the body produces too much insulin in reaction to blood sugar levels, can also lead to hypoglycemia in around 10% of patients.
  • Plus, certain enzymatic deficiencies can also disrupt glucose metabolism, leading to reactive hypoglycemia.

Fasting Hypoglycemia 

Fasting hypoglycemia is another type of non-diabetic hypoglycemia that usually occurs after a prolonged fasting period of 8 hours or more.

  • It is often associated with irregular dietary habits such as too much alcohol consumption (binge drinking) or stomach bypass surgeries.
  •  Fasting hypoglycemia can also occur as a side effect of some medications. These include aspirin, quinine – an antimalarial drug – and antibiotics including sulfonamide or sulfa drug and pentamidine.
  •  Fasting hypoglycemia is also associated with multisystem illnesses such as those involving the liver, kidneys, or heart.
  • Certain hormonal deficiencies such as those of glucagon – another hormone that helps to balance glucose levels in the bloodstream along with insulin – growth hormone, and cortisol can also cause fasting hypoglycemia.

What is considered a dangerously low blood glucose level? 

Treating a blood glucose level lower than 70 mg/dl immediately can help prevent severe hypoglycemia. While a blood glucose level between the ranges of 55 – 69 mg/dl is considered significantly low, it can be managed with dietary sources containing simple carbs. These include honey, syrups, juices, and glucose tablets or gels.

But, what is considered a dangerously low blood sugar level? A blood glucose level lower than 59 mg/dl poses dangerous health risks. Severe hypoglycemia is one of the common causes of dizziness, delirium, and seizures in the absence of other systemic illnesses. If left untreated, it might lead to unconsciousness and an eventful trip to the ER.

How is Non-Diabetic Hypoglycemia Diagnosed? 

While it is necessary to consult a primary care physician for treating reactive or fasting hypoglycemia, keeping a blood glucose meter might come in handy. While a blood glucose meter is not enough for ruling out a hypoglycemic diagnosis, it can help prevent the severity of the disease.

By consulting a primary care physician, you might learn how to manage your hypoglycemia better. Plus, the diagnosis for reactive hypoglycemia differs from that of fasting hypoglycemia.

Diagnosing Reactive Hypoglycemia

Your physician or endocrinologist might order a Mixed-Meal Tolerance Test (MMTT) that measures your blood glucose level after five hours of consuming a beverage in place of a solid meal.

While the primary component is sugar, the drink also consists of proteins and fats to check for pancreatic insufficiency or enzyme deficiency. A fasting period of 8 hours is required for undertaking the test so that your test results are accurate.

In case of enzyme deficiencies, for instance, in cystic fibrosis, an autoimmune condition, it is necessary for you to consult your preventive care clinic for additional requirements.

MMT helps to check your pancreas’ response to sugar and requires a fasting period of 8 hours before consuming the beverage. In addition to MMT, your primary care physician might also order insulin blood tests or other lab work for concluding the diagnosis.

At times, your primary care physician might order an Oral Glucose Tolerance Test (OGTT) in suspicion of pre-diabetes or diabetes. Similar to MMTT, you would be required to fast for a minimum of 8 hours so that you can consume a sugar-only drink for the test.

Your primary care physician will monitor your blood glucose levels after an hour as well as after three hours to compare the two readings. If your blood sugar levels fall below 70 mg/dl after three hours of the test, a preemptive diagnosis of reactive hypoglycemia can be made.

Diagnosing Fasting Hypoglycemia

The best way to diagnose fasting hypoglycemia is to conduct a fast under the supervision of your primary care physician. While a supervised fast might not be easy for the patient, it is highly accurate and reliable.

A supervised fast requires a prolonged fasting period of 72 hours or more – can take up to five days depending on the patient’s symptoms – for an accurate diagnosis. Your primary care physician might monitor your blood glucose level vigorously and note down a minimum of two readings as well as your symptoms twice a day.

What causes Hypoglycemia in Diabetics?

In diabetes, the body is either unable to produce or use insulin for lowering blood sugar levels. In the absence of insulin, the blood sugar levels might surge. To prevent hyperglycemia or increased blood sugar levels, primary care physicians or endocrinologists might prescribe either oral anti-diabetic drugs or injectable insulin.

