You walk into a room and forget why. You reread the same email twice. You wake at 3:17 a.m. Again.

Is this stress? Hormones? Normal aging?

For many women, these signs creep into our awareness alongside the knowledge that while women live longer than men, we also account for nearly two-thirds of Alzheimer’s cases. Which means that, for women, longevity isn’t just about lifespan — it’s about brainspan.

And for women, what happens between roughly ages 35 and 60 plays an outsized role in shaping long-term cognitive health.

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😟 📈Chronic stress hits women’s cognition differently. Dive into a exploration of burnout and brain health here.

In part, it’s demographic. “Since the risk of cognitive decline increases with age, having a longer life expectancy is one reason women experience higher rates of dementia,” said Dr. Patricia Boyle, professor of psychiatry and behavioral sciences at Rush University and a trustee of the McKnight Brain Research Foundation. 

“Menopause-related hormone changes also contribute, as estrogen plays a key role in protecting memory and cognition,” Boyle says. Estrogen supports how the brain uses glucose for energy and helps regulate inflammation and synaptic function. During perimenopause and menopause, that signaling shifts rapidly. While women’s brains are highly adaptive, this long-term hormonal compensation may make them more vulnerable to metabolic and age-related strain later on according to Boyle.

But decline isn’t inevitable. Instead, it can be a signal that this is a critical window to prioritize brain health.

“What’s often misunderstood is that cognitive aging is a normal part of life,” says Boyle. In reality, people experience the changes associated with brain aging in different ways and at different rates. While popular culture tends to make it seem as though we are all destined to experience dementia or develop Alzheimer’s disease as we age, Boyle says that’s simply not true.

She adds that memory loss is often overemphasized as the first sign of cognitive decline. But women more commonly experience other symptoms such as changes in sleep, mood, attention, and executive function. 

“We want women in midlife who may be experiencing cognitive changes due to hormonal or other changes to understand that their brains are still highly adaptable during this stage, so any lifestyle changes they make during midlife may significantly reduce their risk of cognitive decline,” Boyle says.

Chronic stress for most women between roughly 35 and 65 years old is often underestimated, Boyle said, particularly for those caught in the “sandwich generation” balancing children, aging parents, work, and household responsibilities. Research has linked this kind of persistent stress in midlife to faster cognitive decline.

Sleep disruption is another early signal that often gets dismissed. “In perimenopause, insomnia, fragmented sleep, and earlier wake times reflect neurobiological changes in hormone and brain function long before cognitive impairment arises,” said Dr. Carleara Weiss, a clinician scientist specializing in behavioral sleep medicine and circadian rhythms. Consistently sleeping fewer than six hours per night in midlife has been linked to a higher dementia risk later in life.

Estrogen decline also affects muscle tone and metabolism, potentially increasing the likelihood of obstructive sleep apnea in midlife women, even without classic symptoms. Persistent sleep disturbances that impair daytime function warrant evaluation, Weiss said, including consideration of a sleep study.

When researchers say prevention starts decades earlier, it doesn’t mean supplement stacks or aggressive optimization. It means:

“The brain is always aging,” Boyle said. “How we take care of it in youth, adulthood, and midlife impacts cognitive function later in life.” It’s important to remember that women’s brains remain highly plastic in midlife, and lifestyle shifts during this window meaningfully reduce risk. The message from experts is remarkably consistent:

At the end of the day, brainspan is not about optimization or chasing perfection. It’s about protecting clarity, independence, and identity through regular, basic, healthy habits. 

The takeaway from the conversation is that midlife isn’t the beginning of decline. It’s the beginning of intentional protection.

Brain health isn’t a solo project. The Livelong Woman Ambassadors support deeper connections and conversations that center women’s longevity. If you care about prevention and elevating better conversations, we’d love to have you join us as a Livelong Ambassador for the Livelong Women’s Health Summit.

👉 Apply here

If you build science-backed solutions that support women’s long-term health, we’d love to connect. We’re currently welcoming vendors and partners for the Livelong ecosystem and upcoming events.

👉 Learn more about partnering with Livelong

The Livelong Women’s Circle is where topics like this go deeper — real conversations about sleep, stress, midlife changes, heart health, prevention, and what actually works as we age.

If you’re looking for a private, smart, and supportive space to ask questions and learn alongside other women who care about long-term health, you’re welcome here.

👉 Join the Livelong Women’s Circle

We asked, you answered!

Do you wake up during the night?

At least we are in good company? “I wake up and struggle to fall back asleep” was the most popular answer. Send any specific sleep-related issues to [email protected] for potential coverage in future issues. And I’m wishing you a good night’s rest in the near future.

Curious about your health? Liv will search everything we’ve published to help you find the answer. Chat with her here.