What is low blood sugar?
Low blood sugar, also known as hypoglycemia, can be a
dangerous condition. Low blood sugar can happen in people with diabetes who
take medicines that increase insulin levels in the body. Taking too much
medication, skipping meals, eating less than normal, or exercising more than
usual can lead to low blood sugar for these individuals.
Blood sugar is also known as glucose. Glucose comes from
food and serves as an important energy source for the body. Carbohydrates — foods
such as rice, potatoes, bread, tortillas, cereal, fruit, vegetables, and milk —
are the body’s main source of glucose.
After you eat, glucose is absorbed into your bloodstream,
where it travels to your body’s cells. A hormone called insulin, which is made
in the pancreas, helps your cells use glucose for energy. If you eat more
glucose than you need, your body will store it in your liver and muscles or
change it into fat so it can be used for energy when it’s needed later.
Without enough glucose, your body cannot perform its normal
functions. In the short term, people who aren’t on medications that increase
insulin have enough glucose to maintain blood sugar levels, and the liver can
make glucose if needed. However, for those on these specific medications, a
short-term reduction in blood sugar can cause a lot of problems. Your blood
sugar is considered low when it drops below 70 mg/dL. Immediate treatment for
low blood sugar levels is important to prevent more serious symptoms from
are the symptoms of low blood sugar?
Symptoms of low blood sugar can occur suddenly. They
- blurry vision
- rapid heartbeat
- sudden mood changes
- sudden nervousness
- unexplained fatigue
- pale skin
- difficulty sleeping
- skin tingling
- trouble thinking clearly or
- loss of consciousness, seizure,
People with hypoglycemic unawareness do not know their blood
sugar is dropping. If you have this condition, your blood sugar can drop without
you noticing it. Without immediate treatment, you can faint, experience a
seizure, or even go into a coma.
Very low blood sugar is a medical emergency. If someone you
know has diabetes and they’re experiencing mild to moderate symptoms, have them
eat or drink 15 grams of easily digestible carbohydrates, such as:
- half a cup of juice or
- 1 tablespoon of honey
- 4 or 5 saltine crackers
- 3 or 4 pieces of hard candy
or glucose tablets
- 1 tablespoon of sugar
If someone is having a severe reaction, such as
unconsciousness, it’s important to administer a medication called glucagon and
contact emergency services immediately. People who are at risk for low blood
sugar should talk to their doctor about getting a prescription for glucagon.
You should never give an unconscious person anything by mouth, as it could
cause them to choke.
What causes low
Low blood sugar can occur for a number of reasons. It’s
usually a side effect of diabetes treatment.
Diabetes and low
Diabetes affects your body’s ability to use insulin. Think
of insulin as the key that unlocks your cells, letting glucose in for energy.
People with diabetes use a variety of treatments to help their bodies use the
glucose in their blood. Among these are oral medications that increase insulin
production and insulin injections.
If you take too much of these types of medications, your
blood sugar may drop too low. People also sometimes experience low blood sugar
when planning to eat a big meal, but then they do not eat enough. Skipping
meals, eating less than normal, or eating later than normal but taking your
medication at your normal time can also lead to low blood sugar levels.
Unplanned excess physical activity without eating enough can
also cause a drop in blood sugar levels.
Drinking alcohol when you’re on these medications can also
lead to low blood sugar, especially if it replaces food. When the body is
trying to get rid of alcohol it becomes worse at managing blood sugar levels.
Other causes of low
You don’t have to have diabetes to experience low blood
sugar. Some other causes of low blood sugar include:
- certain medications, such as
- some medical conditions, such
as hepatitis or
- a tumor that produces excess
- endocrine disorders, such as
adrenal gland deficiency
How is low blood
If you suspect you have low blood sugar, it’s important to check
your blood sugar right away. If you don’t have a meter and you’re on diabetes
medications that increase insulin, talk to your doctor about getting a blood
glucose meter. If you experience low blood sugar often — say, a few times a
week — see your doctor right away to determine why. Your doctor will begin your
visit by taking your medical history, asking questions about your eating
habits, and learning more about the symptoms you’re experiencing.
If you don’t have diabetes but suspect you have hypoglycemia,
talk to your doctor about your symptoms. They will perform a physical
examination. They will use three criteria, sometimes referred to as “Whipple’s
triad,” to diagnose low blood sugar. These include:
- Signs and symptoms of low blood sugar: Your
doctor may require you to fast, or abstain from drinking and eating for an
extended period of time, so they can observe your low blood sugar signs and
- Documentation of low blood sugar when your signs
and symptoms occur: Your doctor will perform a blood test to analyze your blood
sugar levels in a laboratory.
- Disappearance of the signs and symptoms of low
blood sugar: Your doctor will want to know whether the signs and symptoms go
away when your blood sugar levels are raised.
