Alzheimer's Risk Reduction Can Start at Bedtime

Alzheimer’s disease can begin changing the brain long before memory problems become obvious, making early attention to everyday health especially important. During World Alzheimer’s Month, we look at sleep as a daily habit that can be tracked and strengthened over time. We explore how sleep may influence Alzheimer’s-related processes and what nighttime recovery may mean for APOE4 carriers, who face a higher risk of late-onset Alzheimer’s. To investigate this question, ZenoWell and the Phoenix Community followed 31 APOE4 carriers using a bedtime taVNS routine, observing encouraging changes in sleep scores, HRV, energy, wellbeing, and perceived sleep quality.

Why World Alzheimer’s Month Matters

Every September, World Alzheimer’s Month brings global attention to Alzheimer’s disease and the growing impact it has on individuals, families, caregivers, and healthcare systems. As populations age, more people are living with dementia, making earlier awareness and long-term brain health increasingly important. [1]

Alzheimer’s disease is different from occasionally forgetting a name, misplacing an object, or walking into a room and losing track of why. Its effects are progressive. Over time, a person may lose access to familiar memories, relationships, routines, and parts of the personal history that help shape who they are. [2]

That leads to a more urgent question: Before these changes become unmistakable, what can we do?

There is no single routine that can guarantee prevention. However, research suggests that some aspects of health may be worth addressing much earlier. One of the most familiar, measurable, and often overlooked is something we do every night: sleep.

Why We Looked at APOE4 Sleep and Bedtime

Sleep is one of the most practical places to begin looking earlier. It happens every night, changes can often be noticed before cognitive problems become obvious, and it supports many of the processes that help the brain maintain itself over time. [3-6]

During sleep, particularly deeper stages of non-REM sleep, the brain continues to organize memories, regulate neural activity, and remove metabolic waste. One system involved in this nighttime maintenance is the glymphatic system, a fluid-transport pathway that helps move waste products through and out of brain tissue. [3,6]

This process is especially relevant to Alzheimer’s research because it is connected with amyloid beta and tau. Abnormal accumulation of these proteins is a defining feature of Alzheimer’s disease. Research suggests that insufficient or fragmented sleep may interfere with the brain’s nighttime clearance processes and may be associated with changes in amyloid beta and tau. The relationship may also work in the other direction, as changes in brain regions involved in Alzheimer’s disease can make restful sleep more difficult. [4-6]

To explore this connection in everyday life, ZenoWell and phoenix community conducted a real-world observational study centered on bedtime. The study followed 31 people who carried APOE4 and examined changes in sleep, autonomic signals, and self-reported daily experiences while they used taVNS before bed.

APOE is a gene involved in lipid transport, neuronal repair, and brain maintenance. APOE4 is one of its genetic variants and is associated with a higher likelihood of developing late-onset Alzheimer’s disease. It is a risk factor rather than a diagnosis. Many APOE4 carriers never develop Alzheimer’s, and many people with Alzheimer’s do not carry this variant. [7]

APOE4 carriers were selected because they provide a relevant population for studying brain health before obvious cognitive symptoms appear. Sleep offered a repeatable observation window, while autonomic signals provided another way to examine how the body moved from daytime alertness into nighttime recovery.

Together, these elements shaped the central question behind the phoenix community study: could a consistent bedtime routine produce observable changes in sleep, autonomic regulation, and how participants felt during the day?

Why taVNS Became Part of the Question

To explore that question, the researchers needed an approach that could fit naturally into bedtime and interact with the systems involved in the transition to sleep. This led them to transcutaneous auricular vagus nerve stimulation, or taVNS.

Falling asleep is not simply a matter of closing the eyes. The body must gradually shift away from daytime alertness and toward a state that supports rest and recovery. This transition is partly regulated by the autonomic nervous system.

Its sympathetic branch helps the body remain alert and ready to respond. Its parasympathetic branch supports slower physiological activity, recovery, and rest. When this balance remains tilted toward arousal at night, it may be harder to fall asleep or return to sleep after waking.

