The surprising connections between sleep and CTS
I become interested in carpal tunnel syndrome when researching a few weeks ago a blog on Why Your Arms Go Numb At Night.
When you think of carpal tunnel syndrome, what comes to mind? For most of us, it’s probably a person toiling away at a keyboard. This painful condition that affects the arms, wrists and hands is strongly associated with overuse and overwork at a computer.
But there’s a lot more to carpal tunnel than the dangers of too much typing (though that is one very real carpal tunnel cause). How we sleep at night may be another factor that contributes to our risk of developing carpal tunnel. And once the condition presents itself, it poses a number of serious challenges to sleep.
What is carpal tunnel?
Carpal tunnel syndrome is a condition that causes sensations of tingling, numbness, and pain in the hand and arm. These uncomfortable, painful sensations are the result of excessive pressure on the median nerve, which runs through the arm and wrist to the hand.
The median nerve is a major nerve that helps control some hand muscles and delivers feeling to our fingers. As it travels through the arm to the hand, the median nerve passes through the carpal tunnel, which is a narrow opening at the wrist. This small tunnel can become narrowed, which leads to compression and pressure on the median nerve.
In addition to pain, numbness, and tingling, symptoms of carpal tunnel syndrome include:
- Burning, itching sensations in fingers and hand
- Fingers that feel swollen and clumsy
- Pain and tingling that travel up the arm
- A strong urge to shake out hands to relieve discomfort
- Diminished strength and dexterity in hands, including difficulty with grip
Symptoms of carpal tunnel often first present themselves at night, in the form of numbness or tingling in the arm or hand. As the condition progresses, nighttime continues to be a time when carpal tunnel symptoms can be at their worst. Painful carpal tunnel symptoms often interfere with sleep.
What causes carpal tunnel syndrome?
Carpal tunnel is a relatively common condition that affects millions of adults. A recent study estimated that nearly 8 percent of working adults in the United States suffers from carpal tunnel syndrome.
Women are at significantly higher risk for developing carpal tunnel. Research shows women are at three times more likely to develop carpal tunnel than men. One possible reason for this is that the carpal tunnel in a woman’s wrist is smaller, making median nerve compression more likely. People with certain health condition, including diabetes and thyroid disorders, are also at higher risk for the condition. Other risk factors for carpal tunnel syndrome include:
Repetitive use. People who engaged repeatedly in the same hand and wrist actions are at greater risk for carpal tunnel syndrome. That can be anything from carpentry and assembly work to typing and data entry. Research shows people who use vibrating hand tools repeatedly are particularly vulnerable to carpal tunnel.
Positioning of hand and wrist. Actions or positions that involve significant flexing or extending of the hand or wrist put pressure on the median nerve, and over time can lead to the development of carpal tunnel.
Trauma or injury. Injuries or trauma to the wrist, including sprains and fractures, can affect the carpal tunnel and contribute to compression of the median nerve.
Health conditions. In addition to diabetes and thyroid conditions, other health conditions can heighten risk for carpal tunnel syndrome. These include rheumatoid arthritis, an overactive pituitary gland, and cysts or tumors in the wrist. Women may be at particular risk for carpal tunnel during pregnancy and menopause, as a result of fluid retention.
Genetics. Hereditary traits can make the condition more likely.
The condition is typically progressive, meaning it gets worse over time if left untreated. Letting symptoms of carpal tunnel go untreated can lead to permanent nerve and muscle damage in the hands.
Does sleep position cause carpal tunnel?
Recently, prompted by a question from my son, I talked about a common sleep phenomenon many of us experience: why our arms go numb during the night. This uncomfortable loss of sensation is what’s known as paresthesia. (Informally, of course, we all refer to it as having our arm, leg, hand or foot “fall asleep.”)
Why does this occur? There are a number of possible reasons, but nighttime paresthesia often is the result of a nerve being compressed because of a sleep position that leads us to sleep with a wrist flexed or otherwise under sustained pressure or stress.
It’s an incredibly common sleep experience. Sleep scientists and others have wondered: does sleep position cause carpal tunnel syndrome? There is some research that explores this question of a causal relationship between sleep position and carpal tunnel. Some studies have found a strong association (though not a direct cause and effect relationship) between a side-sleeping position and the development of carpal tunnel syndrome, in men and in women.
Other research, including a recent study, report that other factors—specifically a higher body mass index and a flexed wrist during sleep, but not a side-sleeping position–are associated with nighttime paresthesia in people both with and without carpal tunnel syndrome.
These mixed results point to a relationship between sleep position and carpal tunnel that is not yet well understood. Given the frequency of the condition, and the level of pain, discomfort, and sleep disruption that can result from carpal tunnel, I hope we’ll see more attention paid to gaining a better understanding of how sleep position can affect the onset and progression of the condition.
How carpal tunnel syndrome disrupts sleep
People with carpal tunnel syndrome often struggle mightily to get enough sleep, and to sleep soundly throughout the night, for a number of reasons. Carpal tunnel symptoms are often worse at night. Lying down and moving very little can lead to the accumulation of fluid in the arm and hand, which puts additional pressure on the median nerve. Sleep position, especially how the wrist is positioned throughout sleep, can make symptoms worse and cause painful flare ups that wake people from sleep.
Most people with carpal tunnel syndrome—an estimated 80 percent, according to one study—have nighttime symptoms that cause them to wake at night. The result? Heightened difficulty with their ability to function normally during the day. This is a hallmark challenge that goes with chronic pain conditions. Another consequence of the poor sleep that often accompanies chronic pain? A greater sensitivity to pain and less resilience in one’s ability to manage the emotional challenges that often accompany chronic pain conditions.