Your doctor may send you home with a blood glucose meter — a
small, handheld blood testing device — to track your blood sugar over time at
home. They will give you instructions to test your blood sugar during certain
times of the day, such as after waking up and after eating meals. To perform a
blood sugar test, you will need to prick your finger with a lancet (provided in
your blood glucose test kit). You’ll put a small sample of blood from this onto
a strip inserted into the blood glucose meter.
If you don’t have a blood sugar testing machine on hand and
are experiencing signs or symptoms of low blood sugar with diabetes, those
symptoms may be enough to diagnose low blood sugar. Be sure to treat it right
away. Use the tips for eating 15 grams of carbohydrate described above. Test again in 15 minutes, and if your blood
sugar is not increasing, treat with another 15 grams of carbs. If your blood
sugar remains unresponsive, contact your doctor or emergency services. When in doubt, treat.
Symptoms of low blood sugar usually get worse if they’re
left untreated. Make an appointment to see a doctor if you have diabetes and
experience low blood sugar levels often, or if you have symptoms, even if you
don’t have diabetes.
How are low blood sugar
When your blood sugar levels are too low, eating something
made of carbohydrates is key. If you have diabetes, try to keep
high-carbohydrate snacks on hand. The American
Diabetes Association recommends that your snack have at least 15 grams of
carbohydrates. Some good snacks to keep on hand include:
- granola bars
- fresh or dried fruit
- fruit juice
You also can take glucose tablets to rapidly raise your
blood sugar if it’s low. These are available without a prescription. It’s
important to check how many grams are in each tablet before taking them. Aim to
get 15 to 20 grams of carbohydrates.
Wait 15 minutes after eating or taking a glucose tablet, and
test your blood sugar again. If your blood sugar is not going up, eat another
15 grams of carbohydrates or take another dose of glucose tablets. Repeat this
until your blood sugar level starts to rise. If your regularly scheduled meal
is not for a while, eat a small snack after the low blood sugar episode.
Be sure not to overeat! This could lead to blood sugar
levels that are too high.
from spells of low blood sugar
Mildly low blood sugar levels are somewhat common for people
with diabetes; however, severely low blood sugar levels can be
life-threatening. They may lead to seizures and nervous system damage if left
untreated long enough. Immediate treatment is critical. It’s important to learn
to recognize your symptoms and treat them fast. For people at risk of low blood
sugar, having a glucagon kit — a medication that raises blood sugar levels — is
important. Talk to your doctor for more information.
You may also want to talk with friends, family members, exercise
partners, and coworkers about how to care for you if your blood sugar drops too
low. They should learn to recognize low blood sugar symptoms and know how to
use the glucagon kit, as well as understand the importance of calling 911 if
you lose consciousness.
Wearing a medical identification bracelet is a good idea. It
can help emergency responders care for you properly if you need emergency
Treat low blood sugar as soon as possible. Avoid driving if
you are experiencing low blood sugar, as it can increase your risk of having an
can episodes of low blood sugar be prevented?
There are several ways that you can prevent low blood sugar.
Regularly checking your blood sugar level can help you keep
it in your target range. If you’ve had low blood sugar episodes in the past,
you may wish to check your blood sugar levels before driving or operating
machinery. Talk to your doctor about when and how often you should check your
Consider having a snack before you leave your home, if you
know it will be more than five hours until your next full meal or if your blood
sugar levels are less than 100 mg/dL. It’s a good idea to keep
carbohydrate-rich snacks on hand with you at all times in case your blood sugar
dips while you’re out and about. As mentioned above, some good choices include
granola bars, fresh or dried fruit, fruit juice, pretzels, and cookies.
Fuel during exercise
Exercise uses up energy, so it can quickly cause your blood
sugar to drop if you haven’t eaten correctly beforehand. First, check your
blood sugar one to two hours before exercise to make sure it’s within your
target range before engaging in exercise.
If it’s too low, eat a small meal or snack rich in
carbohydrates. If you plan to exercise for an hour or more, consume additional
carbohydrates during your workout. Exercise gels, sports drinks, granola bars,
and even candy bars can provide the body with a quick burst of glucose during
exercise. Work with your doctors to come up with the right program for you.
Moderate-to-intense exercise can cause blood glucose to drop
for up to 24 hours after exercise. So you should check your blood glucose
immediately after exercise and every two to four hours afterward up until you
go to sleep. Avoid intense exercise immediately before bed.
Listen to your doctor
If you follow a meal plan or take medications that increase
insulin to control your low blood sugar, it’s important to stick to the plan
your doctor gave you to prevent drops in blood sugar. Not eating the right
foods or taking the right medications at the right times can cause your blood
sugar to drop. Check in often with your doctor so they can adjust your
treatment plan when necessary.