Too much insulin in diabetes can lead to hypoglycemia. One of the main reasons for hypoglycemia in diabetics is intensive management or skipping meals to prevent high blood glucose levels.

  • Anti-diabetic drugs belonging to a class of ‘sulfonylureas’ might trigger hypoglycemic spells. They are usually used solely or in combination with other antidiabetics such as biguanides (metformin). Sulfonylureas such as Glimepiride, Glipizide, and Glyburide (the G’s) might lead to hypoglycemia if taken more than required.
  • Poor dietary patterns such as skipping meals or taking anti-diabetic medications on an empty stomach might lead to hypoglycemia if not supported by a meal.
  • In poorly managed diabetes, patients can develop certain complications involving the eyes, blood vessels, and kidneys.
  •  For instance, if the kidneys cannot filter the blood properly during diabetic nephropathy, this might lead to a build-up of waste products. Your medications might remain in the bloodstream and lower your blood glucose level than required. Kidney failure can also predispose to diabetes in non-diabetics due to inadequate filtration.
  • Alcohol can also induce hypoglycemia as it diminishes the liver’s ability to break down sugar into glucose. Combining alcohol with anti-diabetic medications might be fatal in severe cases.
  • Other drugs such as allopurinol (used to manage Gout or increased serum uric acid levels) and warfarin can also interfere with anti-diabetic medications.

What to eat when you have low blood sugar levels

It is vital to know that low blood sugar in non-diabetics can be fatal if it is not diagnosed and treated in time. For recurrent bouts of hypoglycemia, you might need to get tested by your primary care physician for an underlying cause such as a tumor or enzyme deficiency.

Treatment of hypoglycemia varies from person to person, as well as the numbers. A blood glucose level between 70 – 80 mg/dl can be treated with immediate glucose sources such as glucose tablets or juices. Your primary care physician might advise you to alter your diet and lifestyle.

  • One hallmark of treating low blood sugar is a combination of peanut butter and crackers.
  • Crackers are an immediate resource of blood sugar that can help you manage your low blood glucose levels almost instantaneously.
  • The peanut butter will help to tone down your cravings as well as provide you with essential fatty acids and proteins for maintaining that blood sugar level.
  • To prevent low blood glucose levels, keep a jar of unsweetened peanut butter or almond butter handy.

As mentioned above, a blood glucose level between the ranges of 55 to 69 mg/dl is considered significantly low, but not low enough for you to pass out. One rule of thumb is to stock your pantry with fresh fruits and dried nuts for instant rejuvenation.

  • Consume fresh fruit juices as they are full of good carbs and unrefined or added sugar.
  • Consume bananas (shakes would do), grapes (take a couple of spoons of grape jelly), raisins, dates, or pineapples. Any fruit rich in good carbs would do. However, if you have kidney comorbidity, try not to consume fruits enriched with water in high quantities.

The 15-15 Rule

The 15-15 rule is one of the most widely used methods for treating low blood sugar levels ranging from 55 – 69 mg/dl. The 15-15 rule is pretty simple: consume 15 grams of readily absorbable carbs and monitor your blood glucose level exactly after 15 minutes. In simpler terms, the 15-15 rule is a carb to time ratio.

If your blood glucose levels are still below the optimum range or relatively lower than 70mg/dl, repeat the 15-15 rule until your target. Once your blood glucose level peaks 70mg/dl, sustain the range with the help of a proper meal or maintenance snack.

What helps low blood sugar when you are drowsy and weak, and cannot measure 15 g of carbs?

  •  Consume 4 ounces (roughly 120ml or ½ cup) of fresh juice. If you are out of fresh juice, go for a store-bought alternative or soda before you pass out.
  • A tablespoon of honey is considered ideal. However, you can even consume a tablespoon of sugar (unrefined preferably, but refined would do too) or sweet syrup.
  •  Keep jelly beans or gumdrops handy. While a handful would do, consider reading their packaging for the suggested dosing per serving.
  • Take a minimum of 3 – 4 glucose tablets or a tablespoon of glucose powder in case you are out of the aforementioned sources.
  •  Lastly, a tube of glucose gel would do too.

