It’s not always easy to recognize signs of type 2 diabetes, especially because symptoms can develop slowly — or be mistaken for something else.
For example, increased thirst may be chalked up to a hot summer, or fatigue may be interpreted as a sign of aging or stress. This is unfortunate, as even short-term high blood sugar (hyperglycemia) diminishes your quality of life.
“High blood sugar means that there is an accumulation of glucose in the blood that is not reaching its given destination in the body,” says Monet Bland, CDE, at the Joslin Diabetes Center in Boston. “Untreated hyperglycemia can lead to skin problems, gynecological problems, impotence, fatigue, and blurred vision.”
And if high blood sugar stemming from diabetes persists for a long time, you may eventually develop complications, such as vision problems (diabetic retinopathy), nerve damage (diabetic neuropathy), or kidney disease (diabetic nephropathy) that cannot be completely reversed with improved blood sugar control. (1)
“It is important to note that often times the complications of diabetes can be worse than the diabetes itself,” Bland says.
To help prevent high blood sugar, Bland says, you can monitor your food intake by:
- Keeping portion sizes in mind Limit food portions and track your caloric intake to make sure you are not consuming too many calories for your energy needs.
- Considering your diet choices Carbohydrates have the largest effect on blood glucose, so you should track your intake and reach for complex carbs that are lower on the glycemic index, Bland says.
- Incorporating exercise Exercise is known to lower blood glucose and lower insulin resistance. (2)
Type 2 diabetes can cause a wide range of signs and symptoms, including: (3)
- Fatigue even when you've slept well
- Dry mouth
- Extreme thirst
- Cloudy thinking
- Wounds that won't heal
- Frequent yeast infections
- Blurry vision
- Sleeping troubles
- Excessive urination
- Sexual problems
- Sudden and unexpected weight loss
RELATED: 7 Warning Signs of Type 2 Diabetes
If you have wounds or sores that won’t heal, you may be more at risk of developing severe infections. (4)
What Are Some of the Type 2 Diabetes Symptoms Common in Men With the Disease?
Type 2 diabetes symptoms are generally the same for men and women, but urological problems such as erectile dysfunction (ED) — the inability to achieve or maintain an erection — have been associated with all forms of diabetes, including type 2.
According to the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), estimates of the prevalence of ED in men with diabetes vary widely, from 20 to 75 percent of the U.S. population. (5)
Researchers believe diabetes causes sexual function problems in men by damaging the body's autonomic nervous system, which controls circulation. (5)
If you have the symptoms of ED, it may be a sign you have diabetes.
“Erectile dysfunction signals diabetes when there are complications present as well, and [the ED] is not due to antihypertensive medications or beta-blockers,” Bland says. She notes that ED can also be a sign of normal aging, but when it occurs as a result of diabetes, it is considered a form of diabetic neuropathy.
“An individual with a higher A1C and other diabetic complications is more likely to have erectile dysfunction,” Bland says. A1C is a two- to three-month average of blood sugar levels, and it can indicate how poorly or well you’re controlling your blood sugar.
Another urological problem associated with diabetes in men is retrograde ejaculation, or the release of semen into the bladder during ejaculation. Symptoms include reduced semen during ejaculation.
What Are Some of the Type 2 Diabetes Symptoms Common in Women With the Disease?
“Yeast is known to feed off sugar, which means that higher levels of glucose in the blood allow for the overgrowth of yeast, especially in the vaginal area,” Bland explains. “This overgrowth can then cause an infection in the vaginal area.” She notes that controlling blood glucose can reduce the risk of yeast infections.
Experts believe these vaginal infections will also lead to urinary tract and bladder infections, as both yeast and bacteria multiply when blood sugar is elevated. According to the NIDDK, chances of developing these problems appear to be higher in people who also have poor blood glucose control, have high levels of cholesterol in their blood, have high blood pressure, are overweight, are over age 40, smoke cigarettes, or are physically inactive. (5)
If You Have Any of the Symptoms of Diabetes, Should You Be Concerned?
“Individuals should be concerned and see their doctor if they ever present with the classic symptoms of diabetes,” Bland says. These include:
- Frequent urination (polyuria)
- Extreme thirst (polydipsia)
- Increased food consumption (polyphagia)
- Sudden or unexpected weight loss
- Blurred vision
- Fatigue even when you are getting quality, sufficient sleep
If you have any of the above symptoms, you should see a doctor — and keep in mind that the symptoms will not necessarily appear together all at once, Bland says, as the onset of type 2 diabetes can be gradual.