The vagus nerve is an important part of this regulatory network. It connects the brainstem with organs including the heart, lungs, and digestive system, carrying information in both directions. Through these connections, it participates in the regulation of heart rate, breathing, digestion, stress responses, and recovery. [8]

taVNS delivers mild electrical stimulation through the outer ear, where a branch of the vagus nerve can be reached without surgery. Previous insomnia research has reported improvements in measures such as sleep quality and insomnia severity following repeated taVNS use. These findings made it reasonable to ask whether a short session before bed might support the body’s transition into rest. [9]

This is also why the phoenix community study examined HRV alongside sleep. HRV reflects variation in the time between heartbeats and is commonly used as a wearable indicator of autonomic regulation. It cannot diagnose Alzheimer’s disease, but it can provide information about how the nervous system is responding during rest and recovery.

For the phoenix community study, taVNS was therefore not selected as a treatment for Alzheimer’s disease. It was selected as a practical bedtime intervention that could be studied through sleep measures, autonomic signals, and participants’ daily experiences.

What We Observed in 31 APOE4 Carriers

The phoenix community study followed 31 APOE4 carriers who incorporated approximately 20 minutes of taVNS into their bedtime routine over a four-week period. Across the study, participants recorded 656 positive-use days and 644 sessions. [10]

The median participant recorded 23 use days. Of the 31 participants, 23 used taVNS on at least 10 days, 17 used it on at least 20 days, and 8 recorded at least 28 use days. [10]

The analysis compared each participant’s taVNS use nights with their own clearly identified non-use nights. This allowed the researchers to observe whether sleep, autonomic signals, and daily experiences changed alongside the bedtime routine.

Participants Reported Changes Beyond the Night Itself

Among the participants with paired self-reported data, the clearest changes appeared in energy, overall wellbeing, and perceived sleep quality:

• Energy increased by an average of 0.33 points.
• Wellbeing increased by an average of 0.28 points, with 8 of 10 participants showing improvement.
• Sleep quality increased by an average of 0.17 points, with 7 of 10 participants showing improvement.
• Mental sharpness showed a smaller average increase of 0.06 points.

The pattern suggests that the bedtime routine may have been connected not only with how participants experienced their sleep, but also with how they felt during the following day. This is particularly relevant to brain health because restorative sleep supports attention, memory processing, emotional regulation, and daytime functioning. [10]

Sleep Score and HRV Moved in a Positive Direction

Wearable data provided another view of the participants’ nighttime response.

Among six participants with eligible paired sleep-score data, the average sleep score was 2.1 points higher on taVNS use nights. Five of the six participants showed improvement.

Among nine participants with eligible HRV data, HRV measured as SDNN was an average of 3.9 milliseconds higher on use nights. Six of the nine participants showed improvement.

A higher sleep score may reflect changes across several aspects of sleep, rather than sleep duration alone. The increase in HRV is also notable because HRV provides a window into autonomic regulation and the body’s ability to move toward rest and recovery.

Together, the sleep-score and HRV findings point in a similar direction. On many of the nights when participants followed the taVNS bedtime routine, their wearable data reflected better overall sleep performance and a more favorable autonomic pattern. [10]

What Should Be Kept in Mind

This was a small, real-world observational study rather than a randomized clinical trial. Participants were living their normal lives, and many were also using supplements or following other health routines. The results should therefore be understood as early signals that can guide larger and more controlled studies.

Even with these limitations, the study connects several parts of the earlier brain-health question in a practical setting: a population with elevated genetic risk, a repeatable bedtime routine, measurable sleep outcomes, autonomic signals, and changes in how participants felt the next day.

What These Early Signals Mean for Alzheimer’s Research

The phoenix community study does not establish that taVNS can prevent or delay Alzheimer’s disease. It shows something more immediate: a bedtime routine designed around sleep and autonomic regulation was accompanied by measurable changes in sleep score, HRV, and how some APOE4 carriers felt during the day.

These findings matter because Alzheimer’s research increasingly looks beyond the point of diagnosis. If sleep disruption and changes in nighttime regulation can appear earlier, then sleep may offer a practical opportunity to observe brain-related health patterns over time. Wearable measurements such as sleep score and HRV make it possible to follow these patterns in daily life rather than relying only on occasional clinic visits.

A single night of data cannot tell us what is happening to long-term cognitive health. Repeated data, however, can help researchers identify individual patterns, compare responses, and develop better questions for controlled studies. In this sense, wearables are not diagnostic tools. They are a way to make sleep and autonomic changes more visible.

The next step is to study this bedtime approach in larger, randomized trials with standardized baseline periods, consistent stimulation settings, and longer follow-up. Future research can then examine whether changes in sleep and HRV are sustained and whether they are associated with cognitive outcomes or Alzheimer’s-related biomarkers.