Some things to consider while following the 15-15 rule:

  • Avoid eating complex carbs such as lentils, legumes, or beans as they also contain fiber which might slow down digestion.
  • You might be tempted to replace candy with chocolate. Try not to do so as it also contains fat which might hinder the absorption of glucose.
  • Consult your primary care physician for treating toddlers with low blood glucose levels. The 15-15 rule is not applicable for children as their blood sugar levels can be met by consuming fewer amounts.
  • Give a minimum of 15 minutes for your blood glucose level to rise.
  • Monitor your lows throughout the day to prevent any other hypoglycemic bout.
  •  Monitor your medications and numbers during travel so that you can manage hypoglycemia in case of an emergency accordingly

Treating Chronically Low Blood Sugar Levels

If your blood sugar levels are low enough to cause a seizure, you need to make sure you have a primary caregiver to take immediate action. If you are alone but barely conscious, call 911 immediately. 

If you already have had a bout of severe hypoglycemia in the past, consult your primary care physician and inquire if you need to keep a low blood sugar remedy at bay.

Your body needs instant glucagon to counteract the effects of insulin. It does so by releasing glucose from the liver into your bloodstream. Readily prepared injections of glucagon are available for remedying extremely low blood sugar levels.

Your endocrinologist or primary care physician might provide you with a prescription for injectable glucagon if necessary. 

  • Have a caregiver nearby if you already suffer from chronic low blood sugar bouts.
  •  Keep the glucagon kit nearby or at eye level so that your caregiver can reach it.
  • Train your caregiver so that they can inject the glucagon if you are too drowsy or passed out to do it yourself.
  • Call 911 and seek immediate medical assistance after the glucagon shot.
  • Your caregiver should monitor your blood glucose level after 15 minutes to see whether you need an additional glucagon shot or a sugary snack. 
  • Your caregiver should provide you with peanut butter and crackers, or juices once you become conscious or alert.

Call 911 if you are out of injectable glucagon and need a second shot to overcome the drowsiness. Your caregiver should call 911 in the absence of a glucagon kit or if your body fails to respond to the two shots of glucagon within 20 minutes. Know that you need to call 911 even if you have recovered for proper monitoring.

Preventing Hypoglycemia 

Panicking during a hypoglycemic bout is common, especially if you lack the resources for overcoming a fainting spell. Consider the following steps for preventing low or severe hypoglycemia.

Know your Numbers!

Monitor your blood glucose level vigorously. Chart your readings at least thrice a day in coordination with your meals. For better supervision, monitor your blood glucose level after waking up in the morning and before your meals. Record your diet and the timings of medications in a diary.

Take your diary to your primary care physician during the next visit so that they can alter or maintain your insulin dosing if needed. 

Be Consistent with your Meal

A well-balanced diet is necessary for diabetics. To prevent hypoglycemia, eat a minimum of three proper meals comprising whole-grain cereals such as quinoa and oats, fruits such as apples, bananas or berries, and dried nuts.  

Snack occasionally, but wisely. Reduce your portion size and limit high-sugary beverages or sources of refined sugar. Lastly, try not to skip or delay your meals. At times, your preventive care physician might advise a low-carb and high-protein diet to prevent any surges in glucose. However, this might predispose to hypoglycemia.

Do not miss your medications

Do not alter your dosing by yourself. Abide by your doctor’s prescription and book an appointment if your readings are low quite often.

Prepare for Adversities

As mentioned above, train a family member for any adversity that might take place during your blood glucose management. Keep your neighbor’s number at the emergency dial. Call 911 immediately if your blood glucose levels fail to rise after applying the 15-15 rule twice.

Keep your medical identity card and insurance details handy. If you suffer from chronic low blood glucose levels routinely, wear an identity bracelet with your medical reference number so that the paramedics or ER medics can tally.


Hypoglycemia is preventable. Low blood sugar levels are not a death sentence. Managing hypoglycemia is a matter of time. For any concerns, feel free to write to us or consult your primary care for further guidance.

– Disclaimer –
This blog is for informational & educational purposes only, and does not intend to substitute any professional medical advice or consultation. For any health related concerns, please consult with your physician, or call 911.

Medically Reviewed

Last reviewed by Dr. Syra Hanif, M.D. on 11/29/2021

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  • About The Author

    Dr. Syra Hanif M.D.

    Board Certified Primary Care Physician

Dr. Syra Hanif is a board-certified Primary Care Physician (PCP) dedicated to providing compassionate, patient-centered healthcare.

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