Low Blood Sugar – Why It Happens and How to Manage It

That shaky feeling you sometimes get when you find yourself needing a snack right now? That might be a sign of low blood sugar, a common issue for people with diabetes.  

During digestion, sugars get broken down and released into the bloodstream for the body to either use for immediate energy or to store for later. These sugars, known as glucose, fuel the body, especially the brain. 

If you struggle to maintain normal glucose levels, you are not alone. About half of older Americans have prediabetes, and more than 25% have diabetes.

And while everyone’s blood sugar fluctuates, it’s important to prevent both ‘high highs,’ and yes, ‘low lows.’ 

Many people with diabetes have occasional bouts of low blood glucose, also referred to as ‘hypoglycemia.’ But if your blood glucose levels are dropping a lot, it’s important to understand the root causes and management strategies.  

What Are Normal Blood Glucose Levels?  

Maintaining normal blood glucose levels not only helps support your energy and mood throughout the day, but also helps prevent serious health problems down the road.  You’ll find that values are lowest first thing in the morning since you haven’t eaten in many hours.

For people without diabetes, a normal glucose level after fasting overnight is around 99 mg/dL or less. Throughout the day, after eating, a normal blood sugar reading would be below 140 mg/dL. 

For those with diabetes, targets are generally 80-130 mg/dL before a meal and below 180 mg/dL 1 to 2 hours after eating.

But how low is too low? You’re considered hypoglycemic if your glucose dips to 70 mg/dL or less. And if your blood glucose levels fall below 54 mg/dL, that’s considered severe hypoglycemia. 

These can be dangerous conditions if left untreated, so be sure to talk with your health care team and make sure you have a treatment plan in place. 

Top 8 Causes of Low Blood Glucose Levels 

Here are some of the most common reasons behind drops in blood sugar: 

1. Taking too much or the wrong type of insulin or other diabetes medications 
2. Taking insulin at the wrong time based on how quickly your meal or snack is absorbed 
3. Not eating enough carbohydrates 
4. Skipping meals 
5. Drinking too much alcohol 
6. Exercising more than usual 
7. Fasting for a medical procedure, religious purposes, or other reasons 
8. Being sick (especially nausea or vomiting that affects food intake) 

How Do I Know if I’m Too Low? 

The only way to be certain you have low blood glucose is to test it. But there are some common tell-tale signs. Just remember, everyone’s body reacts differently to hypoglycemia – your symptoms might be different from your spouse’s, friend’s or neighbor’s. Listening to and understanding your body’s signals is key.  

Some common signs of low blood sugar include: 

• Feeling shaky in the hands or throughout your body 
• Becoming clammy or sweaty 
• Being nervous, anxious, irritable or impatient 
• Feeling confused, lightheaded or dizzy 
• Quickening heartbeat 
• Feeling hungry 

Severe hypoglycemia can lead to more serious symptoms, like: 

• Weakness 
• Difficulty walking or seeing clearly 
• Confusion and strange behavior 
• Seizures 

Knowing your body’s warning signs, and what to do if you feel your blood sugar dipping, will help you maintain normal glucose levels throughout the day. It’s also good to have a few go-to moves in your back pocket if you find yourself slipping.  

Go-To Tips for Blood Glucose Management  

Follow the 15-15 rule: If you have low blood sugar, start by having 15 grams of carbohydrates. You want something quick-acting, like a glucose tablet, ½ cup (4 oz.) of fruit juice, 1 tablespoon of sugar or honey, or some gumdrops or candy. Then, wait 15 minutes. Test your blood glucose levels if you can. If they haven’t returned to normal, do another 15-15 cycle until you’re back to where you need to be. 

Think “Clockwork”: You know the expression, slow and steady wins the race? The same principle applies when it comes to maintaining normal glucose levels. You want to eat meals at regular intervals, spaced out evenly throughout the day. Steady energy throughout the day, plus eating fiber and protein along with carbohydrates, helps stabilize blood glucose and prevents those peaks and dips. And of course, never skip a meal! 

Eat Before You Zzz: If you’ve been especially active during the day, you might get the dreaded nighttime lows. Low blood glucose overnight is common, but also very preventable. Allow yourself a pre-slumber snack to promote normal blood sugar throughout the night.  

Get Help: Not sure which foods are best for normal blood glucose? 

Reach out to your healthcare provider or make an appointment with a registered dietitian to help take the guesswork out of what and when to eat.

There are plenty of meal planning resources online, but it’s always best to meet with someone who can work with your own unique needs and favorite foods. You never know – you might discover your next favorite food based on their recommendations!