For now, the phoenix community findings support a clear direction for continued research: bedtime routines, sleep quality, and wearable autonomic signals may help move the study of brain health into an earlier and more everyday setting.

World Alzheimer’s Month Is About Looking Earlier

This is where the phoenix community study connects back to the larger message of World Alzheimer’s Month. Alzheimer’s awareness should not begin only when memory loss disrupts daily life. It can begin earlier, with attention to the everyday factors that help support the brain over time.

Sleep is one of those factors, but it is not the only one. Cardiovascular and metabolic health affect the blood vessels and energy systems the brain depends on. Regular physical activity supports circulation, mobility, mood, and cognitive function. Social connection keeps the mind engaged and may help protect against the effects of isolation. Together, these habits form part of a broader approach to long-term brain health. [11]

Looking earlier also means noticing meaningful changes. Occasional forgetfulness is common, particularly during periods of stress or poor sleep. Persistent changes in memory, communication, judgment, or the ability to complete familiar tasks deserve professional evaluation. A wearable device or genetic result cannot provide a diagnosis. [2]

For ZenoWell, the phoenix community study represents an early step toward understanding how bedtime routines, sleep, and autonomic signals can be studied in everyday life. The goal is not to reduce Alzheimer’s prevention to a single device or nightly score. It is to explore how small, repeatable actions may help people pay closer attention to their health before unmistakable symptoms appear.

World Alzheimer’s Month brings Alzheimer’s disease into focus. Looking earlier expands that focus to the years before diagnosis, when supporting sleep, physical health, and social wellbeing can already become part of caring for the brain.

References

[1] Alzheimer’s Disease International. World Alzheimer’s Month Frequently Asked Questions. https://www.alzint.org/get-involved/world-alzheimers-month/frequently-asked-questions/

[2] National Institute on Aging. Alzheimer’s Disease Fact Sheet. National Institutes of Health. https://www.nia.nih.gov/health/alzheimers-and-dementia/alzheimers-disease-fact-sheet

[3] Xie L, Kang H, Xu Q, et al. Sleep drives metabolite clearance from the adult brain. Science. 2013;342(6156):373-377. doi:10.1126/science.1241224.

[4] Shokri-Kojori E, Wang GJ, Wiers CE, et al. Beta-amyloid accumulation in the human brain after one night of sleep deprivation. Proceedings of the National Academy of Sciences. 2018;115(17):4483-4488. doi:10.1073/pnas.1721694115.

[5] Lucey BP, Hicks TJ, McLeland JS, et al. Effect of sleep on overnight cerebrospinal fluid amyloid beta kinetics. Annals of Neurology. 2018;83(1):197-204. doi:10.1002/ana.25117.

[6] Dagum P, Elbert DL, Giovangrandi L, et al. The glymphatic system clears amyloid beta and tau from brain to plasma in humans. Nature Communications. 2026;17:715. doi:10.1038/s41467-026-68374-8.

[7] Fortea J, Pegueroles J, Alcolea D, et al. APOE4 homozygosity represents a distinct genetic form of Alzheimer’s disease. Nature Medicine. 2024;30:1284-1291. doi:10.1038/s41591-024-02931-w.

[8] Butt MF, Albusoda A, Farmer AD, Aziz Q. The anatomical basis for transcutaneous auricular vagus nerve stimulation. Journal of Anatomy. 2020;236(4):588-611. doi:10.1111/joa.13122.

[9] Zhang S, Zhao Y, Qin Z, et al. Transcutaneous auricular vagus nerve stimulation for chronic insomnia disorder: a randomized clinical trial. JAMA Network Open. 2024;7(12):e2451217. doi:10.1001/jamanetworkopen.2024.51217.

[10] phoenix community Research. Early Signals from 31 APOE4 Carriers Using ZenoWell taVNS. Public study report. July 2026.

[11] Livingston G, Huntley J, Liu KY, et al. Dementia prevention, intervention, and care: 2024 report of the Lancet standing Commission. The Lancet. 2024;404:572-628. doi:10.1016/S0140-6736(24)01296-0.

Medical note This article is for educational purposes only and does not constitute medical advice. taVNS is not presented as a method to prevent, diagnose, or treat Alzheimer’s disease. Individuals with persistent sleep or cognitive concerns should consult a qualified healthcare professional.