Everything You Need to Know About Type 1 Diabetes

Learn about glucose, insulin, monitoring and management.

Everything You Need to Know About Type 1 Diabetes

You may know type 1 diabetes as a disease of the young. In fact, it used to be called juvenile-onset diabetes because it’s usually diagnosed in children, teenagers and young adults. But although symptoms typically show up in young people, type 1 diabetes can develop in adults, as well. 

Unlike type 2 diabetes, lifestyle choices such as diet and exercise won’t impact someone’s risk of developing type 1 diabetes. Its exact causes are a mystery, but it’s thought type 1 diabetes is caused by a combination of genetics and environmental exposure. It’s also much less common than type 2—only about 5 percent of all cases of diabetes are type 1 diabetes. 

Glucose and insulin 
Both type 1 and type 2 diabetes are caused by problems with the way the body processes insulin. Insulin is a hormone produced in the pancreas; it helps draw glucose (sugar) from the blood and into the cells for use as fuel. In those with type 1 diabetes, the immune system attacks the cells in the pancreas that produce insulin, so the body either produces no insulin or not enough. 

When cells can’t draw glucose out of the blood stream, it builds up, leading to a condition called hyperglycemia. An excessive buildup of blood sugar leads to diabetes. 

Type 1 diabetes symptoms 
Type 1 diabetes onset can be gradual or sudden and severe, with symptoms including extreme thirst, fatigue, frequent urination, weight loss and blurred vision. 

Some people can develop diabetic ketoacidosis, as well. When the cells can’t burn glucose for energy, they burn fat. This process releases molecules called ketones, which make the blood acidic. Additional symptoms of diabetic ketoacidosis include nausea and vomiting, abdominal pain, difficulty breathing, breath that smells sugary or fruity and confusion.  

Diabetic ketoacidosis is an emergency. Call 911 or go to the emergency room if you notice any of these symptoms and suspect ketoacidosis to be the culprit. 

How to know if you have type 1 diabetes 
Once symptoms appear, type 1 diabetes is usually diagnosed by one of four blood tests that measure the amount of sugar in the bloodstream:  

  • The A1C test measures the average level of blood sugar over the previous two to three months. 
  • The fasting plasma glucose test measures blood sugar after an overnight fast. 
  • The oral glucose tolerance test measures the levels after fasting and an hour or two hours after drinking a glucose-rich beverage. 
  • The random plasma glucose test measures your blood sugar at any time the test is given, even if you’ve not fasted beforehand. 

Monitoring blood sugar if you have type 1 diabetes 
Once you know you have type 1 diabetes, it’s vital to monitor your blood sugar. You’ll be checking your blood sugar levels several times a day, either by pricking your fingertips and getting a reading via a blood glucose meter or by using a continuous glucose monitor. Your healthcare provider will also test your A1C levels once every few months to keep tabs on long-term control. 

Target levels, according to the American Diabetes Association (ADA), are as follows: 

  • A1C: below 7 percent 
  • Pre-meal blood sugar (also known as preprandial plasma glucose): between 80 and 130 milligrams per deciliter (mg/dl) 
  • Post-meal blood sugar, taken 1 to 2 hours after the beginning of a meal (also known as postprandial plasma glucose): less than 180 mg/dl 

One of the biggest differences between type 1 and type 2 diabetes is that everyone with type 1 diabetes will eventually need insulin. 

Intensive insulin therapy—taking three or more shots per day or using an insulin pump, as well as checking your blood sugar four or more times a day—is fairly typical for people with type 1 diabetes.  

Having too much glucose in the bloodstream is hyperglycemia, but those using insulin treatment run the risk of having too little glucose in the bloodstream—a condition known as hypoglycemia. Taking too much insulin at once, not eating enough, exercising without eating, waiting too long between meals or drinking too much alcohol increase the risk of hypoglycemia. 

Symptoms of hypoglycemia include anxiety, sweating, shaking, hunger, difficulty walking, weakness, confusion and bizarre behavior or personality changes. 

Managing your type 1 diabetes 
Getting enough exercise and maintaining a proper diet are crucial to any diabetes treatment regimen. Exercise helps clear glucose from the bloodstream and will help you maintain a healthy weight. The Centers for Disease Control and Prevention recommends at least 150 minutes of moderate-intensity exercise per week. 

It’s important to be mindful of your body’s blood glucose response to exercise, so be sure to check with your healthcare provider before beginning or altering your workout program. 

Eating a well-balanced diet is vital, too, particularly one that’s low in sodium, cholesterol and fat and high in fiber. The ADA notes that a variety of eating patterns may be helpful in managing diabetes. These include the DASH diet, Mediterranean-style diet, a low carb diet, a low fat diet, or a vegan or vegetarian diet.  

Medically reviewed in January 2019. Updated in March 2021. 

More On