When I was in high school, I always liked to look in the back of the textbook to get the answers first.

That way, I would know if I was on the right track in solving a problem. So, I will try to give the answers first.

To keep your brain (and yourself as a whole) healthy, know the answers to the questions:

What is the health of my heart and circulation?

What can I do, or what can I do differently to keep my circulation working as safely and efficiently as possible?

Fundamentally, these are the only questions I ever get asked. The questions are simple, but the answers are different for all of us.

What Is a Stroke, Exactly?

A few definitions are in order. First of all, what is a stroke? Technically speaking, we call a stroke a cerebrovascular accident. (As you can see, doctors love to confuse things by using Latin and Greek. I supposed lawyers are just as bad.) Cerebro means “brain.” Vascular means “blood vessel,” or refers to circulation.

And accident, well, that always means something bad.

A stroke is damage to the brain caused by a problem with blood flow to the brain.

This is why cardiovascular doctors (also known as cardiologists) have always been responsible for preventing strokes, although they are not the doctors called when you have a stroke. The doctors called when you have a stroke are neurologists (brain specialists). They should not be the first doctor you see to prevent a stroke. Hopefully, you will never need to see one. You should see your primary care doctor or a cardiologist first.

A stroke is not a heart attack. Sometime in the past 50 years, our medical vocabulary became even more confusing than it already was. The terms stroke and heart attack became interchangeable. They have a lot in common, but they are different things. A stroke is brain damage. A heart attack is heart damage.

Cardiologists prevent both. Historically we just have not been very aggressive about preventing strokes. Having a stroke means you have had brain damage, which means a neurologist (a brain specialist) will need to help you. Preventing a stroke means keeping your circulation healthy, which is not a job for a brain specialist. It’s a job for a circulation specialist (that is, a cardiologist).

Biologically speaking, there are several types of strokes, but most of them are caused by a clot jamming up the blood flow to the brain. Those clots tend to come from the heart or the big blood vessels leading to the brain (the carotid arteries), or they can form in the smaller blood vessels within the brain. No matter what, you don’t want blood clots in your brain. That’s a stroke.

There are also “bleeding strokes,” but they are not the common ones. In fact, many bleeds in the brain start as a clot. We tend to fear bleeding, but in fact, clots are a much, much bigger problem.

Clots can be prevented. That’s part of how we prevent strokes.

What Are the Signs of a Stroke?

A common question is what are the signs of a stroke? Well, the whole goal is to not have a stroke in the first place, but it is worth knowing what happens when you do clot off part of your brain. Remember, a stroke is brain damage. So, whatever part of the brain you damage may not work quite right again. It may not work at all.

Pick a function that your brain controls. If you clot off the part of the brain that controls that function, it won’t work. Just about anything related to brain function can be lost by a stroke.

For example, you may lose the ability to speak, to understand words, to see, to swallow, to move your arm or leg. You may not think right. You may be confused. Your face may droop. You may collapse. For better or worse, most strokes don’t kill you. They just take something away, usually forever.

If you have a stroke, you will get to know a neurologist all too well. They are the experts who can tell you just how much of your brain has been damaged and how likely you are to recover what you have lost.

There are many books to help you understand how to recover from brain damage. The book I wrote with Kristin E. Thomas, MD, You Can Prevent a Stroke, is not one of them. I find them all a little depressing.

If you do have a stroke, sometimes dramatic things can be done to try to rescue your brain. Several new studies have been published about some of these high-tech procedures (where tubes get stuck into your head to suck out clots, or clots are melted with drugs). One of my favorite patients recently asked me about these treatments. He wanted to know what was the best way to treat a stroke. The answer was really quite simple.

The best way to treat a stroke is to not have one in the first place.

What is a TIA? TIA stands for transient ischemic attack. They are often referred to as “ministrokes.” Transient implies that you have symptoms that come and go. They are not permanent. Ischemic means some part of your body did not get enough blood. In this case, we are talking about part of the brain not getting blood. Attack, well, that’s got to be bad.

A TIA is a transient ischemic attack, or ministroke, where symptoms spontaneously recover without permanent damage.

Having a TIA means that some part of your brain did not get enough blood, and it didn’t work. Like with a stroke, any part of the brain may be at risk. The difference between a TIA and a stroke is that a stroke leaves evidence of permanent damage.

Usually, that evidence of a TIA is seen with an MRI scan of your brain. If you have symptoms of some part of your brain not working, and the symptoms get better, and a brain scan shows no evidence of permanent damage (that is, a stroke), then consider yourself lucky. You have had a TIA. You have dodged a bullet. You need to think very hard about how you, and your doctor, are going to prevent your stroke, because it is coming.

