A new study suggests that insomnia may be linked to a staggering 12 percent of dementia cases. If you’re used to measuring risk, this is a wake-up call to address your sleep hygiene as a hedge against cognitive decline. Marla Broadfoot dives into the data for Science News.

🗞️ News to lose sleep over

Researchers at Massachusetts General Hospital in Boston analyzed longitudinal data from nearly 6,000 participants in the National Health & Aging Trends Study to determine how sleep disturbances impact long-term cognitive health. The researchers focused on two primary indicators of insomnia, falling asleep and staying asleep — and used statistical modeling to calculate the percentage of dementia cases that could theoretically be prevented if these sleep issues were eliminated. They found that individuals who had trouble falling or staying asleep had a significantly higher risk of cognitive decline. The relationship is complicated: other research suggests sleep problems might be an effect of dementia rather than a cause. Taken together, the findings suggest that, while no cause-and-effect relationship between insomnia and dementia has been established, sleep problems are a modifiable risk factor and should therefore be examined more closely.

🌊 The silver tsunami and the cost of forgetfulness

The economic impact of an aging population with cognitive decline is one of the most significant events in global finance. In the U.S. alone, the cost of caring for people with Alzheimer’s and other neurodegenerative disorders is in the hundreds of billions and rising as the “silver tsunami” reaches the shore. Health care providers could look to powerful low-cost strategies to reduce the global burden of dementia, such as educating and counseling patients on sleep hygiene, and diagnosing and treating interfering conditions such as sleep apnea. Innovations in sleep tech could also help.

🌚 Investing in the night shift

As the medical community prioritizes sleep, these companies are scaling the tools to manage our ZZZs:

• Eisai (OTC: ESAIY): In the pharma sector, the focus has shifted from triggering sleepiness to “suppressing hyperactive wakefulness.” Eisai’s Dayvigo (lemborexant), which blocks orexin receptors in the brain to turn off wakefulness, is the first drug of its kind to be approved for the massive Chinese market. Unlike older sedatives like Ambien, this class of drug aims to preserve natural sleep cycles. Eisai’s annual revenue exceeds $5 billion.
  
• Oura: Known for its smart ring, Oura’s consumer-facing sleep telemetry data is used in studies to track the long-term correlation between sleep quality and cognitive health. Oura has raised over $1.5 billion to date, including a $900 million Series E round in late 2025, backed by firms like Lifeline Ventures and Forerunner Ventures.
  
• Eight Sleep: This “sleep system” incorporates smart mattresses that use thermal regulation and personalized profiles. As published in a peer-reviewed study, the system was found to optimize deep, light, and REM sleep stages. Eight Sleep has secured over $260 million in funding, including a recent $100 million Series D round.
  
• Olo: New to the market, this startup says its spatial audio helps people calm down, reduce anxiety and fall asleep. Backed by peer-reviewed research, the company’s therapeutic app — combining an eye mask and audio platform — creates an environment that helps users drop their stress levels. Olo is currently in a high-growth phase, with backers including serial entrepreneur Mark Pincus and undisclosed advocates from OpenAI and Apple.

In a world that’s always on, the smartest investment may be in the tech that helps us shut it all down.

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