For 2,000 years, doctors told us muscle would kill our brains. Turns out, it's the exact opposite.

TODAY'S BRIEF: • Why ancient medicine feared muscle • The 90-year-olds who gained 174% strength • Your weekly win: It's never too late (or early) to start

The 2,000-Year Mistake About Your Muscles

Ancient Roman doctors believed that building muscle would literally smother your soul. They thought if you got too muscular, it would make it impossible to think clearly.

Let that sink in. The people in charge of health care actively discouraged strength training because they thought it would make you stupid.

Fast forward to today, and the research shows they had it completely backward. A University of Sydney study found that heavy weight training actually increases the size of your brain's posterior cingulate cortex—the part responsible for empathy and emotional memory. It's also the first part of the brain to shrink in Alzheimer's patients, often before any symptoms show up.

So not only does strength training not hurt your brain, it actively protects it.

Here's the wild part: scientists didn't even understand that muscles were responsible for movement until the 17th century. For thousands of years, doctors thought muscles were just padding or insulation. Later, Romans believed muscles were factories that produced tendons, and those tendons moved us via trapped hot air in our bodies. (Yes, really.)

It wasn't until the same year Copernicus published his theory that Earth revolves around the sun that anyone figured out that the fleshy part of muscle is what actually moves us.

Why does this history lesson matter? Because medical schools still aren't teaching this stuff properly. A survey of medical school deans found that 96% believed graduating students should be able to prescribe exercise, but only 6% of schools actually required instruction on it.

Translation: most doctors want to help you with exercise, but they literally weren't taught how.

The science is clear now. Strong muscles create strong bones, better cardiovascular health, improved mental health, reduced dementia risk, and longer independent living. But we're still playing catch-up from 2,000 years of getting it wrong.

The good news? You don't need to wait for the medical system to catch up. You can start today.

The Nursing Home Study That Changes Everything

Maria Fiatarone did a study on 90-year-olds in a nursing home. These weren't gym people. They grew up during the Depression. Many were Holocaust survivors who had never prioritized exercise.

They did one exercise: knee extensions. Three sets of 10, three times a week, for eight weeks.

The results:

One man went from using a walker to using a cane. Another threw his cane away entirely. When they scaled up the study to 100 people, just getting stronger made participants 35% more active without any additional prompting.

The takeaway? You don't need fancy functional training that mimics daily life. If you give people—especially older people—the raw strength to move, they'll naturally do more.

And here's the kicker: sarcopenia (age-related muscle loss) doesn't start when you're old. It starts in early life. Which means if you're in your 20s, 30s, or 40s and not strength training, you're already heading down the wrong path.

It's never too late to start. But it's also never too early.

Stop waiting for the "right time" to start lifting.

Whether you're 25 or 75, your muscles respond to training. The 90-year-olds proved that. But the earlier you start, the more you're banking strength for your future.

If you're intimidated by the gym, remember: a study of 2,500 people aged 60-72 in strength training programs found exactly one injury—a case of shoulder pain.

Find one person who knows how to lift. Ask for help. Start with one exercise. Most gyms will help you for free if you ask.

Your future self will thank you.

We want to create content that actually helps you. Take 5 seconds to tell us what you're struggling with most right now, and we'll prioritize that topic in upcoming newsletters. Which health topic do you want us to cover next?

That's your brief. Stay strong.

- The Male Brief

P.S. Doctors used to prescribe masturbation for prostatitis by literally writing it on a prescription pad and signing it. Maybe it's time they started prescribing strength training the same way.