Should You Get Screened for Type 2 Diabetes?
The American Diabetes Association recommends that everyone get screened for type 2 diabetes beginning at age 45. (7)
- Being overweight or obese
- Having a family history of diabetes
- Being of certain ethnicities, such as African-American, Asian, Native Hawaiian, or Hispanic or Latino descent
- Having hyptertension
- Having had gestational diabetes (diabetes during pregnancy)
- Not exercising regularly
The Tests Typically Used to Diagnose Type 2 Diabetes
There are two main types of blood tests commonly used to screen for type 2 diabetes: fasting plasma glucose test and the HbA1c test (also called the A1C test or the hemoglobin A1C test). Other tests are also described below.
The Fasting Plasma Glucose Test
“The fasting plasma glucose test refers to an individual’s blood glucose level after fasting for a period of eight hours,” Bland says. “It is widely accepted as a diagnostic tool for diabetes.”
This test is conducted on blood drawn after your eight-hour fast. The blood is normally drawn in the morning before breakfast. (9)
This test can help diagnose diabetes and prediabetes — a situation in which your glucose levels are high, but they're not quite at diagnostic level. Individuals may choose this test over the A1C test because of the cost, Bland says.
How high your blood sugar levels are indicates whether you have diabetes: (9)
- Normal blood sugar is less than 100 milligrams per deciliter (mg/dl).
- Prediabetes (impaired fasting glucose) is diagnosed if blood sugar is from 100 to 125 mg/dl.
- Diabetes is diagnosed if blood sugar is 126 mg/dl or higher.
The A1C Test
Another type of blood sugar test that's used to diagnose type 2 diabetes is the hemoglobin A1C test.
“The A1C test is known as the gold standard and would be the most indicative of whether an individual is prediabetic or has type 2 diabetes,” Bland says.
This test measures the average glucose levels in your blood for the past two to three months. (9)
The A1C is often the preferred or primary test used to diagnose prediabetes and diabetes (both type 1 and type 2).
How often you are tested depends on a number of factors. Typically, if you have prediabetes, you will be tested once a year. If you have type 2 diabetes, you will often be tested twice a year — though that might go up to four times a year if you use insulin to manage your blood sugar or if you otherwise have trouble controlling your blood sugar. (10)
Every year, about 5 to 10 percent of people with prediabetes develop type 2 diabetes, though that percent varies depending on population and the definition of prediabetes. (11)
Keep in mind that the A1C test is not accurate in people who have anemia, and that people of Mediterranean, Southeast Asian, or African descent may have results that are falsely high or low. (12)
Unfortunately, you cannot feel your blood sugar levels rise. The only way to know for sure whether you have prediabetes or diabetes is to get a blood test.
That said, signs of hyperglycemia include frequent urination, increased thirst, blurred vision, fatigue, and headache. Untreated, other signs can include nausea and vomiting, shortness of breath, weakness, abdominal pain, and even coma. (13)
Glucose Challenge Test
Women who are pregnant may first be tested for gestational diabetes via the glucose challenge test, also called the glucose screening test. (12)
“This test is a shorter version of the Oral Glucose Tolerance Test,” Bland says.
Here, you drink a sweet liquid containing glucose and have your blood drawn one hour later. If your blood glucose is 135 to 140 mg/dl or more, your doctor will likely ask you to complete an oral glucose tolerance test. (12)
Oral Glucose Tolerance Test (OGTT)
The OGTT test is another diabetes test that's performed after you haven't eaten for about eight hours. “This test allows the physician to see just how quickly glucose is cleared from the blood,” Bland says.
The technician will take a sample of your blood and then give you a prepared sugary drink. You will then have your blood drawn every hour, so that you will end up with blood glucose level results for: (12)
- One hour after ingesting the sugary drink
- Two hours after ingesting the sugary drink
- (sometimes) Three hours after ingesting the sugary drink
If you are pregnant and have high blood glucose levels at two or more times during the checks above, you have gestational diabetes. The test can also be used to diagnose type 2 diabetes and prediabetes, though it is more expensive to perform and not as easy to give as some other tests. (12)
Bland also notes that the OGTT does not actually allow for the identification of insulin resistance.
