You may not feel any symptoms from diabetes at first. That’s one reason why millions of people don’t know they have it.

High blood sugar (hyperglycemia) and high levels of insulin (the hormone that manages blood sugar levels) start to damage your body silently, many years before you’re diagnosed with diabetes. If you don’t treat it, your nerves, blood vessels, and organs take a hit. And the complications can worsen the longer it’s neglected.

The result: You risk having heart failure, a heart attack, or a stroke. You could lose your vision. You could damage your kidneys, nerves, or other vital organs.

But you can defend yourself. Healthy eating, exercise, medication, and regular checkups can help you manage your blood sugar, cholesterol, and blood pressure. Sticking with your treatment, even when you feel fine, can help you avoid serious harm.

If you don’t, these are some of the hidden dangers that may lie ahead.


These face the biggest threat from diabetes. It can be deadly.

Diabetes affects your heart and your whole circulation. That includes small blood vessels in your kidneys, eyes, and nerves, and the big ones that feed your heart and brain and keep you alive.

The damage starts with high blood sugar (glucose) and insulin levels. This sets off chain reactions that force your body to work harder to correct high blood sugar. But years of diabetes will break down those defenses.

Diabetes changes how the blood vessels in your muscles work. That can weaken your heart, your most important muscle. And if your body can’t use or get glucose and nutrients very well, your heart may have problems drawing enough energy. This can put you at risk for heart failure, which is when the heart doesn’t pump blood as well as it should.

Plus, you can have inflammation in blood vessels and throughout the body. It can lead to thicker blood and raise the risk of blood clots. Your blood vessels (endothelium) get inflamed and harmful cells may enter their inner lining. The damaged endothelium doesn’t expand or relax normally.

On top of that, most people with diabetes also have too much triglycerides and LDL (“bad”) cholesterol, and too little HDL (“good”) cholesterol. Inflamed blood vessels can trap cholesterol and form plaque, making your arteries harder and narrower. This is called atherosclerosis. The buildup of cholesterol in the arteries lowers blood flow. All of these changes make a heart attack more likely.

It’s very important to get your blood sugar, blood pressure, and cholesterol levels under control. Sometimes lifestyle changes are enough, but the right medications can help you manage and prevent these complications. You may want to see a preventative cardiologist if you have a strong family history of heart problems or cardiovascular disease.


Uncontrolled blood sugar forces your bladder to handle a lot of urine because your body retains more fluid. You may wake often at night to use the bathroom. The interrupted sleep can be one reason diabetes leaves you tired.

Or diabetes can damage your nerves so you won’t feel that your bladder is full. You could leak pee. Weakened urinary muscles can make it harder for you to empty your bladder fully. Or you may pee too much.

Poor bladder control, plus high blood sugar and immune system problems, can lead to urinary tract infections (UTIs).

When it comes to sex, men with diabetes are three times more likely to have trouble getting or keeping an erection (called erectile dysfunction). For women, their sex drive could drop, lubrication drops, and sex may hurt. Lowered blood flow or nerve problems could make it harder to have an orgasm.


When you have diabetes, your cells must work harder to use glucose. That may tire your muscles and leave you feeling spent.

Studies tie diabetes to proteins in your brain that are linked to dementia. Because of narrowed, hardened arteries, your chances of stroke are also higher. Your brain needs sugar to do its job. Repeated bouts of low blood sugar can damage the brain.

Nerve damage (known as neuropathy) happens to almost everyone with diabetes. Some parts of your body may go numb or have other problems. All organs, including your heart, rely on healthy nerves. Pain in your feet and legs is a common sign that something isn’t right.

You may not notice small cuts or sores at first. Those small injuries can grow into big wounds.

Since diabetes affects your blood flow and immune system, a small sore may not get what it needs to heal. In severe cases, doctors may need to amputate a foot or other affected areas.


Compared to someone without diabetes, you’re 2 to 3 times more likely to get depressed.

There can be many reasons why. Stress hormones can affect your blood sugar level. And dealing with an ongoing health condition can be stressful. It can dim your mood and make it tough to get and stay motivated. That makes self-care harder. And that, in turn, can worsen your condition. It can be a cycle that’s hard to break.

Plus, you might feel angry, ashamed, or anxious about your condition. You could feel burned out by dealing with it all -- or in denial.

So along with all the things you’re doing to take care of your blood sugar, notice how you’re feeling emotionally.

Tell your doctor if you feel down a lot or if you have little energy. And let them know if you can’t sleep or you’ve lost interest in things you used to find fun. They may recommend adding an antidepressant and mental health counseling to your diabetes management plan.


