context: It's normal to feel tired when you have multiple sclerosis ( MS). MS itself can make you tired. Or you could have another disorder that makes it hard for you to sleep. Insomnia, restless legs syndrome, sleep apnea, and other sleep problems happen more often in people with MS. In fact, while sleep apnea only affects about 3% of Americans overall, between 4% and 20% of people with MS have it. Sleep apnea can make you feel tired during the day. It also raises your risk of conditions like heart disease and diabetes. The right treatment can help you breathe easier, sleep better, and feel more alert during the day. When you have sleep apnea, your airway becomes blocked while you sleep. This causes you to stop breathing over and over again. That wakes up your brain to restart your breathing. When you wake up that often during the night, you can't get a good night's sleep. Sleep apnea happens more often in people who are overweight. The extra tissue falls over your windpipe while you sleep, so less air gets into your lungs. MS can make you feel too tired to exercise. Both a lack of activity and the steroid drugs you might take to control MS can cause weight gain. Sleep apnea is very common in people with MS for another reason. MS attacks myelin -- the coating that surrounds and protects nerve cells. It leaves behind scars called lesions in your brain and spinal cord. Damage from MS can make it harder for your brain to control your breathing while you sleep. Snoring is a common sign of sleep apnea. If you or your bed partner notices that you snore, choke, or gasp during the night, see your doctor. Other signs of sleep apnea are: Dry mouth when you wake up Feeling tired in the daytime Headaches in the morning Mood swings and irritability Trouble remembering, learning, or concentrating During the exam, your doctor will check your mouth, nose, and throat. You might also have a sleep study to find out for sure if you have sleep apnea and, if so, how severe it is. You'll stay overnight in a lab or use a device at home to monitor your breathing while you sleep. Sleep apnea can do more than make you feel tired during the day. If you don't treat it, it can increase your risk for the following: Accidents, such as car accidents Diabetes Heart attack Heart failure High blood pressure Irregular heartbeat Obesity Stroke It can also affect your memory and make it harder for you to think clearly. The main treatment is continuous positive airway pressure ( CPAP). You wear a mask over your nose and mouth while you sleep, and a machine gently blows air into your throat. This keeps your airway open during the night. Your doctor can help you find the right type of CPAP machine and mask. Some masks are hard to fasten, which could be a problem if you have weakness or numbness in your hands. If you have damage to nerves in your face, choose a mask that doesn't put too much pressure there. Another sleep apnea treatment is a mouthpiece called an oral appliance. This moves your lower jaw and tongue to keep your airway open. A dentist or orthodontist can fit you for one. A few changes to your daily routine can also help treat sleep apnea: If you're overweight, lose weight with diet and exercise. To keep your airway open, sleep on your side instead of your back. You can buy a special pillow to stop you from rolling over. If you smoke, ask your doctor for tips to help you quit. Smoking can make sleep apnea worse. Go over all the medicines you take with your doctor. Ask if any of your MS drugs might affect your breathing at night. If so, see if you can switch to another medicine.