Sleep apnea and diabetes don’t cause each other, but the two conditions are intertwined. Medical experts say each condition can influence and contribute to the other.

If you have obstructive sleep apnea (OSA), there’s a chance you have type 2 diabetes, too. Almost half of people with type 2 diabetes also have OSA. That number could be even higher since sleep apnea is highly underdiagnosed.

Understanding the link between sleep apnea and diabetes could help you better manage both conditions. It may also reduce your risk for one if you already have the other. Here’s a quick look at six ways diabetes and sleep apnea are connected.

1. Sleep Apnea and Diabetes Share Risk Factors

Sleep apnea and diabetes share many of the same risk factors, which could at least partially explain the high amount of overlap between the two conditions. The following risk factors can increase your likelihood of having both sleep apnea and diabetes.

Older Age

As you get older, your risk of health problems in general increases. More specifically, you’re at a higher risk for OSA after 40 and for type 2 diabetes after 45.

Metabolic Syndrome

Metabolic syndrome is a risk factor for both sleep apnea and diabetes. This syndrome involves a group of five conditions. To be diagnosed with metabolic syndrome, you must meet at least three of the five criteria below.

• Hypertension (high blood pressure) — A blood pressure reading of 130/85 millimeters of mercury (mm Hg) or higher
• High triglycerides — Triglyceride levels of 150 milligrams per deciliter (mg/dL) or higher
• Elevated blood sugar — A fasting blood sugar reading of 100 mg/dL or higher
• Low levels of “good” cholesterol — Less than 40 mg/dL of high-density lipoprotein (HDL) cholesterol
• A large waist circumference — A waist circumference of more than 35 inches for females and 40 inches for males, according to Cleveland Clinic

Obesity

A high body mass index (BMI) is one of the strongest risk factors for both OSA and type 2 diabetes. Up to 86 percent of people who have diabetes and obesity also have OSA.

Excess weight can compress or obstruct the airway at night, which can lead to pauses in breathing that are characteristic of OSA. As for diabetes, obesity increases the risk because it can lead to insulin resistance. When your cells don’t use insulin properly, glucose (blood sugar) has nowhere to go except your bloodstream. Over time, this can lead to hyperglycemia (high blood sugar).

Weight management can improve glucose control while also taking pressure off your airway at night. Your healthcare team may recommend strategies to manage diabetes and OSA at the same time.

2. Stress on the Body Means Less Blood Sugar Control

Sleep apnea stresses your body in two ways. The first is hypoxia, which is a reduced oxygen supply. The second is sleep fragmentation, or waking up regularly throughout the night, which impairs sleep quality. Both these stressors may affect your body’s glucose metabolism.

Hypoxia

Hypoxia causes a stress reaction inside your body. When your organs and tissues don’t get enough oxygen, inflammatory cytokines and the stress hormone cortisol are released.

Over time, high cortisol affects the way your body processes glucose. Eventually, it can decrease insulin sensitivity. This alone increases diabetes risk, but inflammation and inflammatory cytokines can also increase insulin resistance.

Sleep Fragmentation

Research suggests that poor sleep quality from OSA-related sleep fragmentation is linked to higher fasting glucose levels. Waking up repeatedly throughout the night can also activate the sympathetic (fight-or-flight) nervous system. This stress response reduces insulin sensitivity and can lead to poor blood sugar control.

If you’re constantly sleep deprived because of sleep apnea, your body isn’t able to make as many appetite-regulating hormones as it needs. This can lead to overeating and weight gain, which also increases your diabetes and metabolic syndrome risk.

Chronic sleep deprivation can also make it harder to follow your diabetes care plan. For example, you might forget to take your medications and experience poorer glucose control because of missed doses.

3. Nerve Damage From Diabetes Can Affect Nighttime Breathing

Diabetic neuropathy (nerve damage) is a diabetes complication that can develop when blood glucose is high and unmanaged. You might be familiar with peripheral neuropathy, the most common type, which causes symptoms like numbness in your hands and feet. Another type, called autonomic neuropathy, involves damage to nerves that control body processes you don’t think much about, like breathing and blood pressure.

More than one-quarter of people with diabetic autonomic neuropathy also have OSA. Nerves around the throat, tongue, and airway help control breathing as you sleep. When those nerves are damaged, the airway can become narrow or collapse and cause you to wake up repeatedly.

4. Sleep Apnea and Diabetes Affect Health Together

Just like sleep apnea and diabetes share risk factors, sleep apnea and diabetes can both increase your risk for other serious health conditions, like cardiovascular disease. Diabetes and sleep apnea can both make your cardiovascular system work overtime, leading to an increased risk of heart complications such as:

• Heart disease
• Hypertension
• Heart attack
• Heart failure
• Stroke

Both conditions can also cause more general feelings of unwellness. Sleep apnea and high blood sugar levels can both cause or worsen fatigue, for example.

5. Sleep Apnea Treatment May Improve Blood Sugar Control

Some research indicates that sleep apnea treatment may improve blood sugar control. If you already have diabetes, sleep apnea treatment can improve your diabetes management. If you have sleep apnea but not diabetes, treating it could help prevent diabetes and other associated health complications.

Continuous positive airway pressure (CPAP), the gold standard treatment for sleep apnea, helps prevent hypoxia and can reduce the number of times you wake up at night. CPAP therapy involves wearing a mask over your nose and mouth. The CPAP machine delivers consistent air pressure through the mask into your airway so it stays open and doesn’t collapse while you sleep. When used properly and worn all night, CPAP supports continuous nighttime breathing so your body gets the oxygen it needs.

More consistent sleep with CPAP means higher oxygen levels for your body and better sleep quality. Not only can it manage your sleep apnea, but it can also increase insulin sensitivity and improve glucose metabolism.

CPAP isn’t the only sleep apnea treatment that might improve your diabetes. Alternative treatment options like an implantable nerve stimulator might help with autonomic neuropathy so you can breathe easier, sleep more soundly, and maintain better control over your blood sugar. And, of course, lifestyle changes for weight management may also help with both conditions.

Talk to Your Doctor

If you have sleep apnea and diabetes, work closely with your healthcare team to manage both. Keeping both conditions under control can help in the short and long term. With steadier blood sugar and more restful sleep, you may have more energy and feel less tired or drowsy.

In the long term, managing your sleep apnea and diabetes could lower cardiovascular risks and increase your life expectancy. A comprehensive treatment plan can reduce your risk for conditions related to OSA and diabetes and improve your quality of life.

Join the Conversation

On MySleepApneaTeam, people share their experiences with sleep apnea, get advice, and find support from others who understand.

How do you manage sleep apnea and diabetes together? Let others know in the comments below.