A doc debunks 3 brain myths your patients still believe—plus, a cheat sheet for you to share with patients

It’s a scene we’ve all encountered: Patients armed with a fun fact or two about the brain—“I only use 10% of it!”—or convinced that their daily crossword is a shield against cognitive decline.

A recent TikTok video from Amir Khan, ChB, MRCGP, DCH, DRCOG, a GP from the UK, debunks three of the most persistent brain myths among patients—the results of which might surprise you.

Myth 1: You only use 10% of your brain

This one has been around forever, and throughout our years in the clinic, we may have nodded along—perhaps even repeated it ourselves. But as Dr. Khan points out, modern neuroimaging shows virtually the entire brain is active at all times.

This common patient myth likely stems from early misinterpretations in 19th-century neuroscience when the function of many brain regions was still unknown.

Myth 2: Doing puzzles keeps your brain young

Crosswords, Sudoku, Wordle—they all feel like “brain training,” and they are, to a degree. They improve skills like pattern recognition and memory—but the benefits don’t necessarily extend to overall cognition or dementia prevention.

"Real brain youth comes from neuroplasticity, forming new connections," Dr. Khan said. "That means challenging your brain with new and complex tasks, learning a language, playing an instrument, dancing, even volunteering. Things that combine thinking, movement, and social interaction."

Myth 3: Listening to classical music makes you smarter

The “Mozart effect” has enjoyed a long cultural life, thanks to a 1993 study^[] showing a small, short-lived boost in spatial reasoning. Later research clarified it wasn’t the music itself but the mood and arousal it produced.

What actually keeps the brain healthy

Dr. Khan provides practical, evidence-based guidance that you can use as a cheat sheet when talking with patients about habits that actually keep the brain sharp:

• Exercise: This "increases blood flow to the brain and increases brain derived neurotrophic factor, which helps new neurons grow," Dr. Khan said.

• Sleep: "During deep sleep, your brain clears out waste proteins like beta amyloid, which have been linked to Alzheimer's," he said.

• Nutrition: "The Mediterranean diet is rich in omega-3s," Dr. Khan said. "Olive oil, whole grains, and colorful vegetables are strongly linked to lower dementia risk."

• Social engagement and lifelong learning: "Isolation increases cognitive decline risk," Dr. Khan said. "Meaningful connection and curiosity protect your brain long-term."