People want a perfect memory. They wish that they can remember everything that they want to remember. But it doesn’t work like that.

Most people over the age of 50 think that forgetting someone’s name or forgetting why they went into the kitchen is a sign of Alzheimer’s. It isn’t. Most of our forgetfulness is perfectly normal.

If you are worried about developing Alzheimer’s or another form of dementia, some simple lifestyle modifications can help prevent it: getting enough sleep, exercising, eating a balanced diet, and managing stress.

LISA GENOVA: People think that memory is supposed to be perfect. They think it's designed to remember everything they want to remember. And this just isn't how it works. Our brains are not designed to remember people's names, to do something later, or to catalog everything we encounter. But what I found over and over is that everybody over the age of 50, 60, 70, they think that all kinds of forgetting mean they have Alzheimer's. They'd say things to me like, "Well, I'm always forgetting names. And if I don't write down what I have to do later, I won't remember to do it. And I'm always walking into the kitchen and I don't know why I'm in there." So these people are panicked and afraid and stressed out and really ashamed of these moments of forgetting, which are actually totally normal. 

My name is Lisa Genova. I am an author and neuroscientist. The name of my book is 'Remember: The Science of Memory and The Art of Forgetting.' 

I've been talking about Alzheimer's using 'Still Alice' as a vehicle for that conversation for over a decade- trying to help folks understand what it feels like to have Alzheimer's, and to recognize what those symptoms of dementia are. Alzheimer's begins with a protein called 'amyloid beta.' It's a sticky protein, it'll bind to itself and form 'amyloid plaques.' And if enough amyloid plaques accumulate in your brain, at some point it reaches a tipping point that causes neurofibrillary tangles, neuroinflammation, cell death, and all of the symptoms that we classically know of as Alzheimer's. Prior to that tipping point, you're symptom-free. It's sort of like if you have high cholesterol it doesn't mean you're gonna have a heart attack. 

So below the tipping point, your symptoms of forgetting are all normal. "Why did I come in this room?" "Where did I park my car?" "Oh, what's his name?" "I need to remember to buy something later; I forgot." That's totally normal. After the tipping point, the glitches in memory formation and retrieval are different. Alzheimer's begins in your hippocampus, the very place in your brain that's responsible for forming new memories. So, the very first symptoms of Alzheimer's will be not remembering what someone said a few minutes ago, repeating yourself over and over, because you don't remember what you just said, not remembering what happened last week even if it was really emotional, meaningful, new, surprising or repeated. Things that you would normally remember from last week, won't get consolidated, because your hippocampus is under attack. Alzheimer's will move, it doesn't just stay in your hippocampus. It invades your frontal lobe, so you'll have problems with problem solving, decision making. It invades parts of your brain that have to do with where things are in space, so you might get lost in the neighborhood you've lived in your whole life. It will invade the parts of your brain that have to do with language, so you'll start having trouble coming up with words more and more. The disease will move on to your limbic system and cause changes in emotion and personality. So what's the good news here? There's actually a lot of it. 

The vast majority of what we forget every single day is totally normal, and probably will be throughout your lifetime. For the vast majority of us, Alzheimer's is not our brain's destiny. Only 2% of folks have Alzheimer's that is 100% inherited. This accumulation of amyloid plaques takes 15 to 20 years, and can be influenced by how we live. So what are the things that influence those amyloid plaque levels? 

Sleep. While you sleep, there are cells in your brain called 'glial cells.' These are the janitors of your brain. It's the sewage and sanitation department. They get really busy clearing away all of the metabolic debris that accumulated in your brain while you were in the business of being awake. And one of the things it critically clears away is amyloid beta. So if you don't get enough sleep, the glial cells won't have enough time to do their jobs and you'll wake up at the morning with some extra amyloid in your brain that wasn't cleared away. If this happens over decades, right, 15 to 20 years of amyloid plaque accumulation, you are increasing your risk of developing Alzheimer's. 

Diet. There have been many really good studies that have shown that being on a 'Mediterranean' or 'MIND' diet can reduce your risk of Alzheimer's from anywhere from a third to a half. This means eating the rainbow: The green leafy vegetables, the brightly colored fruits and berries, fatty fishes, nuts, beans, olive oils. That's the food that's gonna support your brain health and help you prevent Alzheimer's. 

Exercise. It works to reduce your risk of Alzheimer's. A brisk walk for 30 minutes, four to five times a week is enough to decrease your amyloid plaque levels and reduce your risk of developing Alzheimer's by a third to a half. Again, this is significant. If I offered you a pill that would reduce your risk of Alzheimer's by 50%, you'd take it. So we wanna get up and move around. 

Chronic stress is really bad for our memory, both today in creating new memories and it will increase your risk of developing Alzheimer's in the future. With chronic stress, your cortisol levels remain elevated. You're in a constant state of fight or flight. This is really bad for your hippocampus. It will actually shrink the size of your hippocampus by inhibiting 'neurogenesis'- it will inhibit the birth of new neurons there. So now you've got a smaller structure that's essential for the formation of new memories and is the very first place hit by Alzheimer's. This is why we wanna do things that manage stress. Yoga, meditation, mindfulness, exercise, and being with people. 

All of these have been shown to restore your cortisol levels and it will restore the size of your hippocampus. Learning new things. Let's say you haven't done any of those things I just mentioned. Let's say you're chronically sleep-deprived, you're watching Netflix til 3:00 AM, you've been raising kids for decades, you're a woman, you've gone through menopause. I don't need to list all that. Let's say your amyloid plaque levels have reached that tipping point, and it's triggered the cascade that causes Alzheimer's. 

If you've lived a life where you're cognitively active, you're regularly learning new things- you are building what we call a 'cognitive reserve.' Every time you learn something new, you're building new synapses, you're building new neural connections. So what does this have to do with Alzheimer's? If I have some Alzheimer's disease pathology present in my brain, amyloid plaques are gunking up the connections between a certain number of neurons, blocking some synapses. But what if I've built a lot of redundant connections? I've got an abundance and a redundancy in connections. I can dance around those roadblocks. I can take detours and still get to the memory I'm trying to get to. So learning new things gives us a way to build an Alzheimer's-resistant brain. The good news is a lot of these lifestyle factors work as well as any pill that we might develop for preventing Alzheimer's. We just have to do them. Forgetting due to Alzheimer's is scary. But normal forgetting, the stuff we forget every day, shouldn't be.