If a checkup left you wondering what "a little high" blood sugar means, you may have come across insulin resistance and asked what it feels like. This guide, written for readers across Raleigh, Durham, Chapel Hill and Cary, covers what it is, why it so often has no symptoms, the signs that can show up, how it is checked, and what the evidence says helps.
One thing up front. Nothing here lets you work out your own blood sugar from how you feel. Blood tests do that, and your own doctor reads them.
What is insulin resistance?
Insulin resistance is a condition in which your body does not respond to insulin the way it should.1 Insulin is the hormone that helps sugar move from your blood into your cells. When muscle, fat and liver cells respond poorly, sugar builds up in the blood, and the pancreas makes more insulin to keep up.2 Over time, it may not be able to.1
Cleveland Clinic says that high blood sugar can eventually lead to prediabetes or type 2 diabetes.2 The NIDDK adds that researchers do not fully understand what causes insulin resistance and prediabetes.1
It is common to hear "insulin resistance" and "prediabetes" used together, but they are not the same thing. Insulin resistance describes how your cells respond. Prediabetes is a blood sugar range.1 The NHLBI notes that metabolic syndrome, a cluster of related findings, is also called insulin resistance syndrome.3
The scale is large. The CDC reports that 115.2 million American adults, more than 2 in 5, have prediabetes, and that 8 in 10 adults with prediabetes do not know they have it.8
What are the symptoms of insulin resistance?
Most people have none. The NIDDK says people with insulin resistance and prediabetes usually have no symptoms, though some people with prediabetes have symptoms like those of diabetes.1 Cleveland Clinic agrees that early on you usually will not have any.2
When signs or clues do show up, they point toward the condition and are not proof of it:
- Darkened skin in the armpit or on the back and sides of the neck, called acanthosis nigricans.2
- Skin tags.2
- Extra fat around the belly. Cleveland Clinic describes excess fat in your belly and around your organs as raising risk.2
- Changes in blood fats. The NIDDK says the levels of fat in your blood may go up with insulin resistance or prediabetes, and doctors may check cholesterol and triglycerides.1
- A larger waistline, high triglycerides, low HDL cholesterol, high blood pressure and high blood sugar. The NHLBI lists these five as the conditions of metabolic syndrome. You may have it if you have three or more.3
Symptoms of high blood sugar itself are different, and usually appear later. The NIDDK lists increased urination, feeling very thirsty, feeling very hungry even after you have eaten, blurred vision, fatigue, sores that are slow to get better, and frequent infections.9 It says type 2 symptoms can develop slowly or be mild enough to go unnoticed.9
Notice that fatigue appears on that list, but it also appears on almost every list of everyday complaints. Tiredness alone does not tell you anything about your insulin. If you feel drained after meals in particular, see tired after eating for what else can be behind it.
What causes insulin resistance?
No single cause is known, but the NIDDK lists risk factors: having overweight, obesity or a large waist size; being 35 or older; a family history of diabetes; not being physically active; smoking or secondhand smoke exposure; and a history of gestational diabetes.1
The same page names other conditions linked with it, including polycystic ovary syndrome (PCOS), sleep apnea and Cushing's syndrome. It also lists certain long-term medicines, such as glucocorticoids and some antipsychotic and HIV medicines.1 If you take one of these, do not stop it. Ask the doctor who manages it how it fits with your blood sugar.
Cleveland Clinic adds that diets high in processed foods, carbohydrates and saturated fats can contribute, and that sleep disorders and high blood pressure or cholesterol are risk factors.2 It also says people who are Black, Hispanic or Latino, Asian or Middle Eastern may have a higher risk.2
Two more points are worth knowing:
- Risk factors are not a verdict. They raise the odds. They do not decide the outcome.
- Many of the factors are things you can influence. Food, movement, sleep and weight are the ones within reach, and the evidence on them is covered below.
How is insulin resistance checked?
