Updated on September 9, 2024.
Many people with multiple sclerosis (MS) experience physical and mental fatigue. This can make it hard to complete daily tasks, have a conversation, or focus your thoughts. While several medications are available to help ease MS-related fatigue, there’s another possible reason for the exhaustion—a common sleep condition called sleep apnea.
Reasons for feeling sleepy
Fatigue is very common in people with MS. About 80 percent of people with MS experience it, according to the National Multiple Sclerosis Society. There are two main categories of fatigue in people with this condition.
First, the disease itself causes fatigue, which is called primary MS fatigue. Researchers don't fully understand the reasons behind primary MS fatigue, but changes in the brain, nervous system, and muscles play a role.
Primary MS fatigue is sometimes called “lassitude.” It often occurs in the morning (even after a good night’s sleep), it can come on quite suddenly, and it can be severe.
The other category of fatigue, which happens when an MS-related issue causes tiredness, is called secondary MS fatigue. Secondary MS fatigue can be caused by multiple issues, including bladder problems that cause nocturnal visits to the bathroom, muscle spasms, inactivity, stress, or medication side effects.
Fatigue could also be part of a completely unrelated problem. In particular, people with MS are at higher risk of developing certain health conditions, including depression, anxiety, heart disease, diabetes, thyroid disease, and inflammatory bowel disease.
Another condition linked to secondary MS fatigue is obstructive sleep apnea (OSA).
What is OSA?
Obstructive sleep apnea, the most common type of sleep apnea, occurs when the muscles inside the throat relax and the airway temporarily becomes blocked during sleep, causing a brief pause in breathing. This doesn’t just happen once, but many times while a person sleeps.
Signs of OSA include loud snoring, waking up gasping or choking, and having headaches when you wake up. OSA can also cause daytime fatigue, difficulty focusing, and shifts in mood. OSA is known to have a large impact on your overall health and wellbeing, too, potentially leading to high blood pressure and a higher risk of heart disease.
OSA and MS
Multiple small studies throughout the 21st century so far have shown clear links between OSA and MS fatigue. More research needs to be done, but so far, data has shown that between 37 percent and 56 percent of people with MS are at high risk for OSA. And it’s not always investigated and diagnosed, in part because the symptoms of OSA tend to be similar to some of the symptoms of MS.
According to a 2023 review published in Neuropsychiatric Disease and Treatment, the link between MS and OSA may in part be related to obesity. Up to 67 percent of people with MS have overweight or obesity, and obesity is linked to sleep apnea.
Diagnosing and treating fatigue caused by OSA
The results of research so far suggest that a good portion of MS-related fatigue could be reduced by finding and treating sleep apnea. Talk with your healthcare provider (HCP) about being evaluated for OSA.
Your HCP may refer you to a sleep medicine specialist for a comprehensive sleep evaluation, which usually requires spending the night at a sleep clinic.
If you have OSA, the solution could be as simple as sleeping with a special mouthpiece or a breathing device called a continuous positive airway pressure CPAP machine, which uses low pressure to keep your airway open so you can breathe and sleep better.
Other tips for fighting fatigue
If fatigue is getting in your way, you can also try these tips to improve your sleep, recommended by the Centers for Disease Control and Prevention (CDC):
- Avoid caffeine. It might give you a little boost during the day, but it can affect your sleep at night, particularly if consumed within several hours of bedtime.
- Try not to consume large meals or alcohol right before bedtime.
- Power down your laptop or TV well before you turn out the lights to go to bed.
- Ensure the room where you sleep is dark, quiet, and not too warm or cold.
- Try to manage stress and anxiety through techniques like a healthy diet, regular exercise, and meditation.
If you have MS and experience fatigue, talk with your HCP about whether you may be at risk for OSA.