Diabetes is the top cause of blindness in American adults. One reason is diabetic retinopathy, which slowly destroys your light-sensitive retina and macula, which you need for good vision. Uncontrolled diabetes also can lead to glaucoma and cataracts. All those conditions can hurt your eyesight.

Think about your eye like a camera. The front part is the lens. The back part, or the retina, is the film. That’s where you process vision. When your blood sugar is high for months or years, blood vessels of the retina can swell and leak fluid or blood.

At first, you may see just fine. But as time passes, your vision starts to blur. If the center of the retina swells from leakage and bleeding, it’s called macular edema. You may not be able to read small print or even the words on road signs.

In some people, the retina will grow new, abnormal vessels to scrounge for more food and oxygen. That’s called proliferative diabetic retinopathy. These new blood vessels break easily and trigger more bleeding. You may get spots that block some or all of your vision. You could get lumps of scar tissue in your eye. That can cause your retina to detach from the nerve that goes to your brain. If that happens, you can lose your eyesight totally.

Get your eyes checked. See an ophthalmologist, who can check for blood vessel damage even if you don’t have symptoms. You may need follow-up visits every few months or once a year, depending on your case.


Your vision isn’t the only sense that’s at risk. Diabetes doubles your chances for hearing loss. Prediabetes ups your chances by 30%. Experts aren’t sure why. The reason could be nerve damage, but more research is needed to know for sure.

You may lose your hearing slowly so that you aren’t even aware. If you ask people to repeat themselves a lot, get your hearing checked.

Diabetes even affects the nerves that handle these senses. If you take insulin, you may be more likely to have trouble noticing scents. This may make food taste “off.” You may even catch a whiff of something that’s not there.

Experts suspect it could stem from nerve damage or a glitch that starts in the brain. It may be an early sign of trouble with thinking skills. People who have Alzheimer’s disease or dementia often report problems with their sense of smell before their diagnosis.


Just like in the heart, the complications here are caused by damaged blood vessels in the kidneys. Over time, high blood sugar harms blood vessels walls and kidney cells, making them thicker and unable to filter your blood. When your body can’t remove waste and water as needed, you hang on to extra fluid and toxins in your blood and you lose important proteins in your urine.

In time, you may get diabetic kidney disease. It’s also called diabetic nephropathy. Your kidneys won’t be able to filter out waste very well. They could eventually stop working. If so, you’ll need dialysis or a kidney transplant.


Your white blood cells are key parts of your immune system. But they can’t do their job right if they’re flooded with glucose. You may not fight off infections as easily.

Every part of your body needs oxygen and nutrients, including your immune system. If you also have poor circulation, infections and wounds don’t heal as quickly. Also, your wounds won’t heal as quickly if your circulation is poor.

Having diabetes makes you more likely to get serious complications from flu that could send you to the hospital. Your immune system needs all the help it can get.


The state of your skin is an early tip-off for diabetes. Poor circulation, weak immunity, or insulin resistance all can take a toll on your skin. You might get dry and itchy. You may have spots on your skin called diabetic dermopathy. Red, painless patches appear on the front of your legs.

You may get more bacterial and fungal infections. Parts of your skin can swell and feel painful and hot. It can happen on your eyelids, hair follicles, nails, and tissue under your skin. Yeast can make your legs itch.

If you’re obese and insulin resistant, you may see dark, raised patches on your neck, armpits, groin, or other parts of your body. You may get skin tags. This is called acanthosis nigricans.

If your blood sugar and triglycerides are both high, you can get small, red bumps called eruptive xanthomatosis.


Peering into your mouth can be one way to catch early signs of diabetes. Everyone has a yeast called candida in their mouth. It can get out of control with a weak immune system and end with a yeast infection. It also can feed on the extra glucose in your saliva.

Bacteria that settle on your tongue can cause constant bad breath (halitosis). Nerve problems can leave your mouth feeling like it’s burning.

High blood sugar can hasten tooth decay and loss and can make it harder to treat gum disease. Blood vessel changes, ongoing infections, and inflammation can destroy the tissue around your teeth. Smoking can make all this even worse.


Long-term high blood sugar can damage the nerves in your that signal when it’s time to pass what you ate down to your intestines. So partly digested food can sit in your belly for hours or days. This is diabetic gastroparesis. You may feel stuffed and nauseated and vomit.

Diabetes and obesity can also upset the balance of “good” and “bad” gut bacteria. Doctors call this dysbiosis. Too much bad bacteria can hamper how your body digests food and cause inflammation in your gut. Some experts think this could jump-start type 2 diabetes and worsen blood sugar control.