You do not need to wait for symptoms before you actively prevent a stroke.

A scenario we see every day involves seemingly cryptic or mysterious terminology on a brain scan (MRI) report. Someone undergoes a brain MRI and there is evidence of an old stroke, or many old strokes. The MRI is read as “small vessel ischemic disease” or “age-related atrophy.” All of this means that at some point, the brain did not get enough blood flow, blood flow was interrupted, or brain circulation clotted. It is entirely possible, and actually quite common, to find brain damage on MRI that you were never symptomatically aware of.

In the past, we often felt that these abnormal scans, in which the damage shown never presented symptomatically, were much like the proverbial tree falling in a forest. If no one is there to hear the tree fall, does it make a noise? If you never have any symptoms, does it matter that the MRI says you had a stroke?

What is Vascular Dementia?

If enough trees fall in the forest, there’s no more forest. If enough of your brain gets damaged, you will eventually become demented.

Vascular dementia is the loss of brain function, especially the ability to think, due to inadequate or interrupted blood flow.

There are actually several ways in which we can become demented. We tend to use terms like Alzheimer’s and dementia interchangeably, but technically they are different. Dementia means that your brain doesn’t work. Alzheimer’s is a specific disease in which unusual proteins build up in the brain for unknown reasons.

We have no good way of preventing or treating Alzheimer’s. But some of what we think of as Alzheimer’s is actually vascular dementia. And Mother Nature says you can have both. We may not be able to prevent Alzheimer’s, but there is a lot that we can do to prevent vascular dementia.

We used to say that old folks simply became “senile.” The inference was that their memory was gone. Their ability to think rationally was gone. They were maybe a little goofy if not downright crazy. It finally evolved into an insult. If anyone was ever confused or forgetful, they were accused of being senile.

Well, technically, senile just means “old.”

Natural aging predictably changes circulation. As circulation changes, blood flow to the brain can become less reliable. Clots form. Blood flow can be interrupted. The heart may not pump enough blood to the brain, and the brain suffers. Then you can in fact become “senile” if you develop vascular dementia.

Age is going to change circulation. It should come as no surprise that the brain suffers when circulation is inadequate.

Senility is vascular dementia. If you want to avoid it, keep the circulation to your brain healthy.

Perhaps the most important point is this: We do not need to simply accept growing old the way our grandparents did. We have the ability to keep the effects of time in check (at least when it comes to the heart and circulation). But we need to make the choice to be an active participant. We can prevent the changes to the heart and circulation that lead to strokes, brain damage, and vascular dementia. They do not prevent themselves.

5 Keys to Preventing Strokes and Vascular Dementia

The basics of prevention are already mentioned above: Know your heart and vascular health, and ask if you are doing everything you can to keep things working. Well, how does one do that?

1. Establish a relationship with a physician.

2. Know the health of your heart.

3. Know the health of your arteries.

4. Know the regularity of your heartbeat.

5. Know if it’s time to take a medicine to prevent plaque in your arteries and whether you need a pill to prevent a blood clot.

This is what we now call the Foxhall Formula, or protocol. It is a short list of steps everyone can take to make sure they are preventing strokes.

To prevent strokes, it may not take a whole village, but it does take a good relationship with a doctor. There are things you will need to do, and things you will need your doctor to do with you.

Notice the list does not mention diet or exercise. Of course, fitness helps everything. A rational diet is important (more on that later), but if a magic fruit existed to keep our arteries perfectly clean and plaque free, I’d like to think we would have found it by now.

The list does include a lot of questions to be answered; fortunately they are all easy to answer — but you have to ask.

This excerpt is adapted from You Can Prevent a Stroke, by Joshua S. Yamamoto and Kristin E. Thomas and is printed with permission from RosettaBooks.

Joshua S. Yamamoto, MD, trained on the Osler Medical Service at The Johns Hopkins Hospital, and then completed cardiology training at the National Naval Medical Center and Georgetown University. In 2005, he was lent to the Army and served in Kuwait as the theater cardiologist for the ongoing wars in Iraq and Afghanistan.

Kristin E. Thomas, MD, became the first “hospitalist” physician of Johns Hopkins before accepting the position of Assistant Chief of Service (Chief Resident). She and her husband formed a practice, Foxhall Medicine, PLLC. In 2015 she started the Foxhall Foundation, which initially worked to help provide services for patients with dementia, a not-for-profit, educational organization dedicated to helping everyone age well. All proceeds from the sales of You Can Prevent a Stroke go to support the foundation.