Maybe You Should Break Your Arm

That’s a pretty crazy suggestion, right? As you probably guessed, we don’t mean it literally. The real suggestion is that maybe you should pretend to break your arm. Researchers have discovered a surprising benefit to broken bones. Each cerebral hemisphere (each side of your brain) primarily controls and receives sensory information from the opposite side of the body. Most of us have one hand that we predominantly use. The side of the brain that controls that side tends to have a thicker cortex (denser gray matter). That’s kind of what you really want in your brain: A nice, plush, thick and hydrated layer of gray matter. One of the unseen benefits of injuries is that the healing period encourages us to use our bodies in different ways than we normally would, all of which leads to something scientist call neuroplasticity. Again, we’re not suggesting you purposely injure yourself, but to utilize what we’ve learned from what happens when we do. We can do these things voluntarily, too.

Your brain is constantly remodeling itself

This ability is called neuroplasticity—the brain's capacity to change its structure, connections and patterns of activity in response to experience, learning, injury and changes in how we use our bodies.

Researchers have found that immobilizing one arm can produce surprisingly rapid changes in the sensorimotor cortex. In one study of people whose arms were immobilized following injury, researchers found changes in cortical thickness and in the white-matter pathways connecting the brain with the arm. At the same time, the non-injured hand actually improved in certain motor skills, accompanied by changes in the opposite motor cortex.

Another study immobilized the dominant hand and wrist for just 72 hours. The researchers found increased cortical activation associated with sensory stimulation of the free hand and a shift toward more balanced activity between the two hemispheres. The non-immobilized hand also showed improved tactile discrimination.

And this isn't limited to people with actual injuries. Experiments using temporary arm immobilization in healthy adults have demonstrated that even hours of reduced limb use can alter motor-cortex excitability and the brain's capacity for plastic change.

But here's the important distinction

It would be misleading to say that breaking your arm simply “builds the cortex on the opposite side of your brain.”

The brain changes in both helpful and potentially unhelpful ways when a limb is immobilized. The cortex representing the immobilized limb can become less active, while increased use of the opposite limb can strengthen or expand its representation. Prolonged immobilization can also cause loss of strength, dexterity and normal motor control.

In other words, the brain adapts to what you do—or don't do.

And the takeaway—as in so many other things—is balance!

You don't need a broken arm to challenge your brain

Instead of breaking your dominant arm, try putting something else on your calendar:

“Use my non-dominant hand today.” Or for an hour, or half an hour, or fifteen minutes. It’s like vegetables. You get benefits even if you don’t eat a lot.

Brush your teeth with it. Eat with it. Open doors. Carry something light. Use your computer mouse differently. Practice simple movements that require coordination and attention.

You are deliberately asking your brain to solve familiar problems in an unfamiliar way.

You might even call it your “Pretend I Broke My Arm Day.”

The goal isn't to immobilize yourself or create an injury. It's to give your brain novel sensory and motor experiences.

Because neuroplasticity responds to use, repetition, attention and challenge.

Every time we learn a new movement, practice a new skill, change our habitual patterns or ask the less-used side of the body to participate, we give the nervous system new information to work with.

So instead of putting a cast on your arm, put a reminder on your calendar:

Challenge your brain.
Use the other hand.
Try something unfamiliar.
Pay attention to what your body is telling your brain.

Who knows? Maybe the all that new gray matter you’ll be developing will help you get more creative and strong in other areas of your life as well as that arm.

Wishing you good health, friends.

Research references:

• Langer N, Hänggi J, Müller NA, Simmen HP, Jäncke L. Effects of limb immobilization on brain plasticity. Neurology. 2012;78:182–188.

• Weibull A, Flondell M, Rosén B, Björkman A. Cerebral and clinical effects of short-term hand immobilisation. European Journal of Neuroscience. 2011.

• Opie GM, Evans A, Ridding MC, Semmler JG. Short-term immobilization influences use-dependent cortical plasticity and fine motor performance. Neuroscience. 2016.

• Barlow et al. Short-term arm immobilization modulates excitability of inhibitory circuits within, and between, primary motor cortices. Physiological Reports. 2022.

• Jäkel A, von Hauenschild P. A systematic review to evaluate the clinical benefits of craniosacral therapy. Complementary Therapies in Medicine. 2012.