Does your sleep positioning make the nerves in your arm cranky?
Have you ever awoken from a sound sleep unable to “find” your arm in space? Have you noticed that when you wake up in the middle of the night, your fingers are numb and tingling? You may be sleeping in positions that stress the nerves in your neck or arm. Your nerve(s) may have reached its tipping point, signaling that it has had enough compressive stress and can no longer tolerate that position. Our body has this wonderfully efficient system to alert us to make a change–before permanent nerve damage occurs.
There are numerous studies in the literature that describe correlations between sleep positioning and carpal tunnel but actually, any of the peripheral nerves are subject to it. It all depends on how you sleep. We now know that low magnitude compressive stress applied to a nerve over a long period of time may cause significant changes secondary to impairment of blood flow, alteration in nerve conduction, and altered axonal transport. We have all heard about the relationship between carpal tunnel and how we sit at our computers all day. Consider how long we may maintain stress to a nerve when we are in a deep sleep and static position for up to 6-8 hours.
Here are some guidelines that may help you keep your nerves happy while you sleep:
- Consider your head like a 10# bowling ball; don’t put it on your hand or forearm!
- Avoid sleeping with your elbow bent more than 90 degrees. Your ulnar nerve controls sensation to your small and ring fingers. It wraps around the inside of your elbow. When you flex your elbow for sustained periods of time, it takes on tremendous strain.
- Avoid night time fisting if you can. Closing the fingers into a fist jams the intrinsic hand muscles and tendons into the carpal tunnel where the median nerve lives. Try to keep the hand flat on a pillow.
- When sleeping on your side, place a pillow in front of you to support the whole arm, limit elbow flexion, and keep the wrist and fingers flat, in a neutral position.
- Consider sleeping on your back with your arms at your sides or on pillows to keep your elbows and wrists in an ideal position. Do not fold them across your chest.
- Stomach sleepers beware! Although there is limited data, anecdotally we know that it is hard to sleep in a prone position without the temptation of flexing your elbows under you, or worse, putting them under your head. In time, your cervical spine will become limited in its ability to sleep with that much rotation.
Start making changes while you are young to prevent the potential compression neuropathies that we see at the Milliken Hand Rehabilitation Center on a daily basis. For many young patients, simply changing sleep position will significantly improve symptoms. It’s much harder to fix as you get older.