There’s an old joke that men have two brains, and which one we’re thinking with depends on the situation.

I’ve spent much of my career taking care of one of them.

But lately I’ve been thinking more about the other.

My friend Dr. Ashanthi Gajaweera is a neurologist who has spent more than 20 years caring for patients with dementia.

She now runs Healthspan Neurology and has built a program specifically around reducing dementia risk before people develop symptoms.

What caught my attention is how familiar much of it sounds.

Blood pressure. Cholesterol. Diabetes and metabolic health.

Exercise. Sleep apnea. Body composition.

Hormones. Smoking. Alcohol. Nutrition.

These are many of the same conversations we have about heart health, erections, testosterone and aging well.

Apparently the two brains have been comparing notes.

We tend to think of dementia as something that happens much later.

Someone starts forgetting names or getting lost, the family notices, and eventually a neurologist gets involved.

But the processes that contribute to cognitive decline can begin decades earlier. Vascular damage accumulates.

Metabolic disease matters. Sleep matters. Genetics matter.

And while none of us can guarantee that we won’t develop dementia, some of the risk appears to be modifiable.

That’s an important distinction.

Dr. Gajaweera told me that for years families of her dementia patients would ask, “What can I do so this doesn’t happen to me?”

Like many physicians, she would tell them to eat well, exercise and sleep.

All good advice.

But “eat better and exercise” isn’t much of a plan.

Her approach now is more interesting: what do you want your brain and body to be capable of at 80 or 90?

Then look at your individual risks and work backward.

I like that question.

Maybe you want to manage your own finances. Travel. Keep working.

Read complicated books. Have great conversations. Remember your grandchildren’s stories.

Live independently.

And yes, maybe you still want to have sex. Sexual health isn’t separate from this conversation.

The vascular and metabolic problems that damage erections in middle age don’t suddenly become irrelevant when we start talking about the brain.

Sleep apnea doesn’t care whether I’m worried about your testosterone, your blood pressure or your cognition.

It’s all the same man.

I’m not suggesting we can exercise, sleep or statin our way out of every case of dementia.

We can’t.

Genetics, aging and biology still get a vote.

But “I can’t control the outcome” and “there’s nothing I can do” are very different ideas.

We’ve spent plenty of time in this newsletter trying to preserve what men want their bodies to be capable of later in life.

Maybe we should be putting some reps into the other brain too.