Unfortunately, there’s been relatively little attention paid to the impact of carpal tunnel syndrome on sleep, including how it might further the progression of the condition, and lead to other health issues. That’s surprising, considering all we know about the significant two-way street between sleep and pain. As I said, I hope we’ll see this change soon!
Research does show that carpal tunnel has negative consequences for sleep, by a number of important measurements. A 2014 study found that carpal tunnel syndrome significantly reduced both sleep quality and sleep quantity. Among the carpal tunnel patients included in this study, researchers found they averaged a total sleep time of only 5.5 hours a night—that’s 2.5 hours less than the minimum general recommended nightly sleep amount of 7 hours. The study also found:
- Significant impairments to sleep quality among a majority of carpal tunnel patients
- Symptoms of carpal tunnel syndrome lengthening the time it took patients to fall asleep
- A correlation between the severity of carpal tunnel symptoms and the severity of sleep disturbances, including the number of nighttime awakenings
- Carpal tunnel patients more likely to feel a need to use sleep medications to cope with their sleep problems
Earlier research demonstrated similar results, showing carpal tunnel patients suffering poor sleep quality and more fragmented sleep, as well as higher degrees of daytime sleepiness.
And two studies released in 2018 show the positive impact treating carpal tunnel syndrome can have on sleep. Both studies (which were conducted separately) examined the effects of carpal tunnel surgery on sleep, and found significant, immediate, and lasting improvements to sleep quality after surgery to relieve the impacted median nerve.
Ways to improve sleep when you have carpal tunnel
Severe cases of carpal tunnel syndrome that can’t be improved with other treatments may require surgery. But non-surgical options are almost always explored first. In cases where inflammation is believed to be a cause of carpal tunnel, physicians may recommend corticosteroid treatments or use of non-steroidal anti-inflammatory medications (NSAIDs).
For many people with carpal tunnel, there are a number of non-surgical, non-pharmaceutical treatments that can bring about relief—and all of these treatments are likely to help improve sleep as they help ease symptoms of the condition. They include:
Wrist braces. Wearing a wrist brace at night can help hold the wrist in a stable position, preventing it from flexing. Wrist braces or splints are also used by people with carpal tunnel during the day. Nighttime use of a wrist brace may help you sleep more comfortably and soundly, and reduce your pain-related awakenings throughout the night.
Hand and wrist exercises. Recent research suggests that physical therapy is as effective as surgery in treating carpal tunnel syndrome. Seeing a physical therapist may bring lasting alleviation of symptoms that will deliver significant benefits for both daytime functioning and nighttime sleep.
There are simple stretching and flexibility exercises that physical therapists recommend people with carpal tunnel perform throughout the day. Here are a few suggestions. It’s important to talk with your doctor or physical therapist about your carpal tunnel symptoms and discuss using these exercises as one part of your treatment plan. Take it easy, and don’t push too hard or try to work through pain with these exercises, if you’re trying some simple ones at home.
Resting between repetitive movement activities. For people who suffer from carpal tunnel as a result of repetitive movement, taking regular breaks can reduce symptoms. This may help reduce the nighttime symptom flare ups that disrupt sleep.
Acupuncture. A 2011 study showed that a 4-week course of acupuncture provided lasting improvements to carpal tunnel syndrome in people with mild to moderate cases. Acupuncture has been demonstrated in studies to improve sleep, including as an effective treatment for insomnia. There is evidence acupuncture can improve sleep in people who are experiencing chronic pain.
In addition, try these sleep strategies for resting more soundly with carpal tunnel:
Be consistent. There’s no more important sleep tip than this one—for everyone. Falling asleep and waking up at the same time makes it easier to sleep well. For people with carpal tunnel syndrome, who so often struggle to get the rest they need, every sleep advantage matters. A consistent sleep schedule will help give you a leg up on getting the high-quality sleep you’re looking for.
Choose your sleep position with care. For people with carpal tunnel, protecting your wrist from flexing during sleep is important. That’s usually done most effectively by using a wrist brace at night. As I’ve discussed above, sleep position may contribute to the onset and progression of carpal tunnel syndrome. And a sleep position that strains or puts pressure on your wrist can certainly exacerbate pain.
For some people, a side sleeping position may increase the likelihood of your wrist becoming bent or put under pressure. (This may be particularly true of a fetal position, where your arms and legs curl into your body. A body pillow can help you sleep on your side without moving into a fetal position.) A stomach sleeping position may also increase the chances of wrist pressure during sleep. Everyone is different, so pay attention to what your body does at night, and take any questions or concerns to your physician or physical therapist. Whether on your back, your stomach, or your side, the best sleeping position for people with carpal tunnel is one that protects your wrists from strain and pressure throughout the night.
Get plenty of magnesium. I’ve written before about the benefits of magnesium as a natural sleep aid and pain reliever. Magnesium functions as an anti-inflammatory, and helps keep muscles relaxed and functioning normally. About half of the U.S. population is deficient in magnesium, so it’s a mineral worth paying attention to getting enough of. Magnesium is often taken as a supplement, and found in dark leafy greens, beans, whole grains, some nuts, as well as in meat and dairy products.
If you’re experiencing pain, stiffness, tingling or other discomfort in your hands or arms, don’t ignore it. Carpal tunnel is less disruptive to your life and your sleep, and easier to treat, when you start early.
Michael J. Breus, PhD, DABSM
The Sleep Doctor