Possible OGTT results are: (9)
- Normal: blood sugar at two hours after testing is less than 140 mg/dl
- Prediabetes (impaired glucose tolerance): 140 to 199 mg/dl
- Diabetes: 200 mg/dl or above
Random Plasma Glucose Test
This test may be done at any time to measure blood sugar levels, usually when you have severe diabetes symptoms. (9)
“The random plasma glucose test is a method that allows for the identification of high blood levels immediately, but it should not be used as a tool to diagnose diabetes,” says Bland, noting that people sometimes choose this test over others because it can be a quick means of identifying high blood glucose levels.
The test is not accurate enough to diagnose prediabetes, but it can lead to a diabetes diagnosis if your blood sugar is at least 200 mg/dl and there are other symptoms such as:
- You're urinating more.
- You're drinking more than you normally do.
- You've lost weight when you didn't mean to.
Any diagnosis is generally confirmed with a fasting plasma glucose test, an oral glucose tolerance test, or an A1C test.
Diabetes Diagnoses by the Numbers: What Your Test Results Say
If you are not pregnant, the following results indicate if you are in the normal range, or have prediabetes or type 2 diabetes: (12,7)
- A1C below 5.7 percent
- Fasting plasma glucose (FPG) at 99 mg/dl or below
- Oral glucose tolerance test (OGTT) at 139 mg/dl or below
- A1C between 5.7 and 6.4 percent
- Fasting plasma glucose (FPG) at 100 to 125 mg/dl
- Oral glucose tolerance test (OGTT) at 140 to 199 mg/dl
- A1C at or above 6.5 percent
- Fasting plasma glucose (FPG) at 126 mg/dl or above
- Oral glucose tolerance test (OGTT) at 200 mg/dl or above
What to Do if You Receive a Prediabetes or Diabetes Diagnosis
If you receive a diagnosis of prediabetes, work with your healthcare team to develop healthy diet and lifestyle habits to help prevent full-blown type 2 diabetes. Talking with your doctor is equally important if you are diagnosed with type 2 diabetes. “When a patient receives a prediabetes or a type 2 diabetes diagnosis, they should seek out a multidisciplinary approach for treatment,” Bland says.
People with type 2 diabetes should also make lifestyle changes, but talk with their doctor as well about whether they need to take medication to reduce glucose toxicity (the effect of high blood sugar on insulin production and insulin action), Bland says.
“Diet is the cornerstone of treatment for both prediabetes and type 2 diabetes,” Bland explains.
The main tenets of good diabetes management include:
- Picking diabetes-friendly foods
- Monitoring your carb intake
- Getting enough high-quality sleep
- Taking blood sugar regularly (ask your doctor how often)
- Finding exercise you love and sticking with a routine
- Identifying the proper type and dose of medication and adhering to your regimen
- Using insulin if you need it
Additional reporting by Stephanie Bucklin.
Resources We Love
Editorial Sources and Fact-Checking
- Preventing and Managing Diabetes Complications. NIH MedlinePlus. Fall 2012.
- Borghouts LB, Keizer HA. Exercise and Insulin Sensitivity: A Review. International Journal of Sports Medicine. January 2000.
- Diabetes Symptoms: When Diabetes Symptoms Are a Concern. Mayo Clinic. April 21, 2016.
- Sepsis and Diabetes. Sepsis Alliance. December 13, 2017.
- Diabetes and Sexual and Urologic Problems. National Institute of Diabetes and Digestive and Kidney Diseases. December 2008.
- Vaginal Yeast Infection. MedlinePlus. February 7, 2018.
- Classification and Diagnosis of Diabetes: Standards of Medical Care in Diabetes — 2018. Diabetes Care. January 2018.
- Diabetes Symptoms and Causes. Mayo Clinic. July 31, 2014.
- Diagnosing Diabetes and Learning About Prediabetes. American Diabetes Association. November 21, 2016.
- A1C Test. Mayo Clinic. January 7, 2016.
- Tabak AG, Herder C, Rathmann W, et al. Prediabetes: A High-Risk State for Developing Diabetes. The Lancet. June 2012.
- Diabetes Tests and Diagnosis. National Institute of Diabetes and Digestive and Kidney Diseases. November 2016.
- Hyperglycemia in Diabetes. Mayo Clinic. April 18, 2015.