Your doctor does not usually test for insulin resistance directly. The NIDDK says health care professionals may not test for it, and that the test is used primarily for research.1 Cleveland Clinic says there is no routine testing for it, so your provider looks at your medical and family history, a physical exam, and blood tests.2
The blood tests that matter in practice are:
| Test | What it shows | Prediabetes range |
|---|---|---|
| A1C | Average blood sugar over about three months | 5.7% to 6.4%1 |
| Fasting plasma glucose | Blood sugar after not eating | 100 to 125 mg/dL1 |
| Oral glucose tolerance test | Another blood sugar test your doctor may use | 140 to 199 mg/dL1 |
| Lipid panel | Cholesterol and triglycerides | Your doctor reads the results12 |
The NIDDK suggests testing for people age 35 or older, or those with overweight or obesity and other risk factors.1 If you have any of the risk factors above, or you are not sure when you were last tested, ask your doctor. The CDC says to talk to your doctor about getting your blood sugar tested if you have any risk factors for prediabetes, and to ask about CDC-recognized National Diabetes Prevention Program offerings in your community.4
What helps improve insulin sensitivity?
The main approach is steady lifestyle changes: regular physical activity, eating more whole foods, losing a small amount of weight if you carry extra, and getting enough sleep. Cleveland Clinic calls lifestyle changes the primary approach, and the NIDDK lists healthy eating, physical activity, weight management and enough sleep.12 None of this is a quick fix, and none of it replaces your doctor's advice.
Weight. In the Diabetes Prevention Program, people at high risk who lost 5% to 7% of their starting weight lowered their chance of developing diabetes.1 The CDC puts that at about 10 to 14 pounds for a 200-pound person.4 The CDC says research showed that people with prediabetes who joined a structured lifestyle change program could cut their risk of developing type 2 diabetes by 58%, or 71% for people over 60.5 That describes groups of people in a structured program, not a promise for any one person.
Movement. The CDC defines regular activity as at least 150 minutes a week of brisk walking or a similar activity, about 30 minutes a day, 5 days a week.4 Cleveland Clinic says regular moderate-intensity activity can help.2 Start where you are. A ten-minute walk after a meal counts as a beginning.
Food. Cleveland Clinic suggests more whole foods such as vegetables, fruits and whole grains, and fewer refined carbohydrates, sugar and processed starches.2 The CDC's plate method fills half the plate with nonstarchy vegetables, a quarter with lean protein, and a quarter with carbohydrate foods.10 For specifics, see what to eat with prediabetes and the anti-inflammatory food list.
Sleep. The CDC says adults 18 to 60 need 7 or more hours, and that enough sleep may lower the risk of type 2 diabetes.6 The research on fixing short sleep is early. In a small crossover study of 21 adults who slept 6 hours or less, two weeks of longer sleep showed no significant metabolic effect across the group. In the 8 people who actually slept more than 6 hours, a measure of insulin resistance improved.7 The authors suggested a minimum amount of sleep may be needed for the benefit.7
I approach this the same way I approach any whole-picture question: through food, stress, sleep, time outside and the people around you. I begin with one change and work alongside your own doctor. If you are not sure which area to start with, the Garden Check-in asks seven plain questions and takes about three minutes. For more on the practical side, see how to lower blood sugar naturally.
When should you see your own doctor?
See your own doctor if you have risk factors and have not had a blood sugar test recently, if you notice dark skin patches or skin tags, or if you have symptoms of high blood sugar. The NIDDK says to talk with your primary health care professional about any symptoms you are having and ask whether you should be tested for diabetes.9
Make an appointment for:
- Strong thirst, passing urine much more often, being hungry soon after eating, blurred vision, or sores that are slow to get better.9
- A family history of diabetes, or a past pregnancy with gestational diabetes.1
- Dark patches of skin on your neck or armpits, which Cleveland Clinic ties to prediabetes.2
- Fatigue that does not improve with rest, along with any of the above.
If you take diabetes medicines, the NIDDK says low blood glucose can be a side effect of insulin or some other medicines, and that raising your activity beyond your usual routine can lower it for up to 24 hours.11 A change in food or activity can therefore matter. Ask your doctor before you change anything, and never stop or change a medicine on your own.
Call 911 if there is fruity-smelling breath, trouble breathing, fainting, or abdominal pain, nausea or vomiting. The NIDDK describes these as possible signs of diabetic ketoacidosis, a medical emergency.9 Call 911 as well if someone who takes diabetes medicines has a seizure or loses consciousness. The NIDDK says severe low blood glucose can cause both and needs help right away.11
This article is general education from Dr. Maurice Werness, ND, and not a substitute for individual medical advice.